Левофлорипин Uses, Dosage, Side Effects and more

Isoniazid inhibits the synthesis of mycoloic acids in susceptible bacteria which results in loss of acid-fastness and disruption of bacterial cell wall. At therapeutic levels, it is bacteriocidal against actively growing intracellular and extracellular Mycobacterium tuberculosis organisms.

Isoniazid is a bactericidal agent active against organisms of the genus Mycobacterium, specifically M. tuberculosis, M. bovis and M. kansasii. It is a highly specific agent, ineffective against other microorganisms. Isoniazid is bactericidal when mycobacteria grow rapidly and bacteriostatic when they grow slowly.

Levofloxacin exerts antibacterial action by inhibiting bacterial topoisomerase IV and DNA gyrase, the enzymes required for DNA replication, transcription repair and recombination. It has in vitro activity against a wide range of gm-ve and gm+ve microorganisms.

Levofloxacin is bactericidal and exerts its antimicrobial effects via inhibition of bacterial DNA replication. It has a relatively long duration of action in comparison with other antibiotics that allows for once or twice daily dosing. Levofloxacin is associated with QTc-interval prolongation and should be used with caution in patients with other risk factors for prolongation (e.g. hypokalemia, concomitant medications).

Levofloxacin has demonstrated in vitro activity against a number of aerobic gram-positive and gram-negative bacteria and may carry some activity against certain species of anaerobic bacteria and other pathogens such as Chlamydia and Legionella. Resistance to levofloxacin may develop, and is generally due to mutations in DNA gyrase or topoisomerase IV, or via alterations to drug efflux. Cross-resistance may occur between levofloxacin and other fluoroquinolones, but is unlikely to develop between levofloxacin and other antibiotic classes (e.g. macrolides) due to significant differences in chemical structure and mechanism of action.

As antimicrobial susceptibility patterns are geographically distinct, local antibiograms should be consulted to ensure adequate coverage of relevant pathogens prior to use.

Pyrazinamide may be bacteriostatic or bactericidal in action, depending on the concentration of the drug attained at the site of the infection and the susceptibility of the infecting organism. Its activity appears to partly depend on conversion of the drug to pyrazinoic acid (POA), which lowers the pH of the environment below that which is necessary for growth of Mycobacterium tuberculosis. Susceptible strains of M. tuberculosis produce pyrazinamidase, an enzyme that deaminates pyrazinamide to POA, and the in vitro susceptibility of a given strain of the organism appears to correspond to its pyrazinamidase activity.

Pyrazinamide kills or stops the growth of certain bacteria that cause tuberculosis (TB). It is used with other drugs to treat tuberculosis. It is a highly specific agent and is active only against Mycobacterium tuberculosis. In vitro and in vivo, the drug is active only at a slightly acid pH. Pyrazinamie gets activated to Pyrazinoic acid in the bacilli where it interferes with fatty acid synthase FAS I. This interferes with the bacteriums ability to synthesize new fatty acids, required for growth and replication.

Rifampicin suppresses initiation of chain formation for RNA synthesis in susceptible bacteria by binding to the β subunit of DNA-dependent RNA polymerase, thus blocking RNA transcription.

Rifampin is an antibiotic that inhibits DNA-dependent RNA polymerase activity in susceptible cells. Specifically, it interacts with bacterial RNA polymerase but does not inhibit the mammalian enzyme. It is bactericidal and has a very broad spectrum of activity against most gram-positive and gram-negative organisms (including Pseudomonas aeruginosa) and specifically Mycobacterium tuberculosis. Because of rapid emergence of resistant bacteria, use is restricted to treatment of mycobacterial infections and a few other indications. Rifampin is well absorbed when taken orally and is distributed widely in body tissues and fluids, including the CSF. It is metabolized in the liver and eliminated in bile and, to a much lesser extent, in urine, but dose adjustments are unnecessary with renal insufficiency.

Attribute	Details
Trade Name	Левофлорипин
Generic	Isoniazid + Levofloxacin + Pyrazinamide + Rifampicin + [pyridoxine]
Type
Therapeutic Class
Manufacturer
Available Country	Russia
Last Updated:	January 7, 2025 at 1:49 am

Uses

Isoniazid is used for the treatment of all forms of tuberculosis in which organisms are susceptible.

