Sunday, August 18, 2013

PHENOXYBENZAMINE

This medication is used to treat high blood pressure and heavy sweating due to a certain tumor of the adrenal glands (pheochromocytoma). Phenoxybenzamine belongs to a class of drugs known as alpha blockers. It works by relaxing and widening blood vessels so that blood can flow more easily.
OTHER USES: This section contains uses of this drug that are not listed in the approved professional labeling for the drug but that may be prescribed by your health care professional. Use this drug for a condition that is listed in this section only if it has been so prescribed by your health care professional.
This drug may also be used with other medications to treat certain blood circulation problems (e.g., Raynaud's syndrome).
It is also used to treat certain conditions which involve difficulty urinating (e.g., neurogenic bladder, partial prostatic obstruction).

alpha adrenergic blocker   .


(RS)-N-benzyl-N-(2-chloroethyl)-1-phenoxypropan-2-amine

PHARMACOLOGY
Phenoxybenzamine is used as an anti-hypertensive due to its efficacy in reducing the vasoconstriction caused by epinephrine (adrenaline) and norepinephrine. Phenoxybenzamine forms a permanent covalent bond with adrenergic receptors. Based on known information about the structures of these receptors, it likely involves attack by the cysteine at position 3.36 in transmembrane helix 3 to form a stable linkage. Thus, it remains permanently bound to the receptor, preventing adrenaline and noradrenaline from binding. This causes vasodilatation in blood vessels, due to its antagonistic effect at the alpha-1 adrenoceptor found in the walls of blood vessels, resulting in a drop in blood pressure. A side effect of phenoxybenzamine is reflex tachycardia.
It will also affect the postsynaptic alpha 1 and 2 receptors in the nervous system, and so reduce sympathetic activity. This results in further vasodilation, pupil constriction, an increase in GI tract motility and secretions, and glycogen synthesis.
It also has partial agonist/antagonist properties at the serotonin 5-HT2A receptor. Due to its 5-HT2A antagonism, it is useful in the treatment of carcinoid tumor, a neoplasm that secretes large amounts of serotonin and causes diarrhea, bronchoconstriction, and flushing.


DOSE

The dose of phenoxybenzamine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of phenoxybenzamine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

For oral dosage form (capsules):
For high blood pressure caused by pheochromocytoma:
Adults—At first, 10 milligrams (mg) two times a day. Then, your doctor may increase your dose to 20 to 40 mg two or three times a day.
Children—Dose is based on body weight and must be determined by your doctor. The usual starting dose is 0.2 mg per kilogram (kg) (0.09 mg per pound) of body weight taken once a day. Then, your doctor may increase your dose to 0.4 to 1.2 mg per kg (0.18 to 0.55 mg per pound) of body weight a day. This is divided into three or four doses.

Storage

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.
Keep out of the reach of children.
Do not keep outdated medicine or medicine no longer needed.


SPECIAL PRECAUTIONS
tell your doctor and pharmacist if you are allergic to phenoxybenzamine or any other drugs.
tell your doctor and pharmacist what prescription and nonprescription medications you are taking, especially medications for diet control, high blood pressure, asthma, cough, colds, allergies, and glaucoma; and vitamins.
tell your doctor if you have or have ever had heart or kidney disease, a stroke, or transient ischemic attacks (TIA).
tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking phenoxybenzamine, call your doctor immediately.
if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking phenoxybenzamine.
you should know that this drug may make you drowsy. Do not drive a car or operate machinery until you know how this drug affects you.
remember that alcohol can add to the drowsiness caused by this drug.



SIDE EFFECTS

Phenoxybenzamine may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
nasal congestion  , dizziness  , upset stomach  , sexual dysfunction (difficulty ejaculating)  , dizziness

If you experience any of the following symptoms, call your doctor immediately:
fainting  , fast heartbeat    , vomiting

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online [at http://www.fda.gov/Safety/MedWatch] or by phone [1-800-332-1088].




DRUG INTERACTIONS
Using phenoxybenzamine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

Acebutolol
Alprenolol
Atenolol
Betaxolol
Bevantolol
Bisoprolol
Bucindolol
Carteolol
Carvedilol
Celiprolol
Dilevalol
Esmolol
Labetalol
Levobunolol
Mepindolol
Metipranolol
Metoprolol
Nadolol
Nebivolol
Oxprenolol
Penbutolol
Pindolol
Propranolol
Sotalol
Talinolol
Tertatolol
Timolol
Vardenafil

BRANDS

Dibenzyline

China - 2 Results
酚苄明/phenoxybenzamine
酚苄明 - 丽珠制药/Phenoxybenzamine - Livzon  [ 丽珠制药厂 / Livzon Pharm ]
India - 4 Results
BIOPHENOX  [ United Biotech ]
FENOBEN  [ Celon (Revilon) ]
FENOXENE  [ Samarth ]
phenoxybenzamine
Indonesia - 1 Results
phenoxybenzamine
Hong Kong - 1 Results
phenoxybenzamine
Malaysia - 1 Results
phenoxybenzamine
Philippines - 1 Results
phenoxybenzamine
Singapore - 1 Results
phenoxybenzamine
Thailand - 2 Results
Adrenaline Atlantic  [ Atlantic Lab ]   [ Vana ]
phenoxybenzamine
Vietnam - 0 Results
USA - 2 Results
Demser  [ Merck & Co Inc ]
phenoxybenzamine



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