Drug information of Propranolol

Propranolol

Drug group:

Propranolol is a beta-blocker. Beta-blockers affect the heart and circulation (blood flow through arteries and veins). Propranolol is used to treat tremors, angina (chest pain), hypertension (high blood pressure), heart rhythm disorders, and other heart or circulatory conditions.
It is also used to treat or prevent heart attack, and to reduce the severity and frequency of migraine headaches.

Mechanism of effect

The mechanism of the antihypertensive effect of Propranolol has not been established. Among the factors that may be involved in contributing to the antihypertensive action include:
(1) decreased cardiac output,
(2) inhibition of renin release by the kidneys, and
(3) diminution of tonic sympathetic nerve outflow from vasomotor centers in the brain.

Pharmacodynamic

Propranolol is a nonselective, beta-adrenergic receptor-blocking agent possessing no other autonomic nervous system activity. It specifically competes with beta-adrenergic receptor-stimulating agents for available receptor sites. When access to beta-receptor sites is blocked by Propranolol, the chronotropic, inotropic, and vasodilator responses to beta-adrenergic stimulation are decreased proportionately.

Pharmacokinetics

Propranolol is highly lipophilic and almost completely absorbed after oral administration. Approximately 90% of circulating Propranolol is bound to plasma proteins (albumin and alpha-1-acid glycoprotein).
Propranolol crosses the blood-brain barrier and the placenta, and is distributed into breast milk. Propranolol is extensively metabolized in liver with most metabolites appearing in the urine. Half life: 4 hours.

Dosage

Usual Adult Dose for Hypertension Initial dose: Immediate-release:
40 mg orally 2 times a day
Sustained-release: 80 mg orally once a day
XL sustained-release: 80 mg orally once a day at bed time
Maintenance dose: Immediate-release: 120 to 240 mg orally per day Sustained-release: 120 to 160 mg orally per day XL
sustained-release: 80 to
120 mg orally once a day at bedtime
Maximum dose: IR/SR: 640 mg orally per day
XR: 120 mg orally per day

Alerts

1-There have been reports of exacerbation of angina and, in some cases, myocardial infarction, following abrupt discontinuance of Propranolol therapy. Therefore, when discontinuance of Propranolol is planned, the dosage should be gradually reduced over at least a few weeks, and the patient should be cautioned against interruption or cessation of therapy without the physician's advice.
2-Hypersensitivity reactions, including anaphylactic/anaphylactoid reactions, have been associated with the administration of Propranolol.
3-Cutaneous reactions, including Stevens-Johnson Syndrome, toxic epidermal necrolysis, exfoliative dermatitis, erythema multiforme, and urticaria, have been reported with use of Propranolol.
4-Sympathetic stimulation may be a vital component supporting circulatory function in patients with congestive heart failure, and its inhibition by beta blockade may precipitate more severe failure. In Patients without a History of Heart Failure, continued use of beta-blockers can, in some cases, lead to cardiac failure.
5-Propranolol should be administered with caution in this setting since it may provoke a bronchial asthmatic attack by blocking bronchodilation produced by endogenous and exogenous catecholamine stimulation of beta-receptors.
6-Chronically administered beta-blocking therapy should not be routinely withdrawn prior to major surgery, however the impaired ability of the heart to respond to reflex adrenergic stimuli may augment the risks of general anesthesia and surgical procedures.
7-Beta-adrenergic blockade may prevent the appearance of certain premonitory signs and symptoms (pulse rate and pressure changes) of acute hypoglycemia, especially in labile insulin-dependent diabetics
8-Beta-adrenergic blockade may mask certain clinical signs of hyperthyroidism.
9-Beta-adrenergic blockade in patients with Wolff-Parkinson-White syndrome and tachycardia has been associated with severe bradycardia requiring treatment with a pacemaker.
10-Propranolol should be used with caution in patients with impaired hepatic or renal function.

Points of recommendation

1-Take propranolol at the same time each day.
2-Your blood pressure will need to be checked often.
3-If you need surgery, tell the surgeon ahead of time that you are using propranolol. You may need to stop using the medicine for a short time.
4-Propranolol is only part of a complete program of treatment for hypertension that may also include diet, exercise, and weight control. Follow your diet, medication, and exercise routines very closely if you are being treated for hypertension.

Pregnancy level

C


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