Levofloxacin Tablet is used for Acute maxillary sinusitis , Acute bacterial exacerbation of chronic bronchitis , Nosocomial pneumonia Community acquired pneumonia, Uncomplicated urinary tract infections Complicated urinary tract infections, Acute pyelonephritis, Uncomplicated & complicated skin and skin structure infections, Chronic bacterial prostatitis

Levofloxacin Injection is used to treat Acute maxillary sinusitis, acute bacterial exacerbation of chronic bronchitis, nosocomial pneumonia, community acquired pneumonia, uncomplicated urinary tract infections, complicated urinary tract infections, acute pyelonephritis, uncomplicated & complicated skin and skin structure infections including abscesses, cellulitis, furuncles, impetigo, pyoderma, wound infections, chronic bacterial prostatitis and typhoid fever.

Levofloxacin Injection has

• Proven clinical success in hospital infections
• Reaches high concentrations in lung, urine, skin and prostate
• Ensures excellent gram-positive and gram-negative bacterial coverage, Offers better option for switch therapy

Levofloxacin Eye drops is used for the treatment of corneal ulcer caused by susceptible strains of the following bacteria:

• Gram-positive Bacteria: Corynebacterium species, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, Viridans group streptococci
• Gram-negative Bacteria: Pseudomonas aeruginosa, Serratia marcescens.

Pyrazinamide is used for the initial treatment of active tuberculosis in adults and children when combined with other antituberculous agents.

• The current recommendation of the CDC for drug-susceptible disease is to use a six-month regimen for initial treatment of active tuberculosis, consisting of isoniazid, rifampin and Pyrazinamide given for 2 months, followed by isoniazid and rifampin for 4 months
• Patients with drug-resistant disease should be treated with regimens individualized to their situation. Pyrazinamide frequently will be an important component of such therapy.
• In patients with concomitant HIV infection, the physician should be aware of current recommendation of CDC. It is possible these patients may require a longer course of treatment

It is also used after treatment failure with other primary drugs in any form of active tuberculosis.

Pyrazinamide should only be used in conjunction with other effective antituberculous agents.

In the treatment of both tuberculosis and the meningococcal carrier state, the small number of resistant cells present within large populations of susceptible cells can rapidly become the predominant type. Bacteriologic cultures should be obtained before the start of therapy to confirm the susceptibility of the organism to rifampinand they should be repeated throughout therapy to monitor the response to treatment. Since resistance can emerge rapidly, susceptibility tests should be performed in the event of persistent positive cultures during the course of treatment. If test results show resistance to rifampin and the patient is not responding to therapy, the drug regimen should be modified.

Левофлорипин is also used to associated treatment for these conditions: Active Tuberculosis, Mycobacterium kansasii infection, Late phase TuberculosisAbscesses caused by susceptible bacteria, Acute Bacterial Exacerbation of Chronic Bronchitis (ABECB) caused by susceptible bacteria, Acute Pyelonephritis caused by Infection Due to Escherichia Coli, Bacterial Conjunctivitis caused by susceptible bacteria, Cellulitis caused by susceptible bacteria, Community Acquired Pneumonia (CAP) caused by susceptible bacteria, Furuncle caused by susceptible bacteria, Impetigo caused by susceptible bacteria, Nosocomial Pneumonia caused by Pseudomonas Infections, Nosocomial Pneumonia caused by susceptible bacteria, Plague caused by Yersinia pestis, Pyoderma caused by susceptible bacteria, Wound Infections caused by susceptible bacteria, Acute bacterial sinusitis caused by susceptible bacteria, Chronic Bacterial prostatitis caused by susceptible bacteria, Chronic Pseudomonas Infections, Complicated Urinary Tract Infection caused by susceptible bacteria, Complicated skin and skin-structure infections caused by susceptible bacteria, Inhaled anthrax caused by Bacillus anthracis, Uncomplicated Urinary Tract Infection caused by susceptible bacteria, Uncomplicated skin and skin-structure infections caused by susceptible bacteriaActive Tuberculosis, Pulmonary Tuberculosis (TB)Cholestatic pruritus, MRSA Infection, Prosthetic Joint Infection, Asymptomatic Neisseria meningitidis carrier of the nasopharynx, Initial phase Tuberculosis, Late phase Tuberculosis, Antibacterial therapy

How Левофлорипин works

Isoniazid is a prodrug and must be activated by bacterial catalase. Specficially, activation is associated with reduction of the mycobacterial ferric KatG catalase-peroxidase by hydrazine and reaction with oxygen to form an oxyferrous enzyme complex. Once activated, isoniazid inhibits the synthesis of mycoloic acids, an essential component of the bacterial cell wall. At therapeutic levels isoniazid is bacteriocidal against actively growing intracellular and extracellular Mycobacterium tuberculosis organisms. Specifically isoniazid inhibits InhA, the enoyl reductase from Mycobacterium tuberculosis, by forming a covalent adduct with the NAD cofactor. It is the INH-NAD adduct that acts as a slow, tight-binding competitive inhibitor of InhA.

