PROPRANOLOL HYDROCHLORIDE INJECTION USP

Rx ONLY

Propranolol Hydrochloride Injection USP is a synthetic beta-adrenergic receptor blocking agent chemically described as 1-(Isopropylamino)-3-(1-naphthyloxy)-2-propanol hydrochloride. Its structural formula is:

Molecular Formula: C₁₆H₂₁NO₂•HCl

Propranolol hydrochloride is a stable, white, crystalline solid which is readily soluble in water and ethanol. Its molecular weight is 295.80.

Propranolol Hydrochloride Injection USP is available as a 1 mg/mL sterile injectable solution for intravenous administration. Each mL contains 1 mg of propranolol hydrochloride in Water for Injection. The pH is adjusted with citric acid. pH range is 2.8 to 4.0.

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.

At doses greater than required for beta blockade, propranolol also exerts a quinidine-like or anesthetic-like membrane action, which affects the cardiac action potential. The significance of the membrane action in the treatment of arrhythmias is uncertain.

The effects of propranolol are due to selective blockade of beta-adrenergic receptors, leaving alpha-adrenergic responses intact. There are two well-characterized subtypes of beta receptors (beta₁ and beta₂); propranolol interacts with both subtypes equally. Beta₁-adrenergic receptors are found primarily in the heart. Blockade of cardiac beta₁-adrenergic receptors leads to a decrease in the activity of both normal and ectopic pacemaker cells and a decrease in A-V nodal conduction velocity. All of these actions can contribute to antiarrhythmic activity and control of ventricular rate during arrhythmias. Blockade of cardiac beta₁-adrenergic receptors also decreases the myocardial force of contraction and may provoke cardiac decompensation in patients with minimal cardiac reserve.

Beta₂-adrenergic receptors are found predominantly in smooth muscle—vascular, bronchial, gastrointestinal and genitourinary. Blockade of these receptors results in constriction. Clinically, propranolol may exacerbate respiratory symptoms in patients with obstructive pulmonary diseases such as asthma and emphysema (see CONTRAINDICATIONS and WARNINGS).

Propranolol's beta blocking effects are attributable to its S(-) enantiomer.

As propranolol concentration increases, so does its beta-blocking effect, as evidenced by a reduction in exercise-induced tachycardia (n=6 normal volunteers).

In a series of 225 patients with supraventricular (n=145), ventricular (n=69), or both (n=11) arrythmias resistant to digitalis, intravenous propranolol hydrochloride was administered in single doses, averaging 1 to 5 mg. Approximately one-quarter of the patients with supraventricular arrhythmias (generally those with sinus or atrial tachycardia) reverted to normal sinus rhythm. About one-half had symptoms ameliorated either by a decrease in ventricular rate or an attenuation of frequency or severity of paroxysmal attacks.

Approximately one-half of patients with ventricular arrhythmias (generally those with frequent PVCs) reverted to normal sinus rhythm or responded with a reduction in ventricular rate.

Similar findings were seen in a series of 25 Bantu patients with atrial fibrillation (n=16), sinus tachycardia (n=5), and multifocal ventricular extrasystoles (n=9).

In another series, 7 of 8 patients with digitalis-related tachyarrhythmia had ventricular rate decreases after intravenous propranolol. Similarly, limited clinical experience has shown that intravenous propranolol will slow the ventricular rate in patients with Wolff-Parkinson-White syndrome or with tachycardia associated with thyrotoxicosis.

Onset of activity is usually within five minutes.

Intravenous administration is usually reserved for life-threatening arrhythmias or those occurring under anesthesia.

• Supraventricular arrhythmias

  Intravenous propranolol is indicated for the short-term treatment of supraventricular tachycardia, including Wolff-Parkinson-White syndrome and thyrotoxicosis, to decrease ventricular rate. Use in patients with atrial flutter or atrial fibrillation should be reserved for arrythmias unresponsive to standard therapy or when more prolonged control is required. Reversion to normal sinus rhythm has occasionally been observed, predominantly in patients with sinus or atrial tachycardia.

• Ventricular tachycardias

  With the exception of those induced by catecholamines or digitalis, propranolol is not the drug of first choice. In critical situations when cardioversion techniques or other drugs are not indicated or are not effective, propranolol may be considered. If, after consideration of the risks involved, propranolol is used, it should be given intravenously in low dosage and very slowly, as the failing heart requires some sympathetic drive for maintenance of myocardial tone (see DOSAGE AND ADMINISTRATION). Some patients may respond with complete reversion to normal sinus rhythm, but reduction in ventricular rate is more likely. Ventricular arrhythmias do not respond to propranolol as predictably as do the supraventricular arrhythmias.

