Guanabenz

Guanabenz is an Antihypertensive agent belonging to the Centrally acting alpha-2-adrenergic agonist.

Guanabenz is approved for the treatment of hypertension. It is also used in the treatment of Attention Deficit Disorder and Motor Tic Disorder.

Guanabenz is rapidly absorbed with a bioavailability of approx. 75% through gastrointestinal tract. It is extensively distributed in tissues with plasma protein binding of approx. 90%. Guanabenz undergoes extensive first-pass hepatic metabolism. Its elimination half-life is 7-14 hr, and its renal clearance is 0.09-0.131 l/min. Less than 2% is excreted unchanged in the urine. About 80% of a dose is excreted in the urine in the first 24 hr.

The common side effects associated with Guanabenz include dry mouth, dizziness, headache, constipation, depression, anxiety, fatigue, nausea, vomiting, diarrhea, insomnia, nightmare, sedation, lethargy, irritability, rash, etc.

Guanabenz is available in the form of dosage forms such as a tablet.

Guanabenz is available in Switzerland, India, USA, and Sweden.

Guanabenz, belonging to the centrally acting alpha-2 adrenergic agonist, acts as antihypertensive agent. Guanabenz works by controlling nerve impulses along certain nerve pathways. As a result, it relaxes blood vessels so that the blood passes through them more easily. This helps to lower blood pressure.

Guanabenz antihypertensive action is thought to result from reduce in sympathetic outflow from the brain to the peripheral circulatory system as a result of stimulation of central alpha 2-adrenoceptors.

Guanabenz leads to suppression of sympathetic nervous system activity from bulbar vasoconstriction centers as well as peripheral adrenergic neuron blockade.

The onset of the action of Guanabenz occurs within 60 minutes.

The Duration of Action for Guanabenz is 4-14 hours.

The Tmax was found within 2 hours and Cmax in blood reached 2.4-2.7 ng/ml.

Guanabenz is available in the form of

• Tablets
• Injections for verterinary use.

Guanabenz is taken orally by mouth with or without water.

Guanabenz is approved for the treatment of hypertension. It is also used in the treatment of Attention Deficit Disorder and Motor Tic Disorder.

Guanabenz antihypertensive effect is thought to be due to central alpha-adrenergic stimulation, which results in a reduced sympathetic outflow to the heart, kidneys, and peripheral vasculature in addition to a decreased systolic and diastolic blood pressure and a slight slowing of pulse rate. Chronic administration of guanabenz also causes a reduce in peripheral vascular resistance.

Guanabenz is approved for use in the following clinical indications

Guanabenz is used to treat mild to moderate hypertension.

Initial dose: 4 mg orally twice a day, whether used alone or in combination with a thiazide diuretic.

Maintenance dose: 4 to 8 mg orally twice a day. The maximum dose studied is 32 mg twice a day, although doses this high are rarely needed.

Although not approved, there have been certain off-label uses documented for Guanabenz. These include:

• Attention Deficit Disorder
• Motor Tic Disorder.

The dosage and the duration of treatment should be as per the clinical judgment of the treating physician.

Guanabenz is available in various dosage strength: 4 mg, 8 mg

Guanabenz is available in the form of tablets.

Guanabenz is approved for the treatment of hypertension. It is also used in the treatment of Attention Deficit Disorder and Motor Tic Disorder.

Hypertension: It has been observed that the low-salt Dietary Approaches to Stop Hypertension (DASH) diet lowers blood pressure. Sometimes after a few weeks, its effects on blood pressure become noticeable.

The dietary restriction should be individualized as per the patient's requirements.

Guanabenz is contraindicated in conditions such as allergy and hypersensitivity.

The treating physician must closely monitor the patient and keep pharmacovigilance as follows.