Levofloxacin, like other fluoroquinolone antibiotics, exerts its antimicrobial activity via the inhibition of two key bacterial enzymes: DNA gyrase and topoisomerase IV. Both targets are type II topoisomerases, but have unique functions within the bacterial cell. DNA gyrase is an enzyme found only in bacteria that introduces negative supercoils into DNA during replication - this helps to relieve torsional strain caused by the introduction of positive supercoils during replication, and these negative supercoils are essential for chromosome condensation and the promotion of transcription initiation. It is comprised of four subunits (two A subunits and two B subunits) of which the A subunits appear to be the target of fluoroquinolone antibiotics. Bacterial topoisomerase IV, in addition to contributing to the relaxation of positive supercoils, is essential at the terminal stages of DNA replication and functions to “unlink” newly replicated chromosomes to allow for the completion of cell division.

Inhibition of these enzymes by levofloxacin likely occurs via complexation with the topoisomerase enzymes. The end result is a blockade of DNA replication, thus inhibiting cell division and resulting in cell death.

Pyrazinamide diffuses into active M. tuberculosis that express pyrazinamidase enzyme that converts pyrazinamide to the active form pyrazinoic acid. Pyrazinoic acid can leak out under acidic conditions to be converted to the protonated conjugate acid, which is readily diffused back into the bacilli and accumulate intracellularly. The net effect is that more pyrazinoic acid accumulates inside the bacillus at acid pH than at neutral pH. Pyrazinoic acid was thought to inhibit the enzyme fatty acid synthase (FAS) I, which is required by the bacterium to synthesise fatty acids. However, this theory was thought to have been discounted. However, further studies reproduced the results of FAS I inhibition as the putative mechanism first in whole cell assay of replicating M. tuberculosis bacilli which have shown that pyrazinoic acid and its ester inhibit the synthesis of fatty acids. This study was followed by in vitro assay of tuberculous FAS I enzyme that tested the activity with pyrazinamide, pyrazinoic acid and several classes of pyrazinamide analogs. Pyrazinamide and its analogs inhibited the activity of purified FAS I.

It has also been suggested that the accumulation of pyrazinoic acid disrupts membrane potential and interferes with energy production, necessary for survival of M. tuberculosis at an acidic site of infection. Pyrazinoic acid has also been shown to bind to the ribosomal protein S1 (RpsA) and inhibit trans-translation. This may explain the ability of the drug to kill dormant mycobacteria.

Rifampin acts via the inhibition of DNA-dependent RNA polymerase, leading to a suppression of RNA synthesis and cell death.

Dosage

Adult:

• Active tuberculosis: 5 mg/kg/day. Max: 300 mg/day or 15 mg/kg up to 900 mg/day, 2 or 3 times wkly.
• Latent tuberculosis: 300 mg/day for 6 mth. Nontuberculous mycobacterial infections 5 mg/kg/day for at least 12 mth of culture-negative sputum. Max: 300 mg/day.

Child:10-15 mg/kg/day, max 300 mg/day q 12-24 hourlyWith directly observed biweekly therapy, dosage is 20-30 mg/kg, max 900 mg/dose twice weekly

Acute sinusitis: 500 mg once daily for 10-14 days or 750 mg once daily for 5 days

Exacerbation of chronic bronchitis: 500 mg once daily for 7 days

Community acquired pneumonia: 500 mg once daily for 7-14 days or750 mg once daily for 5 days

Nosocomial pneumonia: 750 mg once daily for 7-14 days

Uncomplicated urinary tract infections: 250 mg once daily for 3 days

Complicated urinary tract infections and acute pyelonephritis: 250 mg once daily for 10 days

Complicated urinary tract infections and acute pyelonephritis: 750 mg once daily for 5 days

Uncomplicated skin and skin structure infections: 500 mg once daily for 7-10 daysComplicated skin and skin structure infections: 750 mg once daily for 7-14 days

Chronic bacterial prostatitis: 500 mg once daily for 28 days

Levofloxacin solution for infusion is administered by slow intravenous infusion once or twice daily. The dosage depends on the type and severity of the infection and the sensitivity of the causative pathogen. The duration of treatment varies according to the severity of the disease.Adult:

• Community-acquired pneumonia: 500 mg once or twice daily,
• Complicated urinary tract infections (including pyelonephritis): 250 mg once daily,
• Chronic bacterial prostatitis: 500 mg once daily,
• Skin and soft tissue infections: 500 mg twice daily
• Enteric fever: 500 mg once daily.