  Intravenous propranolol is indicated for the treatment of persistent premature ventricular extrasystoles that impair the well-being of the patient and do not respond to conventional measures.

• Tachyarrhythmias of digitalis intoxication

  Intravenous propranolol is indicated to control ventricular rate in life-threatening digitalis- induced arrhythmias. Severe bradycardia may occur (see OVERDOSAGE).

• Resistant tachyarrhythmias due to excessive catecholamine action during anesthesia

  Intravenous propranolol is indicated to abolish tachyarrhythmias due to excessive catecholamine action during anesthesia when other measures fail. These arrhythmias may arise because of release of endogenous catecholamines or administration of catecholamines. All general inhalation anesthetics produce some degree of myocardial depression. Therefore, when propranolol is used to treat arrhythmias during anesthesia, it should be used with extreme caution, usually with constant monitoring of the ECG and central venous pressure (see WARNINGS).

Propranolol is contraindicated in 1) cardiogenic shock, 2) sinus bradycardia and greater than first degree block, 3) bronchial asthma, and 4) in patients with known hypersensitivity to propranolol.

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. Although beta-blockers should be avoided in overt congestive heart failure, some have been shown to be highly beneficial when used with close follow-up in patients with a history of failure who are well compensated and are receiving additional therapies, including diuretics as needed. Beta-adrenergic blocking agents do not abolish the inotropic action of digitalis on heart muscle.

In general, patients with bronchospastic lung disease should not receive beta blockers.

Propranolol should be administered with caution in this setting since it may block bronchodilation produced by endogenous and exogenous catecholamine stimulation of beta receptors.

The necessity or desirability of withdrawal of beta-blocking therapy prior to major surgery is controversial. It should be noted, however, that the impaired ability of the heart to respond to reflex adrenergic stimuli in propranolol-treated patients might augment the risks of general anesthesia and surgical procedures.

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. However, such patients may be subject to protracted severe hypotension.

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 diabetes. In these patients, it may be more difficult to adjust the dosage of insulin.

Propranolol therapy, particularly in infants and children, diabetic or not, has been associated with hypoglycemia especially during fasting, as in preparation for surgery.

Hypoglycemia has been reported after prolonged physical exertion and in patients with renal insufficiency.

Beta-adrenergic blockade may mask certain clinical signs of hyperthyroidism. Therefore, abrupt withdrawal of propranolol may be followed by an exacerbation of symptoms of hyperthyroidism, including thyroid storm. Propranolol may change thyroid-function tests, increasing T₄ and reverse T₃ and decreasing T₃.

Beta-adrenergic blockade in patients with Wolff-Parkinson-White syndrome and tachycardia has been associated with severe bradycardia requiring treatment with a pacemaker. In one case this resulted after an initial 5 mg dose of intravenous propranolol.

Propranolol should be used with caution in patients with impaired hepatic or renal function. Propranolol is not indicated for the treatment of hypertensive emergencies.

Beta-adrenergic receptor blockade can cause reduction of intraocular pressure. Patients should be told that propranolol might interfere with the glaucoma screening test. Withdrawal may lead to a return of intraocular pressure.

While taking beta blockers, patients with a history of severe anaphylactic reaction to a variety of allergens may be more reactive to repeated challenge, either accidental, diagnostic, or therapeutic. Such patients may be unresponsive to the usual doses of epinephrine used to treat allergic reaction.

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 a physician's advice. If propranolol therapy is interrupted and exacerbation of angina occurs, it is usually advisable to reinstitute propranolol therapy and take other measures appropriate for the management of angina pectoris. Since coronary artery disease may be unrecognized, it may be prudent to follow the above advice in patients considered at risk of having occult atherosclerotic heart disease who are given propranolol for other indications.

In patients with hypertension, use of propranolol has been associated with elevated levels of serum potassium, serum transaminases and alkaline phosphatase. In severe heart failure, the use of propranolol has been associated with increases in Blood Urea Nitrogen.

Caution should be exercised when propranolol is administered with drugs that have an effect on CYP2D6, 1A2, or 2C19 metabolic pathways. Co-administration of such drugs with propranolol may lead to clinically relevant drug interactions and changes in its efficacy and/or toxicity (see CLINICAL PHARMACOLOGY, Drug Interactions).

In dietary administration studies in which mice and rats were treated with propranolol for up to 18 months at doses of up to 150 mg/kg/day, there was no evidence of drug-related tumorigenesis. On a body surface area basis, this dose in the mouse and rat is, respectively, about equal to and about twice the maximum recommended human oral daily dose (MRHD) of 640 mg propranolol. In a study in which both male and female rats were exposed to propranolol in their diets at concentrations of up to 0.05%, (about 50 mg/kg body weight and less than the MRHD), from 60 days prior to mating and throughout pregnancy and lactation for two generations, there were no effects on fertility. Based on differing results from Ames Tests performed by different laboratories, there is equivocal evidence for a genotoxic effect of propranolol in bacteria ( S. typhimurium strain TA 1538).

