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Bretylol Side Effects

Generic name: bretylium

Medically reviewed by Last updated on Apr 19, 2024.

Note: This document contains side effect information about bretylium. Some dosage forms listed on this page may not apply to the brand name Bretylol.

Applies to bretylium: injection solution.

Serious side effects of Bretylol

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

Other side effects of Bretylol

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.

You may report side effects to the FDA at 1-800-332-1088. You may also report side effects at

For Healthcare Professionals

Applies to bretylium: injectable solution, intravenous solution.


Cardiovascular side effects including hypotension have been commonly reported during bretylium (the active ingredient contained in Bretylol) therapy. Hypotension occurs most frequently during intravenous administration. Postural hypotension has also been reported even when administered in a supine position. Other cardiovascular side effects have included transient hypertension, induction of new arrhythmias, bradycardia, precipitation of angina, and substernal pressure sensation. Flushing has been reported.[Ref]

Postural hypotension has occurred in most patients and was usually reversible with volume expansion or catecholamine infusion such as dopamine or epinephrine. It is recommended that patients remain supine until blood pressure changes stabilize. Some degree of supine hypotension occurred in approximately 50% of patients. The degree of hypotension did not appear to be dose-related and discontinuation was usually not required.

Bretylium administration causes an initial release of norepinephrine which may result in increased blood pressure or aggravation of arrhythmias. These effects are usually transient and do not generally require discontinuation of bretylium.[Ref]


Gastrointestinal side effects of nausea and vomiting have occurred with rapid intravenous infusion. Diarrhea has been reported during intravenous and intramuscular administration.[Ref]

To minimize nausea and vomiting due to rapid intravenous infusion, it is recommended that bretylium be diluted in at least 50 cc of 5% dextrose or normal saline and infused over 10 to 15 minutes.[Ref]


Local pain at the site of intramuscular injections has occurred. Administration sites should be rotated to prevent atrophy, fibrosis, or necrosis of muscle tissue, or vascular degeneration and inflammatory changes.[Ref]

Nervous system

Nervous system side effects of headache, sweating, and hyperthermia have occurred.[Ref]

At least two cases of extreme hyperthermia to 108 degrees Fahrenheit have been reported. In both cases, the temperature fell rapidly after bretylium was discontinued and normalized in less than 16 hours. The mechanism for this effect is unknown.[Ref]


Respiratory side effects including shortness of breath and nasal congestion have been reported rarely. A causal relationship between the side effect and the use of bretylium (the active ingredient contained in Bretylol) has not been clearly established.[Ref]


Psychiatric side effects including confusion, anxiety, psychoses, and emotional lability have been reported rarely. A causal relationship between the side effect and the use of bretylium (the active ingredient contained in Bretylol) has not been clearly established.[Ref]


Dermatologic side effects including erythematous macular rash have been reported rarely. A causal relationship between the side effect and the use of bretylium (the active ingredient contained in Bretylol) has not been clearly established.[Ref]


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2. Cohen HC, Gozo EG, Langendorf R, et al. (1973) "Response of resistant ventricular tachycardia to bretylium: relation to site to ectopic focus and location of myocardial disease." Circulation, 47, p. 331-40

3. Chatterjee K, Mandel WJ, Vyden JK, et al. (1973) "Cardiovascular effects of bretylium tosylate in acute myocardial infarction." JAMA, 223, p. 757-60

4. Alfery DD, Denlinger JK (1979) "Profound hypotension following a "test dose" of bretylium tosylate." Anesth Analg, 58, p. 516-8

5. Koch-Weser J (1979) "Bretylium." N Engl J Med, 300, p. 473-7

6. Narang PK, Adir J, Josselson J, Yacobi A, Sadler J (1980) "Pharmacokinetics of bretylium in man after intravenous administration." J Pharmacokinet Biopharm, 8, p. 363-72

7. Anderson JL, Popat KD (1981) "Paradoxical ventricular tachycardia and fibrillation after intravenous bretylium therapy." Arch Intern Med, 141, p. 801-2

8. Bexton RS, Camm AJ (1982) "Drugs with a class III antiarrhythmic action." Pharmacol Ther, 17, p. 315-55

9. Kron IL, Nolan SP (1983) "Severe hypotension due to the use of bretylium for postcardiotomy ventricular arrhythmias." Ann Thorac Surg, 35, p. 271-3

10. Rapeport WG (1985) "Clinical pharmacokinetics of bretylium." Clin Pharmacokinet, 10, p. 248-56

11. Anderson JL (1985) "Bretylium tosylate: profile of the only available class III antiarrhythmic agent." Clin Ther, 7, p. 205-24

12. Duff HJ, Roden DM, Yacobi A, et al. (1985) "Bretylium: relations between plasma concentrations and pharmacologic actions in high-frequency ventricular arrhythmias." Am J Cardiol, 55, p. 395-401

13. Perlman PE, Adams WG, Ridgeway NA (1989) "Extreme pyrexia during bretylium administration." Postgrad Med, 85, 111, 114

14. Bryan CK, Darby MH (1979) "Bretylium tosylate: a review." Am J Hosp Pharm, 36, p. 1189-92

15. Heissenbuttel RH, Bigger JT Jr (1979) "Bretylium tosylate: a newly available antiarrhythmic drug for ventricular arrhythmias." Ann Intern Med, 91, p. 229-38

16. (2002) "Product Information. Bretylol (bretylium)." DuPont Pharmaceuticals

17. Kellog DL, Johnson JM, Kosiba WA (1990) "Baroflex control of the cutaneous active vasodilator system in humans." Circ Res, 66, p. 1420-6

18. Taylor SH, Saxton C, Davies PS, Stoker JB (1970) "Bretylium tosylate in prevention of cardiac dysrhythmias after myocardial infarction." Br Heart J, 32, p. 326-9

19. Day HW, Bacaner M (1971) "Use of bretylium tosylate in the management of acute myocardial infarction." Am J Cardiol, 27, p. 177-89

20. Josselson J, Narang PK, Adir J, Yacobi A, Sadler JH (1983) "Bretylium kinetics in renal insufficiency." Clin Pharmacol Ther, 33, p. 144-50

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.