Children:

Levofloxacin can be used in children aged as low as 6 months. The usual dose for children in community acquired pneumonia is:

• Children aged 6 months to less than 5 years: 10 mg/kg b.i.d. (up to 500 mg per day) for 10 days,
• Children aged 5 years to 16 years: 10 mg/kg q.d. (up to 500 mg per day) for 10 days.

The usual dose for children in recurrent or persistent Acute Otitis Media is:

• Children aged 6 months to less than 5 years: 10 mg/kg per day (maximum dose: 500 mg/day) given twice daily for 10 days.

Paediatric Use: Levofloxacin is not recommended for children less than 6 (six) months of age.

Levofloxacin ophthalmic solution:

• Days 1 through 3: Instill one to two drops in the affected eye(s) every 30 minutes to 2 hours while awake and approximately 4 and 6 hours after retiring.
• Day 4 through treatment completion: Instill one to two drops in the affected eye(s) every 1 to 4 hours while awake.

0.5%ophthalmic solution:

• Days 1 and 2: Instill one to two drops in the affected eye(s) every 2 hours while awake, up to 8 times per day.
• Days 3 through 7: Instill one to two drops in the affected eye(s) every 4 hours while awake, up to 4 times per day.

Usual Adult Dose for Tuberculosis: Active:

15 to 30 mg/kg (up to 2 g) orally once a day in combination with three other antituberculous drugs for the initial 2 months of a 6-month or 9-month treatment regimen, until drug susceptibility tests are known. An alternate dosing regimen of 50 to 75 mg/kg (up to 3 g) orally twice a week may be used after 2 weeks of daily therapy to increase patient compliance.

Alternatively, the CDC, The American Thoracic Society, and the Infectious Diseases Society of America suggest the following dosing based on estimated lean body weight:

Daily dosing:

• 40 to 45 kg: 1000 mg
• 56 to 75 kg: 1500 mg
• 76 to 90 kg: 2000 mg

Twice weekly dosing:

• 40 to 55 kg: 2000 mg
• 56 to 75 kg: 3000 mg
• 76 to 90 kg: 4000 mg

Thrice weekly dosing:

• 40 to 55 kg: 1500 mg
• 56 to 75 kg: 2500 mg
• 76 to 90 kg: 3000 mg

Usual Adult Dose for Tuberculosis: Latent:

A public health expert should be consulted prior to the use of the combination regimen with rifampin.

15 to 20 mg/kg, based on actual body weight (lean), orally once daily (maximum 2 g) for 2 months. Alternatively, a dosage of 50 mg/kg may be administered orally twice-weekly (maximum 4 g).

Usual Pediatric Dose for Tuberculosis: Active:

(Used as part of a multidrug regimen. Treatment regimens consist of an initial 2-month phase, followed by a continuation phase of 4 or 7 additional months. Frequency of dosing may differ depending on phase of therapy)

Infants, Children less than 40 kg and Adolescents 14 years and younger and less than 40 kg:Non-HIV patients:

• Daily therapy: 15 to 30 mg/kg/dose (maximum: 2 g/dose) once daily
• Directly observed therapy (DOT): 50 mg/kg/dose (maximum: 2 g/dose) twice weekly

HIV-exposed/infected patients:

• Daily therapy: 20 to 40 mg/kg/dose once daily (maximum: 2 g/day)

Rifampin can be administered by the oral route or by IV infusion. IV doses are the same as those for oral.

Tuberculosis:

• Adults: 10 mg/kg, in a single daily administration, not to exceed 600 mg/day, oral or IV
• Pediatric Patients: 10–20 mg/kg, not to exceed 600 mg/day, oral or IV

It is recommended that oral rifampin be administered once daily, either 1 hour before or 2 hours after a meal with a full glass of water.

Rifampin is indicated in the treatment of all forms of tuberculosis. A three-drug regimen consisting of rifampin, isoniazid, and pyrazinamide is recommended in the initial phase of shortcourse therapy which is usually continued for 2 months. The Advisory Council for the Elimination of Tuberculosis, the American Thoracic Society, and theCenters for Disease Control and Preventionrecommend that either streptomycin or ethambutol be added as a fourth drug in a regimen containing isoniazid (INH), rifampin and pyrazinamide for initial treatment of tuberculosis unless the likelihood of INH resistance is very low. The need for a fourth drug should be reassessed when the results of susceptibility testing are known. If community rates of INH resistance are currently less than 4%, an initial treatment regimen with less than four drugs may be considered.

Following the initial phase, treatment should be continued with rifampin and isoniazid for at least 4 months. Treatment should be continued for longer if the patient is still sputum or culture positive, if resistant organisms are present, or if the patient is HIV positive.