Propranolol is excreted in human milk. Caution should be exercised when propranolol is administered to a nursing woman.

Safety and effectiveness of propranolol in pediatric patients have not been established.

Clinical studies of intravenous propranolol did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Elderly subjects have decreased clearance and a longer mean elimination half-life. These findings suggest that dose adjustment of propranolol injection may be required for elderly patients (see CLINICAL PHARMACOLOGY, Special Populations, Geriatric). In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of the decreased hepatic, renal or cardiac function, and of concomitant disease or other drug therapy.

Propranolol is extensively metabolized by the liver. Compared to normal subjects, patients with chronic liver disease have decreased clearance of propranolol, increased volume of distribution, decreased protein-binding and considerable variation in half-life. Consideration should be given to lowering the dose of intravenously administered propranolol in patients with hepatic insufficiency.

In a series of 225 patients, there were 6 deaths (see CLINICAL STUDIES). Cardiovascular events (hypotension, congestive heart failure, bradycardia, and heart block) were the most common. The only other event reported by more than one patient was nausea.

Other adverse events for intravenous propranolol reported during post-marketing surveillance include cardiac arrest, dyspnea, and cutaneous ulcers.

The following adverse events have been reported with use of formulations of sustained- or immediate-release oral propranolol and may be expected with intravenous propranolol.

Cardiovascular: Bradycardia; congestive heart failure; intensification of AV block; hypotension; paresthesia of hands; thrombocytopenic purpura; arterial insufficiency, usually of the Raynaud type.

Central Nervous System: Lightheadedness; mental depression manifested by insomnia, lassitude, weakness, fatigue; reversible mental depression progressing to 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.

Gastrointestinal: Nausea, vomiting, epigastric distress, abdominal cramping, diarrhea, constipation, mesenteric arterial thrombosis, ischemic colitis.

Allergic: Pharyngitis and agranulocytosis, erythematous rash, fever combined with aching and sore throat, laryngospasm and respiratory distress.

Respiratory: Bronchospasm.

Hematologic: Agranulocytosis, nonthrombocytopenic purpura, thrombocytopenic purpura.

Autoimmune: In extremely rare instances, systemic lupus erythematosus has been reported.

Miscellaneous: Alopecia, LE-like reactions, psoriasiform rashes, dry eyes, male impotence, and Peyronie's disease have been reported rarely. Oculomucocutaneous reactions involving the skin, serous membranes and conjunctivae reported for a beta-blocker (practolol) have not been associated with propranolol.

Propanolol is not significantly dialyzable. In the event of overdosage or exaggerated response, the following measures should be employed:

Hypotension and bradycardia have been reported following propranolol overdose and should be treated appropriately. Glucagon can exert potent inotropic and chronotropic effects and may be particularly useful for the treatment of hypotension or depressed myocardial function after a propranolol overdose. Glucagon should be administered as 50 to 150 mcg/kg intravenously followed by continuous drip of 1 to 5 mg/hour for positive chronotropic effect. Isoproterenol, dopamine, or phosphodiesterase inhibitors may also be useful. Epinephrine, however, may provoke uncontrolled hypertension. Bradycardia can be treated with atropine or isoproterenol. Serious bradycardia may require temporary cardiac pacing.

The electrocardiogram, pulse, blood pressure, neurobehavioral status and intake and output balance must be monitored. Isoproterenol and aminophylline may be useful for bronchospasm.

The usual dose is 1 mg to 3 mg administered under careful monitoring, such as electrocardiography and central venous pressure. The rate of administration should not exceed 1 mg (1 mL) per minute to diminish the possibility of lowering blood pressure and causing cardiac standstill. Sufficient time should be allowed for the drug to reach the site of action even when a slow circulation is present. If necessary, a second dose may be given after two minutes. Thereafter, additional drug should not be given in less than four hours. Additional propranolol should not be given when the desired alteration in rate or rhythm is achieved.

Transfer to oral therapy as soon as possible.

Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit.

Propranolol Hydrochloride Injection USP, 1 mg/mL, is supplied as a 1 mL single dose vial in a carton of 10. NDC 55390-003-10.

Manufactured by:                                         Manufactured for:
Ben Venue Laboratories, Inc.                     Bedford Laboratories™
Bedford, OH 44146                                      Bedford, OH 44146

September 2006                                            Div-PNL-P03