Preloc

Preloc Uses, Dosage, Side Effects, Food Interaction and all others data.

Preloc is a selective beta1-blocker. Preloc reduces or inhibits the agonistic effect on the heart of catecholamines (which are released during physical and mental stress). This means that the usual increase in heart rate, cardiac output, cardiac contractility and blood pressure, produced by the acute increase in catecholamines, is reduced by Preloc. Preloc interferes less with Insulin release and carbohydrate metabolism than do non-selective beta-blockers. Preloc interferes much less with the cardiovascular response to hypoglycaemia than do non-selective beta-blockers.

Administration of metoprolol in normal subjects is widely reported to produce a dose-dependent reduction on heart rate and cardiac output. This effect is generated due to a decreased cardiac excitability, cardiac output, and myocardial oxygen demand. In the case of arrhythmias, metoprolol produces its effect by reducing the slope of the pacemaker potential as well as suppressing the rate of atrioventricular conduction.

The Preloc Atherosclerosis Prevention in Hypertensives (MAPHY) trial showed a significant improvement in sudden cardiac death and myocardial infarction when patients were given with metoprolol as compared with diuretics. As well, in clinical trials performed in 1990, metoprolol reduces mortality and re-infarction in 17% of the individuals when administered chronically after an episode of myocardial infarction.

Trade Name Preloc
Availability Prescription only
Generic Metoprolol
Metoprolol Other Names (RS)-Metoprolol, DL-metoprolol, Metoprolol
Related Drugs amlodipine, aspirin, lisinopril, losartan, furosemide, carvedilol, hydrochlorothiazide, propranolol, clopidogrel, spironolactone
Weight 50mg, 25mg, 100mg
Type Tablet
Formula C15H25NO3
Weight Average: 267.3639
Monoisotopic: 267.183443671
Protein binding

Metoprolol is not highly bound to plasma proteins and only about 11% of the administered dose is found bound. It is mainly bound to serum albumin.

Groups Approved, Investigational
Therapeutic Class Beta-adrenoceptor blocking drugs, Beta-blockers
Manufacturer Opsonin Pharma Ltd
Available Country Bangladesh
Last Updated: September 19, 2023 at 7:00 am
Preloc
Preloc

Uses

ln the management of hypertension and angina pectoris. Cardiac arrhythmias, especially supraventricular tachyarrhythmias. Adjunct to the treatment of hyperthyroidism. Early intervention with Preloc in acute myocardial infarction reduces infarct size and the incidence of ventricular fibrillation. Pain relief may also decrease the need for opiate analgesics. Preloc has been shown to reduce mortality when administered to patients with acute myocardial infarction.

Preloc is also used to associated treatment for these conditions: Angina Pectoris, Atrial Fibrillation, High Blood Pressure (Hypertension), Migraine, Myocardial Infarction, Tachycardia, Supraventricular, Thyroid Crisis, Acute hemodynamically stable Myocardial infarction, Chronic heart failure with reduced ejection fraction (NYHA Class II), Chronic heart failure with reduced ejection fraction (NYHA Class III)

How Preloc works

Preloc is a beta-1-adrenergic receptor inhibitor specific to cardiac cells with negligible effect on beta-2 receptors. This inhibition decreases cardiac output by producing negative chronotropic and inotropic effects without presenting activity towards membrane stabilization nor intrinsic sympathomimetics.

Dosage

Preloc dosage

Oral-

Hypertension: Total daily dosage Preloc 100-400 mg to be given as a single or twice daily dose. The starting dose is 100 mg (two Preloc-50 tablets) per day. This may be increased by 100 mg per day at weekly intervals. lf full control is not achieved using a single daily dose, a b.i.d. regimen should be initiated. Combination therapy with a diuretic or other anti-hypertensive agent may also be considered.

Angina: Usually Preloc 50 mg (one Preloc-50 tablet) to 100 mg (two Preloc-50 tablets) twice or three times daily.

Cardiac arrhythmias: Preloc 50 mg (one Preloc-50 tablet) b.i.d or t.i.d should usually control the condition. It necessary the dose can be increased up to 300 mg per day in divided doses. Following the treatment of an acute arrhythmia with Preloc injection, continuation therapy with Preloc tablets should be initiated 4-6 hours later. The initial oral dose should not exceed 50 mg t.i.d.