Administration of Levofloxacin (solution for infusion) should be continued for a minimum of 48 to 72 hours after the patient has become febrile or evidence of bacterial eradication has been obtained. Levofloxacin solution for infusion is only intended for slow intravenous infusion; it is administered once or twice daily. The infusion time must be at least 30 minutes for 250 mg or 60 minutes for 500 mg Levofloxacin solution for infusion. It is possible to switch from an initial intravenous application to the oral route at the same dosage after a few days.

Should be taken on an empty stomach. Best taken on an empty stomach 1 hr before or 2 hr after meals.

Preparation Of Solution For IV Infusion: Reconstitute the lyophilized powder by transferring 10 mL of sterile water for injection to a vial containing 600 mg of rifampin for injection. Swirl vial gently to completely dissolve the antibiotic. The reconstituted solution contains 60 mg rifampin per mL and is stable at room temperature for up to 30 hours. Prior to administration, withdraw from the reconstituted solution a volume equivalent to the amount of rifampin calculated to be administered and add to 500 mL of infusion medium. Mix well and infuse at a rate allowing for complete infusion within 3 hours. Alternatively, the amount of rifampin calculated to be administered may be added to 100 mL of infusion medium and infused in 30 minutes.

Dilutions in dextrose 5% for injection (D5W) are stable at room temperature for up to 8 hours and should be prepared and used within this time. Precipitation of rifampin from the infusion solution may occur beyond this time. Dilutions in normal saline are stable at room temperature for up to 6 hours and should be prepared and used within this time. Other infusion solutions are not recommended.

Side Effects

Peripheral neuropathy (dose-related incidence, 10-20% incidence with 10 mg/kg/d), Loss of appetite, Nausea, Vomiting, Stomach pain, Weakness 1-10%, Dizziness, Slurred speech, Lethargy, Progressive liver damage (increases with age; 2.3% in pts > 50 yo), Hyperreflexia, Agranulocytosis, Anemia, Megaloblastic anemia, Thrombocytopenia, Systemic lupus erythematosus, Seizure

The most frequently reported adverse events were headache and a taste disturbance following instillation. Other adverse events included decreased/blurred vision, diarrhea, dyspepsia, fever, infection, instillation site irritation/discomfort, ocular infection, nausea, ocular pain/discomfort, and throat irritation.

General: Fever, porphyria and dysuria have rarely been reported. Gout.

Gastrointestinal: The principal adverse effect is a hepatic reaction. Hepatotoxicity appears to be dose related, and may appear at any time during therapy. GI disturbances including nausea, vomiting and anorexia have also been reported.

Hematologic and Lymphatic: Thrombocytopenia and sideroblastic anemia with erythroid hyperplasia, vacuolation of erythrocytes and increased serum iron concentration have occurred rarely with this drug. Adverse effects on blood clotting mechanisms have also been rarely reported.

Other: Mild arthralgia and myalgia have been reported frequently. Hypersensitivity reactions including rashes, urticaria, and pruritis have been reported. Fever, acne, photosensitivity, porphyria, dysuria and interstitial nephritis have been reported rarely.

Facial flushing and itching, with or without a rash, flu-like syndrome characterised by episodes of fever, chills, headache, dizziness, bone pain, shortness of breath, and malaise; GI adverse effects (e.g. nausea, vomiting, anorexia, diarrhoea, epigastric distress), pseudomembranous colitis, eosinophilia, leucopenia, haemolytic anaemia; alterations in kidney function and renal failure, menstrual disturbances, oedema, myopathy, muscular weakness; orange-red discolouration of the urine, faeces, sweat, saliva, sputum, tears, and other body fluids; thrombophlebitis, local irritation and inflammation after prolonged IV infusion. Rarely, eye irritation and visual disturbances, anaphylaxis or shock.

Toxicity

LD₅₀ 100 mg/kg (Human, oral). Adverse reactions include rash, abnormal liver function tests, hepatitis, peripheral neuropathy, mild central nervous system (CNS) effects. In vivo, Isoniazid reacts with pyridoxal to form a hydrazone, and thus inhibits generation of pyridoxal phosphate. Isoniazid also combines with pyridoxal phosphate; high doses interfere with the coenzyme function of the latter.

The LD₅₀ following oral administration in mice and rats is 1803 mg/kg and 1478 mg/kg, respectively.

Levofloxacin exhibits low potential for acute toxicity - following a single high dose of levofloxacin in several different test animals (e.g. mice, rats, monkeys) observed symptoms included ataxia, ptosis, decreased motor activity, dyspnea, tremors, and convulsions. Treatment of acute overdosage should involve stomach emptying (e.g. with activated charcoal) and general supportive measures. Consider monitoring of the patient's ECG to ensure QTc values remain within range. Levofloxacin is not efficiently removed by dialysis (peritoneal or hemodialysis) and is therefore of little benefit in cases of overdose.

