"What are beta blockers and how do they work?
Beta blockers, also known as beta-adrenergic blocking agents, are a class of drugs that works by blocking the neurotransmitters norepinephrine and epinephrine from binding to receptors. "...
The following adverse events were observed and have been reported in patients using propranolol.
Central Nervous System: Light-headedness; mental depression manifested by insomnia, lassitude, weakness, fatigue; catatonia; visual disturbances; hallucinations; vivid dreams; an acute reversible syndrome characterized by disorientation for time and place, short-term memory loss, emotional lability, slightly clouded sensorium, and decreased performance on neuropsychometrics. For immediate release formulations, fatigue, lethargy, and vivid dreams appear dose related.
Allergic: Hypersensitivity reactions, including anaphylactic/anaphylactoid reactions; pharyngitis and agranulocytosis; erythematous rash; fever combined with aching and sore throat; laryngospasm; respiratory distress.
Hematologic: Agranulocytosis, nonthrombocytopenic purpura, and thrombocytopenic purpura.
Autoimmune: Systemic lupus erythematosus (SLE).
Skin and mucous membranes: Stevens-Johnson Syndrome, toxic epidermal necrolysis, dry eyes, exfoliative dermatitis, erythema multiforme, urticaria, alopecia, SLE-like reactions, and psoriasisiform rashes. Oculomucocutaneous syndrome involving the skin, serous membranes, and conjunctivae reported for a beta-blocker (practolol) have not been associated with propranolol.
Genitourinary: Male impotence; Peyronie's disease.
Read the Inderal LA (propranolol) Side Effects Center for a complete guide to possible side effects
Caution should be exercised when Inderal LA (propranolol) is administered with drugs that have an affect on CYP2D6, 1A2, or 2C19 metabolic pathways. Co-administration of such drugs with propranolol may lead to clinically relevant drug interactions and changes on its efficacy and/or toxicity (see Drug Interactions in Pharmacokinetics And Drug Metabolism).
Alcohol when used concomitantly with propranolol, may increase plasma levels of propranolol.
Propafenone has negative inotropic and beta-blocking properties that can be additive to those of propranolol.
Quinidine increases the concentration of propranolol and produces greater degrees of clinical beta-blockade and may cause postural hypotension.
Amiodarone is an antiarrhythmic agent with negative chronotropic properties that may be additive to those seen with p-blockers such as propranolol.
The clearance of lidocaine is reduced with administration of propranolol. Lidocaine toxicity has been reported following co-administration with propranolol.
Caution should be exercised when administering Inderal LA (propranolol) with drugs that slow A-V nodal conduction, e.g., lidocaine and calcium channel blockers.
Both digitalis glycosides and beta-blockers slow atrioventricular conduction and decrease heart rate. Concomitant use can increase the risk of bradycardia.
Calcium Channel Blockers
Caution should be exercised when patients receiving a beta-blocker are administered a calcium-channel-blocking drug with negative inotropic and/or chronotropic effects. Both agents may depress myocardial contractility or atrioventricular conduction.
There have been reports of significant bradycardia, heart failure, and cardiovascular collapse with concurrent use of verapamil and beta-blockers.
Co-administration of propranolol and diltiazem in patients with cardiac disease has been associated with bradycardia, hypotension, high degree heart block, and heart failure.
When combined with beta-blockers, ACE inhibitors can cause hypotension, particularly in the setting of acute myocardial infarction.
The antihypertensive effects of clonidine may be antagonized by beta-blockers. Inderal LA (propranolol) should be administered cautiously to patients withdrawing from clonidine.
Prazosin has been associated with prolongation of first dose hypotension in the presence of beta-blockers.
Postural hypotension has been reported in patients taking both beta-blockers and terazosin or doxazosin.
Patients receiving catecholamine-depleting drugs, such as reserpine should be closely observed for excessive reduction of resting sympathetic nervous activity, which may result in hypotension, marked bradycardia, vertigo, syncopal attacks, or orthostatic hypotension.
Patients on long-term therapy with propranolol may experience uncontrolled hypertension if administered epinephrine as a consequence of unopposed alpha-receptor stimulation. Epinephrine is therefore not indicated in the treatment of propranolol overdose (see OVERDOSAGE).
Isoproterenol and Dobutamine
Propranolol is a competitive inhibitor of beta-receptor agonists, and its effects can be reversed by administration of such agents, e.g., dobutamine or isoproterenol. Also, propranolol may reduce sensitivity to dobutamine stress echocardiography in patients undergoing evaluation for myocardial ischemia.
Nonsteroidal Anti-Inflammatory Drugs
Nonsteroidal anti-inflammatory drugs (NSAIDs) have been reported to blunt the antihypertensive effect of beta-adrenoreceptor blocking agents.
Administration of indomethacin with propranolol may reduce the efficacy of propranolol in reducing blood pressure and heart rate.
The hypotensive effects of MAO inhibitors or tricyclic antidepressants may be exacerbated when administered with beta-blockers by interfering with the beta blocking activity of propranolol.
Methoxyflurane and trichloroethylene may depress myocardial contractility when administered with propranolol.
Propranolol when administered with warfarin increases the concentration of warfarin.
Prothrombin time, therefore, should be monitored.
Hypotension and cardiac arrest have been reported with the concomitant use of propranolol and haloperidol.
Thyroxine may result in a lower than expected TS concentration when used concomitantly with propranolol.
Read the Inderal LA Drug Interactions Center for a complete guide to possible interactions
Last reviewed on RxList: 10/12/2010
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