Hyperthyroidism: Preloc 50 mg (one Preloc-50 tablet) four times a day.The dose should be reduced as the euthyroid state is achieved.

Myocardial infarction: Orally, therapy should commence 15 minutes after the last injection with 50 mg every 6 hours for 48 hours. Patients who fail to tolerate the full intravenous dose should be given half the suggested oral dose. Maintenance – The usual maintenance dose is 200 mg daily given in divided doses. Elderly’ There are no special dosage requirements in otherwise healthy elderly patients. Signidcant hepatic dysfunction: A reduction in dosage may be necessary.

Injection-

Arrhythmias: By intravenous injection, up to 5 mg at a rate of 1-2 mg/minute, repeated after 5 minutes if necessary, total dose 10-15 mg. 

In surgery: By slow intravenous injection 2-4 mg at induction or to control arrhythmias developing during anaesthesia; 2 mg doses may be repeated to a maximum of 10 mg. 

Myocardial Infarction: Early intervention within 12 hours of infarction, by intravenous injection 5 mg every 2 minutes to a maximum of 15 mg, followed after 15 minutes by 50 mg by mouth every 6 hours for 48 hours; maintenance 200 mg daily in divided doses.

Impaired Renal Function: Dose adjustment is not needed in patients with impaired renal function. 

Impaired Hepatic Function: Dose adjustment is not normally needed in patients suffering from liver cirrhosis because Preloc has low protein binding (5-10%). When there are signs of serious impairment of liver function (e.g. shunt-operated patients), a reduction in dose should be considered. 

Elderly: Dose adjustment is not needed.

Side Effects

Bradycardia, bronchospasm, hypotension, headache, fatigue, sleep & gastro-intestinal disturbances, dizziness, vertigo, visual disturbances etc.

Toxicity

Oral administration of metoprolol to rats presents an LD50 in the range of 3090 to 4670 mg/kg. Cases of overdose have reported bradycardia, hypotension, bronchospasm, and cardiac failure. In the case of an overdose, gastric lavage is recommended followed by specific treatment according to symptoms.

Preloc is not reported to be carcinogenic nor mutagenic nor to impair fertility. The only event registered is the increase of macrophages in pulmonary alveoli and slight biliary hyperplasia. When metoprolol was given for long periods of time on the highest dose, there was evidence of small benign lung tumors.

Precaution

The second or third dose should not be given if the heart rate is <40 beats/minute, the P-R interval is > 0.26 seconds and the systolic blood pressure is <90 mmHg or if there is any aggravation of dyspnoea or cold sweating. Intravenous administration of calcium antagonists of the Verapamil-type should not be given to patients treated with beta-blockers. When treating patients with suspected or definite myocardial infarction, the haemodynamic status of the patient should be carefully monitored after each of the three 5 mg intravenous doses. Use in Pregnancy: As with most medicines, Preloc should not be given during pregnancy and lactation unless its use is considered essential. As with all antihypertensive agents, beta-blockers may cause side effects (e.g. bradycardia) in the foetus and in the newborn and breast-fed infant. Use in Lactation: The amount of Preloc ingested via breast-milk seems to be negligible as regards beta-blocking effect in the infant if the mother is treated with Preloc doses within the normal therapeutic range.

Interaction

Plasma level of Preloc may be raised by co-administration of compounds metabolished by CYP2D6 e.g. Antiarrhythmics, antihistamines, H2 receptor antagonists, antidepressants, antipsychotics and COX-2 inhibitors. The plasma conc. of Preloc is lowered by Rifampicin.

Food Interaction

  • Avoid alcohol.
  • Avoid natural licorice.
  • Take with food.

[Moderate] ADJUST DOSING INTERVAL: The bioavailability of metoprolol may be enhanced by food.



MANAGEMENT: Patients may be instructed to take metoprolol at the same time each day, preferably with or immediately following meals.

Preloc Alcohol interaction

[Moderate]

Many psychotherapeutic and CNS-active agents (e.g., anxiolytics, sedatives, hypnotics, antidepressants, antipsychotics, opioids, alcohol, muscle relaxants) exhibit hypotensive effects, especially during initiation of therapy and dose escalation.

Coadministration with antihypertensives and other hypotensive agents, in particular vasodilators and alpha-blockers, may result in additive effects on blood pressure and orthostasis.