Side effects include liver injury, arthralgias, anorexia, nausea and vomiting, dysuria,malaise and fever, sideroblastic anemia, adverse effects on the blood clotting mechanism or vascular integrity, and hypersensitivity reactions such as urticaria, pruritis and skin rashes.

LD₅₀=1570 mg/kg (rat), chronic exposure may cause nausea and vomiting and unconsciousness

Precaution

Renal or hepatic impairment; convulsive disorders; history of psychosis; patients at risk of neuropathy or pyridoxine deficiency eg, diabetic, alcoholic, malnourished, uraemic, infected with HIV. Careful monitoring of hepatic function is necessary for black and hispanic women. Check hepatic function before and during treatment. Pregnancy and lactation.

The following measures should be taken during administration of Levofloxacin: While taking Levofloxacin adequate amount of water should be drunk to avoid risk of crystalluria. Dose adjustment should be exercised during Levofloxacin ingestion in presence of renal insufficiency & hepatic insufficiency.

While taking Levofloxacin adequate amount of water should be drunk to avoid risk of crystalluria. Dose adjustment should be exercised during Levofloxacin ingestion in presence of renal insufficiency & hepatic insufficiency.

Infusion of fluid should be immediately discontinued if rigor arises for any reason during the process. Do not use if the solution is cloudy, contains particles or after expiry date.

If an allergic reaction to levofloxacin occurs, discontinue the drug. Serious acute hypersensitivity reactions may require immediate emergency treatment. Oxygen and airway management should be administered as clinically indicated.

Prolonged use may result in overgrowth of non-susceptible organisms, including fungi. If superinfection occurs, discontinue use and institute alternative therapy. Patients should be advised not to wear contact lenses if they have signs and symptoms of corneal ulcer. Avoid contaminating the applicator tip with material from the eye, fingers or other source.

Pyrazinamide is contraindicated in patients with severe hepatic disease and with acute gout.

Patients started on pyrazinamide should have baseline serum uric acid and liver function test results. Liver function should be monitored closely during therapy. Patients with preexisting liver disease or those at increased risk of drug related hepatitis should be monitored closely.

Pyrazinamide should be discontinued and not restarted if signs of hepatocellular damage or hyperuricemia with an acute gouty arthritis appear.

Polyarthralgias have been reported in patients. The pain may respond to aspirin or other nonsteroidal anti-inflammatory agents.

Caution should be used in patients with a history of diabetes mellitus, as management of the disease may be more difficult.

Primary resistance of Mycobacterium tuberculosis to pyrazinamide is not common. In cases with known or suspected drug resistance, in vitro susceptibility tests with recent cultures of Mycobacterium tuberculosis against pyrazinamide and the usual primary drugs should be conducted. There are few reliable in vitro tests for pyrazinamide resistance. A reference laboratory capable of performing these tests must be utilized.

Clinical experience has not identified differences in responses between elderly and younger patients. In general, dose selection for elderly patients should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased renal or hepatic function, and of concomitant disease or other drug therapy.

Rifampicin has been shown to produce liver dysfunction. Fatalities associated with jaundice have occurred in patients with liver disease and in patients taking rifampin with other hepatotoxic agents. Patients with impaired liver function should be given rifampin only in cases of necessity and then with caution and under strict medical supervision. In these patients, careful monitoring of liver function, especially SGPT/ALT and SGOT/AST should be carried out prior to therapy and then every 2 to 4 weeks during therapy. If signs of hepatocellular damage occur, rifampin should be withdrawn.

In some cases, hyperbilirubinemia resulting from competition between rifampin and bilirubin for excretory pathways of the liver at the cell level can occur in the early days of treatment. An isolated report showing a moderate rise in bilirubin and/or transaminase level is not in itself an indication for interrupting treatment; rather, the decision should be made after repeating the tests, noting trends in the levels, and considering them in conjunction with the patient's clinical condition.

Rifampin has enzyme-inducing properties, including induction of delta amino levulinic acid synthetase. Isolated reports have associated porphyria exacerbation with rifampin administration.

Interaction

Inhibit the hepatic metabolism of antiepileptics (e.g. carbamazepine, ethosuximide, primidone, phenytoin), benzodiazepines (e.g. diazepam, triazolam), chlorzoxazone, theophylline, disulfiram, sometimes leading to increased toxicity. Increased metabolism of enflurane, resulting in potentially nephrotoxic levels of fluoride. Increased concentrations and enhanced effects or toxicity of clofazimine, cycloserine and warfarin. Reduced absorption with Al-containing antacids. Increased risk of peripheral neuropathy with zalcitabine and stavudine.

