Moxonidine

Uses

Moxonidine belongs to a group of drugs called anti-hypertensives that lower blood pressure. Moxonidine is used to treat high blood pressure.

Moxonidine is also used to associated treatment for these conditions: High Blood Pressure (Hypertension)

How Moxonidine works

Stimulation of central alpha 2-adrenergic receptors is associated with sympathoadrenal suppression and subsequent reduction of blood pressure. As this class was further explored it was discovered that sympathoadrenal activity can also be suppressed by a second pathway with a newly discovered drug target specific to imidazolines . Specifically, moxonidine binds the imidazoline receptor subtype 1 (I1) and to a lesser extent αlpha-2-adrenoreceptors in the RSV causing a reduction of sympathetic activity, reducing systemic vascular resistance and thus arterial blood pressure.

Moreover, since alpha-2-adrenergic receptors are considered the primary molecular target that facilitates the most common side effects of sedation and dry mouth that are elicited by most centrally acting antihypertensives, moxonidine differs from these other centrally acting antihypertensives by demonstrating only low affinity for central alpha-2-adrenoceptors compared to the aforementioned I1-imidazoline receptors .

Dosage

Moxonidine dosage

Adults (including the elderly): Your treatment will normally start with one 200 microgram tablet, taken in the morning. After three weeks, your doctor may increase this dose to 400 micrograms daily, given in a single dose in the morning, or in divided doses in the morning and evening. After another three weeks, your doctor may need to increase this dose to 600 micrograms daily, given in divided doses (morning and evening). You should not take more than 400 micrograms as a single dose, or more than 600 micrograms in any one day.

If you forget to take a dose, take one as soon as you remember, unless it is nearly time to take the next one. Do not take a double dose to make up for a forgotten dose.

If you forget to take a dose, take one as soon as you remember, unless it is nearly time to take the next one. Do not take a double dose to make up for a forgotten dose.

Side Effects

The following side effects have been reported at the approximate frequencies shown:

• Very common: dry mouth, drowsiness
• Common: headache, dizziness (vertigo), flushing (vasodilation), weakness or loss of strength, confusion, sleep disturbances, nausea (feeling sick), being sick (vomiting), stomach upsets (dyspepsia), diarrhoea, rash or itching (pruritus), back pain

Toxicity

• Contraindicated due to known hypersensitivity to an ingredient (Physiotens tablets contain lactose), heart failure, severe renal impairment, < 16 years old, >75 years old, bradycardia, severe bradyarrhythmia, sick sinus syndrome, second or third degree atrioventricular block, malignant arrhythmias.
• Used with caution in patients with history of severe coronary artery disease (CAD), unstable angina, angioneurotic edema.
• Pregnancy Category B3:Avoid use during pregnancy (inadequate data in pregnant woman) and lactation (maternal blood stream transfer to breast milk shown) unless benefit clearly justifies risk.
• Lack of specific therapeutic experience in cases of intermittent claudication, Raynaud's disease, Parkinson's disease, epileptic disorders, gluacoma, and depression suggest moxonidine should not be used in such instances .
• Carcinogenicity and genotoxicity does not appear significant.
• Concurrent administration of other hypotensives or sedative and hypnotics can enhance the hypotensive effect and intensify sedation respectively.
• Avoid concurrent Tricyclic Antidepressant (TCA) use to avoid reduction of monoxidine efficacy.
• Generally well tolerated with dry mouth and headache the most common adverse effects
• Symptoms of overdose correlate with pharmacodynamic properties:hypotension, sedation, orthostatic dysregulation, bradycardia, dry mouth with no specific counter-treatment known.

Precaution

Tell your doctor before you start to take this medicine if you:

• have a heart problem called "1st-degree AV-block"
• have a severe coronary heart disease, or have angina (chest pain at rest)
• have poor circulation
• have kidney disease
• have been told you have cerebrovascular insufficiency (poor blood supply to the brain which means you are at a greater risk of stroke)
• are below 16 years of age
• have a rare hereditary problem of galactose intolerance, Lapp lactase deficiency or glucosegalactose malabsorption as you should not take this medicine

Patients who are intolerant to lactose should note that Moxonidine tablets contain a small amount of lactose. If you have been told by your doctor that you have an intolerance to some sugars, contact your doctor before taking this medicinal product.

Interaction

Talk to your doctor if you are taking any of the following:

• beta-blockers, such as propranolol or atenolol, used to treat heart problems
• other medicines used to reduce blood pressure such as furosemide a diuretic, or captopril an angiotensin-converting enzyme inhibitor
• antidepressants such as amitriptyline
• sleeping tablets such as zopiclone, tranquilizers such as nitrazepam, lorazepam or phenobarbital
• Moxonidine is removed from body by kidneys through the process called "tubular excretion". Other medicines removed from the kidneys in the same way could affect how moxonidine works.

Do not drink alcohol whilst taking Moxonidine.

Volume of Distribution

1.8±0.4L/kg.

Elimination Route

90% of an oral dose is absorbed with negligible interference from food intake or first pass metabolism, resulting in a high bioavailability of 88%.

Half Life

Plasma elimination half life is 2.2 - 2.3 hours while renal elimination half life is 2.6-2.8 hours.

Clearance

Administered twice daily due to short half life .

However, lower dosage adjustments and close monitoring is necessary in elderly and renal impairment patients due to reduced clearance. In particular, the exposure AUC can increase by about 50% following a single dose and at steady state in elderly patients and moderately impaired renal function with GFR between 30-60 mL/min can cause AUC increases by 85% and decreases in clearence to 52 %.

Elimination Route

Elimination is nearly entirely via the kidneys with a majority (50 -75%) of overall moxonidine being eliminated unchanged through renal excretion. Ultimately, more than 90% of a dose is eliminated by way of the kidneys within the first 24 hours after administration, with only approximately 1% being eliminiated via faeces.

Pregnancy & Breastfeeding use

Moxonidine is not recommended if you are pregnant, planning on becoming pregnant or are breastfeeding. Ask your doctor or pharmacist for advice before taking any medicine if you are pregnant or breastfeeding.

Contraindication

Do NOT take Moxonidine if you:

• Are allergic (hypersensitive) to moxonidine or any of the other ingredients of this medicine
• Have a slow heart rate or suffer from an abnormal heart rhythm or a change in the rate of the heart beat (called “sick sinus syndrome” or “2nd or 3rd degree AV-block”
• Have, or have had, heart failure or other heart problems

Special Warning

Patients with kidney problems: If you have moderate problems with your kidneys, you should not take more than one 200 microgram tablet as a single dose or more than 400 micrograms in total, a day.

Children under 16 years of age: Moxonidine is not recommended for use in children.

Acute Overdose

If you (or someone else) swallow a lot of the tablets all together, or if you think a child has swallowed any of the tablets, contact your nearest hospital casualty department or your doctor immediately. An overdose is likely to cause headache, sleepiness, dry mouth, loss of balance, dizziness, low blood pressure, slowing of the pulse, vomiting, feeling tired, weakness and pain in your stomach. Please take this leaflet, any remaining tablets and the container with you to the hospital or doctor so that they know which tablets were consumed.

Storage Condition

Do not store above 30° C. Keep blister in the outer carton in order to protect from light

Innovators Monograph

You find simplified version here Moxonidine