Caution and close monitoring for development of hypotension is advised during coadministration of these agents.

Some authorities recommend avoiding alcohol in patients receiving vasodilating antihypertensive drugs.

Patients should be advised to avoid rising abruptly from a sitting or recumbent position and to notify their physician if they experience dizziness, lightheadedness, syncope, orthostasis, or tachycardia.

Preloc Cholesterol interaction

[Moderate] Beta-adrenergic receptor blocking agents (aka beta-blockers) may alter serum lipid profiles.

Increases in serum VLDL and LDL cholesterol and triglycerides, as well as decreases in HDL cholesterol, have been reported with some beta-blockers.

Patients with preexisting hyperlipidemia may require closer monitoring during beta-blocker therapy, and adjustments made accordingly in their lipid-lowering regimen.

Preloc multivitamins interaction

[Moderate] ADJUST DOSING INTERVAL: Concurrent administration with calcium salts may decrease the oral bioavailability of atenolol and possibly other beta-blockers.

The exact mechanism of interaction is unknown.

In six healthy subjects, calcium 500 mg (as lactate, carbonate, and gluconate) reduced the mean peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) of atenolol (100 mg) by 51% and 32%, respectively.

The elimination half-life increased by 44%.

Twelve hours after the combination, beta-blocking activity (as indicated by inhibition of exercise tachycardia) was reduced compared to that with atenolol alone.

However, during a 4-week treatment in six hypertensive patients, there was no difference in blood pressure values between treatments.

The investigators suggest that prolongation of the elimination half-life induced by calcium coadministration may have led to atenolol cumulation during long-term dosing, which compensated for the reduced bioavailability.

It may help to separate the administration times of beta-blockers and calcium products by at least 2 hours.

Patients should be monitored for potentially diminished beta-blocking effects following the addition of calcium therapy.

Volume of Distribution

The reported volume of distribution of metoprolol is 4.2 L/kg. Due to the characteristics of metoprolol, this molecule is able to cross the blood-brain barrier and even 78% of the administered drug can be found in cerebrospinal fluid.

Elimination Route

When metoprolol is administered orally, it is almost completely absorbed in the gastrointestinal tract. The maximum serum concentration is achieved 20 min after intravenous administration and 1-2 hours after oral administration. The bioavailability of metoprolol is of 100% when administered intravenously and when administered orally it presents about 50% for the tartrate derivative and 40% for the succinate derivative.

The absorption of metoprolol in the form of the tartrate derivative is increased by the concomitant administration of food.

Half Life

The immediate release formulations of metoprolol present a half-life of about 3-7 hours.

Clearance

The reported clearance rate on patients with normal kidney function is 0.8 L/min. In cirrhotic patients, the clearance rate changes to 0.61 L/min.

Elimination Route

Preloc is mainly excreted via the kidneys. From the eliminated dose, less than 5% is recovered unchanged.

Pregnancy & Breastfeeding use

Preloc should not be used in pregnancy or lactating mothers unless the physician considers that the benefit outweighs the possible hazard to the fetus or infant.

Contraindication

2nd or 3rd degree AV block, sick sinus syndrome, hypotension, decompensated heart failure, sinus bradycardia, severe peripheral arterial circulatory disorders, cardiogenic shock, severe asthma and bronchospasm, untreated phaeochromocytoma, Prinzmetal's angina, metabolic acidosis.

Special Warning

Renal Impairment: No dosage adjustment needed.

Hepatic Impairment: Reduce dose.

Acute Overdose

Poisoning due to an overdose of metoprolol may lead to severe hypotension, sinus bradycardia, atrioventricular block, heart failure, cardiogenic shock, cardiac arrest, bronchospasm, impairment of consciousness, coma, nausea, vomiting, cyanosis, hypoglycaemia and, occasionally, hyperkalaemia. The first manifestations usually appear 20 minutes to 2 hours after drug ingestion. Treatment: Treatment should include close monitoring of cardiovascular, respiratory and renal function, and blood glucose and electrolytes. Further absorption may be prevented by induction of vomiting, gastric lavage or administration of activated-charcoal if ingestion is recent. Cardiovascular complications should be treated symptomatically, which may require the use of sympathomimetic agents (e.g. noradrenaline, metaramionl), atropine or inotropic agents (e.g. dopamine, dobutamine). Temporary pacing may be required for AV block. Glucagon can reverse the effects of excessive B-blockade, given in a dose of 1-10 mg intravenously. Intravenous B2-stimulants e.g. terbutaline may be required to relieve bronchospasm. Preloc cannot be effectively removed by haemodialysis.