Specific drug interaction studies have not been conducted with this drug. However, the systemic administration of some quinolones has been shown to elevate plasma concentrations of theophylline, interfere with the metabolism of caffeine, and enhance the effects of the oral anticoagulant warfarin and its derivatives, and has been associated with transient elevations in serum creatinine in patients receiving systemic cyclosporine concomitantly.

Antagonises the effect of uricosuric agents (e.g. probenecid, sulfinpyrazone). May reduce the contraceptive effect of oestrogens. May inactivate oral typhoid vaccine. May increase the serum concentration of ciclosporin. May enhance the hepatotoxic effect of rifampicin.

May accelerate the metabolism and reduce the effect of drugs that are metabolised by CYP450 enzymes (e.g. quinidine, phenytoin, theophylline). Decreased concentrations of atovaquone and increased concentrations of rifampicin when taken concomitantly. Concurrent use of ketoconazole and rifampicin may result in decreased serum concentrations of both drugs. May decrease serum concentrations of enalaprilat. Reduced absorption by antacids. Increased risk of hepatotoxicity with halothane or isoniazid.

Volume of Distribution

Levofloxacin is widely distributed in the body, with an average volume of distribution following oral administration between 1.09-1.26 L/kg (~89-112 L). Concentrations in many tissues and fluids may exceed those observed in plasma. Levofloxacin is known to penetrate well into skin tissue, fluids (e.g. blisters), lung tissue, and prostatic tissue, amongst others.

Elimination Route

Readily absorbed following oral administration; however, may undergo significant first pass metabolism. Absorption and bioavailability are reduced when isoniazid is administered with food.

Absorption of levofloxacin following oral administration is rapid and essentially complete, with an oral bioavailability of approximately 99%. Due to its nearly complete absorption, the intravenous and oral formulations of levofloxacin may be interchangeable. The T_max is generally attained 1-2 hours following administration and the C_max is proportional to the given dose - an intravenous dose of 500mg infused over 60 minutes resulted in a C_max of 6.2 ± 1.0 µg/mL whereas a 750mg dose infused over 90 minutes resulted in a C_max of 11.5 ± 4.0 µg/mL. Oral administration with food prolongs the T_max by approximately 1 hour and slightly decreases the C_max, but these changes are not likely to be clinically significant.

Systemic absorption following oral inhalation is approximately 50% lower than that observed following oral administration.

Rapidly and well absorbed from the gastrointestinal tract.

Well absorbed from gastrointestinal tract.

Half Life

Fast acetylators: 0.5 to 1.6 hours. Slow acetylators: 2 to 5 hours.

The average terminal elimination half-life of levofloxacin is 6-8 hours.

9-10 hours (normal conditions)

3.35 (+/- 0.66) hours

Clearance

The average apparent total body clearance of levofloxacin ranges from 8.64-13.56 L/h, and its renal clearance ranges from 5.76-8.52 L/h. The relative similarity of these ranges indicates a small degree of non-renal clearance.

• 0.19 +/- 0.06 L/hr/kg [300 mg IV]
• 0.14 +/- 0.03 L/hr/kg [600 mg IV]

Elimination Route

From 50 to 70 percent of a dose of isoniazid is excreted in the urine within 24 hours.

The majority of administered levofloxacin is excreted unchanged in the urine. Following the administration of a single oral dose of levofloxacin, approximately 87% was eliminated unchanged in the urine within 48 hours and less than 4% was eliminated in the feces within 72 hours.

Approximately 70% of an oral dose is excreted in the urine, mainly by glomerular filtration within 24 hours

Less than 30% of the dose is excreted in the urine as rifampin or metabolites.

Pregnancy & Breastfeeding use

Pregnancy Category C. Animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks

Lactation: distributed into milk but safe for nursing infants

Levofloxacin is not recommended for use during pregnancy or nursing, as the effects on the unborn child or nursing infant are unknown.

Pregnancy Category C. Animal reproduction studies have not been conducted with Pyrazinamide. It is also not known whether Pyrazinamide can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. Pyrazinamide should be given to a pregnant woman only if clearly needed.

Nursing Mothers: Pyrazinamide has been found in small amounts in breast milk. Therefore, it is advised that Pyrazinamide be used with caution in nursing mothers taking into account the risk-benefit of this therapy.

Pregnancy: When administered during the last few weeks of pregnancy, rifampin can cause post natal hemorrhages in the mother and infant for which treatment with vitamin K may be indicated.

Nursing Mothers: Because of the potential for tumorigenicity shown for rifampin in animal studies, a decision should be made whether to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother.