• Before having any kind of surgery (including dental surgery) or emergency treatment, tell the doctor or dentist in charge that you are using guanabenz.
• Do not take other medicines unless they have been discussed with the doctor. This especially includes over-the-counter (non prescription) medicines for appetite control, asthma, colds, cough, hay fever, or sinus problems since they may tend to increase the blood pressure.
• Guanabenz will add to the effects of alcohol and other CNS depressants (medicines that slow down the nervous system, possibly causing drowsiness). Some examples of CNS depressants are antihistamines or medicine for hay fever, other allergies, or colds; sedatives, tranquilizers, or sleeping medicine; prescription pain medicine or narcotics; barbiturates; medicine for seizures; muscle relaxants; or anesthetics, including some dental anesthetics.
• Check with the doctor before taking any of the above while you are using guanabenz. Guanabenz may cause some people to become dizzy, drowsy, or less alert than they are normally. Make sure to know how to react to guanabenz before once drive, use machines, or do anything else that could be dangerous if anyone feels dizzy or are not alert.
• Guanabenz may cause dryness of the mouth, nose, and throat.
• For temporary relief of mouth dryness, use sugarless candy or gum, melt bits of ice in the mouth, or use a saliva substitute. However, if mouth continues to feel dry for more than 2 weeks, check with the medical doctor or dentist. Continuing dryness of the mouth may increase the chance of dental disease, including tooth decay, gum disease, and fungus infections.

Guanabenz and ethanol may have additive effects in lowering your blood pressure.

The adverse reactions related to molecule Guanabenz can be categorized as

• Common Adverse effects:

Hemodynamic compromise, Dizziness, infusion site reaction such as blistering /necrosis/ thrombophlebitis.

• Less Common adverse effects:

Asymptomatic and symptomatic hypotension, burning, crawling, itching, numbness.

• Rare adverse effects:

Bradycardia, decompensated heart failure, cardiac arrest, and heart block.

The clinically relevant drug interactions of Guanabenz is briefly summarized here.

Guanabenz has not been demonstrated to cause any drug interactions when administered with other drugs, such as digitalis, diuretics, analgesics, anxiolytics, and antiinflammatory or antiinfective agents, in clinical trials. However, the potential for increased sedation when Guanabenz is administered concomitantly with CNS-depressant drugs should be noted

Pediatric Use

Safety and effectiveness in pediatric patients have not been established.

Geriatric Use

No overall differences in safety or effectiveness have been observed between elderly and younger patients.

• Overdosage with guanabenz has been reported.
• The main symptoms were lethargy, drowsiness, bradycardia, and hypotension.
• A 45-year-old woman who had taken 200 to 240 mg of guanabenz with alcohol recovered after gastric lavage and intravenous fluids; a 3-year-old child who had taken 12 mg of guanabenz responded to atropine and dopamine.

Pharmacodynamics:

• Guanabenz is an orally active central alpha 2-adrenoceptor agonist. Its antihypertensive action is thought to result from a decrease in sympathetic outflow from the brain to the peripheral circulatory system as a result of stimulation of central alpha 2-adrenoceptors. In mild to moderate hypertension it is as effective as methyldopa and clonidine in lowering blood pressure when used as the sole treatment. As with these drugs, guanabenz may be combined with a diuretic to increase its blood pressure-lowering effect.
• Guanabenz's antihypertensive effect is thought to be due to central alpha-adrenergic stimulation, which results in a decreased sympathetic outflow to the heart, kidneys, and peripheral vasculature in addition to a decreased systolic and diastolic blood pressure and a slight slowing of pulse rate. Chronic administration of guanabenz also causes a decrease in peripheral vascular resistance.

Pharmacokinetics:

• Absorption:

Guanabenz is rapidly absorbed with bioavailability of approx. 75% through gastrointenstinal tract.

• Distribution:

It is extensively distributed in tissues with plasma protein binding of approx. 90%.

• Metabolism:

Guanabenz undergoes extensive first-pass hepatic metabolism.

• Elimination:

Its elimination half-life is 7-14 hr, and its renal clearance is 0.09-0.131 l/min. Less than 2% is excreted unchanged in the urine. About 80% of a dose is excreted in urine in the first 24 hr.

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