Phenoxybenzamine Pharmacology

Phenoxybenzamine

About Phenoxybenzamine

A non-specific, irreversible Adrenergic Alpha blocker, Peripheral vasodilator ,Antihypertensive.

Mechanism of Action of Phenoxybenzamine

The drug exerts its action by producing non equilibrium type of alpha receptor blockade. It undergoes cyclisation inside the body to form a reactive ethyleniminium intermediate which reacts with alpha receptors and other biomolecules to form strong covalent bonds. The alpha blockade develops gradually and progressively decreases peripheral resistance. Partial blockade of 5-HT, histaminergic and cholinergic receptors can occur at higher doses.

Pharmacokinets of Phenoxybenzamine

Absorption: Partially absorbed orally, Distribution: Distributed in to fatty tissues and slowly released. Excretion: Excreted mainly through urine.

Onset of Action for Phenoxybenzamine

1 to 2 hours

Duration of Action for Phenoxybenzamine

3 to 4days

Half Life of Phenoxybenzamine

N/A

Side Effects of Phenoxybenzamine

1.Postural hypotension
2.Reflex tachycardia
3.Nausea
4.Vomiting
5.Miosis
6.Cumulative toxicity
7.Sedation
8.Drowsiness
9.Depression
10.Tiredness
11.Lethargy
12.Dry mouth
13.Nasal congestion
14.Impairment of ejaculation
15.Palpitation
16.Giddiness

Contra-indications of Phenoxybenzamine

1.Hypersensitivity to the drug
2.Cerebro vascular accidents
3.Recovery period during myocardial infarction
4.Porphyria

Special Precautions while taking Phenoxybenzamine

1.Congestive heart failure (CHF)
2.Cerebro vascular disorders
3.Ischaemic heart diseases
4.Cerebral atherosclerosis
5.Coronary atherosclerosis
6.Renal impairment
7.Porphyria
8.Drug have carcinogenic potential
9..Avoid long duration of treatment with the drug
10.Drug may aggravate respiratory diseases

Pregnancy Related Information

Use with caution

Old Age Related Information

Use with caution

Breast Feeding Related Information

Contraindicated

Children Related Information

Use with caution

Indications for Phenoxybenzamine

1.Phaeochromocytoma
2.Secondary shock
3.Peripheral vascular diseases
4.Clonidine withdrawal
5.Cheese reaction

Interactions for Phenoxybenzamine

Phenoxybenzamine may interact with compounds that stimulate both alpha and beta - adrenergic receptors (i.e.adrenaline) to produce an exaggerated hypotensive response and tachycardia. Phenoxybenzamine blocks hyperthermia production by noradrenaline and blocks hypothermia production by reserpine.

Typical Dosage for Phenoxybenzamine

Phaeochromocytoma:
Oral: Starts with 10mg once daily or 12th hourly, and then gradually increase up to 60mg/day or 1 to2mg/kg/day 12th hourly depending up on the response of the patient.
I.V.: 1mg/kg slowly infused over 1 to2 hours along with 200ml normal saline
Children: Starts with 0.2mg/kg, then gradually increase up to 0.4 to 1.2 mg/kg/day in 3 or 4 divided doses
Maximum dose: 10mg/day

Schedule of Phenoxybenzamine

Storage Requirements for Phenoxybenzamine

Store at room temperature in a light resistant tightly closed container

Effects of Missed Dosage of Phenoxybenzamine

Take the missed dose as soon as noticed and if it is the time for next dose then skip the missed dose. Continue the regular schedule. Do not double the dose.

Effects of Overdose of Phenoxybenzamine

Treatment is supportive and symptomatic. To restore the cerebral circulation kept the patient in recumbent position and elevate the legs. Kept the patient flat for one day or more. Use the leg bandages and abdominal binders for shortening the period of disability. In hypotension infuse I.V.levarterol bitartrate.

Home Delivery for Phenoxybenzamine in Your City

Medicine India is just a publishing medium for medicine related information and does not provide services or sales of medicines including phenoxybenzamine.

However, we do publish a comprehensive directory of Pharmacies, Chemists and Druggists in cities all over India. You can use this directory to find the medicine stores in your city (or area) that provide home delivery services for phenoxybenzamine and other medicines and health products. Home delivery services for phenoxybenzamine may be free or they may cost you depending on the pharmacy and the minimum order requirements. It would be best to get this clarified while placing the order.

Please be aware that you should take phenoxybenzamine only if a doctor has recommended or prescribed it. Some or all pharmacies who provide a home delivery service for medicines might insist on a prescription for phenoxybenzamine before they complete the sale. You can get this information while placing the order for phenoxybenzamine with the pharmacy.

Phenoxybenzamine is a generic medicine name and there are several brands available for it. Some of the brands for phenoxybenzamine might be better known than phenoxybenzamine itself. If the pharmacy that's willing to deliver medicines to your home doesn't have phenoxybenzamine in stock, you can ask for one of the branded alternatives for phenoxybenzamine.