Contraindication

Acute liver disease or history of hepatic damage during INH therapy; hypersensitivity.

Levofloxacin is contraindicated in patients with a history of hypersensitivity to Levofloxacin, quinolone antimicrobial agents, or any other components of this product.

Pyrazinamide is contraindicated in persons:

• With severe hepatic damage.
• Who have shown hypersensitivity to it.
• With acute gout.

Rifampicin is contraindicated in patients with a history of hypersensitivity to rifampin or any of the components, or to any of the rifamycins. Rifampin is contraindicated in patients who are also receiving ritonavir-boosted saquinavir due to an increased risk of severe hepatocellular toxicity.

Rifampin is contraindicated in patients who are also receiving atazanavir, darunavir, fosamprenavir, saquinavir, or tipranavir due to the potential of rifampin to substantially decrease plasma concentrations of these antiviral drugs, which may result in loss of antiviral efficacy and/or development of viral resistance.

Special Warning

Use in Children: From clinical studies, it is evident that Levofloxacin can be used in children aged as low as 6 months.The usual dose for children in community acquired pneumonia (CAP) is-

• Children aged 6 months to less than 5 years: 10 mg/kg b.i.d. (up to 500 mg per day) for 10 days.
• Children aged 5 years to 16 years: 10 mg/kg q.d. (up to 500 mg per day) for 10 days.

The usual dose for children in recurrent or persistent Acute Otitis Media (AOM) is Children aged 6 months to less than 5 years: 10 mg/kg per day (maximum dose: 500 mg/day) given twice daily for 10 days.

Usage in Children: Pyrazinamide regimens employed in adults are probably equally effective in children. Pyrazinamide appears to be well tolerated in children.

Geriatric Use: Clinical studies of Pyrazinamide did not include sufficient numbers of patients aged 65 and over to determine whether they respond differently from younger patients. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic or renal function, and of concomitant disease or other drug therapy.It does not appear that patients with impaired renal function require a reduction in dose. It may be prudent to select doses at the low end of the dosing range, however.

Renal Dose Adjustments: The manufacturer recommends to start therapy at low end of dosage range and monitor patient closely.For the treatment of active tuberculosis, the CDC, ATS, and IDSA recommend against daily dosing. For patients with CrCl less than 30 mL/min or patients receiving hemodialysis the recommended dose is 25 to 35 mg/kg per dose three times per week.

Liver Dose Adjustments: Monitor patients closely.

Dose Adjustments: In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic or renal function, and of concomitant disease or other drug therapy.

If organism is susceptible to isoniazid and rifampin, pyrazinamide is continued for the first 2 months of a 6-month course of therapy (9-months if HIV positive). If primary drug resistance is shown, drug regimens should be adjusted as needed and continued for at least 6 months, or 3 months beyond culture conversion (9 months, or 6 months beyond culture conversion if HIV positive). If multiple-drug resistance is demonstrated, therapy should be continued for 12 to 24 months following culture conversion.

Geriatric Use: Clinical studies of Rifampicin did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. Caution should therefore be observed in using rifampin in elderly patients.

Acute Overdose

Levofloxacin exhibits a low potential for acute toxicity. However, in the events of an acute overdosage, the stomach should be emptied. The patients should be kept under observation and appropriate hydration should be maintained.

Overdosage experience is limited. In one case report of overdose, abnormal liver function tests developed. These spontaneously reverted to normal when the drug was stopped. Clinical monitoring and supportive therapy should be employed. Pyrazinamide is dialyzable.

Nausea, vomiting, abdominal pain, pruritus, headache, and increasing lethargy will probably occur within a short time after ingestion; unconsciousness may occur when there is severe hepatic disease. Transient increases in liver enzymes and/or bilirubin may occur. Brownish-red or orange discoloration of the skin, urine, sweat, saliva, tears, and feces will occur, and its intensity is proportional to the amount ingested.

Liver enlargement, possibly with tenderness, can develop within a few hours after severe overdosage; bilirubin levels may increase and jaundice may develop rapidly. Hepatic involvement may be more marked in patients with prior impairment of hepatic function. Other physical findings remain essentially normal. A direct effect upon the hematopoietic system, electrolyte levels, or acid-base balance is unlikely.

Facial or periorbital edema has also been reported in pediatric patients. Hypotension, sinus tachycardia, ventricular arrhythmias, seizures and cardiac arrest were reported in some fatal cases.

Storage Condition

Store in a cool & dry place, protected from light. Keep out of the reach of children.

Store between 15-30° C.

Store between 15-30° C. Avoid excessive heat and protect from light.

Innovators Monograph