Storage Condition

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

Innovators Monograph

You find simplified version here Preloc

Preloc contains Metoprolol see full prescribing information from innovator Preloc Monograph, Preloc MSDS, Preloc FDA label

FAQ

What is Preloc used for?

Preloc is a beta-blocker that affects the heart and circulation. Preloc is used to treat angina and hypertension. Metoprolol is also used to lower your risk of death or needing to be hospitalized for heart failure. Preloc is used to treat high blood pressure, chest pain due to poor blood flow to the heart, and a number of conditions involving an abnormally fast heart rate.

How safe is Preloc?

Preloc is generally safe to take for a long time. In fact, it works best when you take it for a long time. 

How does Preloc work?

Preloc works by changing the way your body responds to some nerve impulses, especially in the heart.

Is Preloc safe during pregnancy?

A small number of pregnant women specifically taking Preloc have been studied, with no concerns raised that its use causes birth defects or preterm birth. Preloc belongs to a family of medicines called beta blockers.

Is Preloc safe during breastfeeding?

Because of the low levels of Preloc in breastmilk, amounts ingested by the infant are small and would not be expected to cause any adverse effects in breastfed infants. Studies on the use of Preloc during breastfeeding have found no adverse reactions in breastfed infants. No special precautions are required

What are the common side effects of Preloc?

The main side effects of Preloc are headaches, and feeling dizzy, sick or tired these are usually mild and short-lived.

Can I drink alcohol with Preloc?

Avoid drinking alcohol, which could increase drowsiness and dizziness while you are taking Preloc.

Can I drive after taking Preloc?

Do not drive if you think your driving ability is being compromised by Preloc.

When is the best time to take Preloc?

Your doctor may advise you to take your first dose before bedtime because it could make you feel dizzy. If you do not feel dizzy after the first dose, take Preloc in the morning. If you have Preloc more than once a day, try to space the doses evenly throughout the day.

How often can I take Preloc?

Preloc is usually taken once or twice a day, but sometimes it's prescribed to be taken up to 4 times a day.

Can I take Preloc on an empty stomach?

You can take Preloc with or without food, but it's best to do the same each day. Swallow the tablets whole with a drink of water.

How long does Preloc take to work?

Preloc starts to work after about 2 hours, but it can take up to 1 week to fully take effect.

How long does Preloc stay in my system?

Preloc has a half-life of between 3 and 7 hours. This means that after 3 to 7 hours, half of a dose of the drug has been eliminated from your body.

Can I take Preloc for a long time?

Take this medicine only as directed by your doctor. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered. Your dose may need to be changed several times in order to find out what works best for you.

How good is Preloc for blood pressure?

Preloc has an average rating of 5.2 out of 10 from a total of 228 ratings for the treatment of High Blood Pressure.

Can Preloc cause weight gain?

Yes. Weight gain can occur as a side effect of some beta blockers.

What happens if I suddenly stop taking Preloc?

Stopping Preloc suddenly can exacerbate angina and may increase the risk of a heart attack. Reduce dosage gradually over a few weeks as instructed by your doctor.

Who should not take Preloc?

May not be suitable for some people including those with heart block greater than 1st degree, pheochromocytoma, poor circulation, sick sinus syndrome, a thyroid disorder, overt or decompensated heart failure, or who are under the age of 18. Should be used with caution in people with pre-existing respiratory disease.

What happen If I missed Preloc?

If you miss doses not taking Preloc every day, skipping days, or taking doses at different times of day also come with risks. Your blood pressure might fluctuate too often. That might increase your risk for a heart attack.

What happens if I take too many Preloc?

Taking too much Preloc can slow down your heart rate and make it difficult to breathe. It can also cause dizziness and trembling. The amount of metoprolol that can lead to an overdose varies from person to person.


What happen If I stop taking Preloc?

Stopping Preloc suddenly can exacerbate angina and may increase the risk of a heart attack. Reduce dosage gradually over a few weeks as instructed by your doctor. 

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