Propranolol with Chlorpromazine Interaction Details

Brand Names Associated with Propranolol

Brand Names Associated with Chlorpromazine

Medical Content Editor Dr. Brian Staiger, PharmD
Last updated Nov 15, 2023

Interaction Effect

Increased propranolol and chlorproMAZINE exposure, and increased risk of chlorproMAZINE toxicity

Interaction Summary

Coadministration of chlorproMAZINE and propranolol results in increased plasma levels of both drugs, with propranolol levels increasing by 70% . Propranolol administered concomitantly with chlorproMAZINE has induced additive hypotensive effects and grand mal seizures. It has been reported that 6 of 10 patients had their chlorproMAZINE levels increased by 5-fold while on propranolol .

Severity

Moderate

Onset

Delayed

Evidence

Probable

How To Manage Interaction

Coadministration of chlorproMAZINE and propranolol results in increased plasma levels of both drugs, with propranolol levels increasing by 70% .

Mechanism Of Interaction

Decreased chlorproMAZINE and propranolol metabolism

Literature Reports

A) Propranolol administered concomitantly to a patient stabilized on chlorproMAZINE and thiothixene resulted in delirium and grand mal seizures. A 29-year-old female receiving chlorproMAZINE 800 mg/day plus thiothixene 6 mg at bedtime was administered propranolol increasing incrementally to 1200 mg/day over 16 days. Propranolol treatment was discontinued after the patient experienced drowsiness, anxiety, confusion, visual, tactile, and olfactory hallucinations, and a grand mal seizure. Blood chemistry, head CT, and EEG were all normal. In a few days all symptoms subsided and her behavior was normal .

B) In a study involving ten hospitalized chronic patients with schizophrenia, plasma levels of chlorproMAZINE were consistently and significantly elevated during concurrent treatment with propranolol. The study involved two 7-week treatment phases, separated by one week. ChlorproMAZINE was given three times daily for one 7-week period, and was given in combination with propranolol twice daily in the other phase. The mean chlorproMAZINE dose was 6.7 mg/kg and the mean maximum dose of propranolol was 8.1 mg/kg. Results showed that when propranolol was given in addition to chlorproMAZINE, there was a statistically significant increase in plasma levels of chlorproMAZINE parent compound and chlorproMAZINE sulfoxide. There was also an associated increase in serum prolactin levels .

C) Five subjects were placed on propranolol 80 mg orally every eight hours for at least three days, and then were injected with 40 uCi of H3-propranolol. Blood samples were drawn, and subjects were then given chlorproMAZINE 50 mg every eight hours together with propranolol for three to four more days, when H3-propranolol was again injected. Results showed that when chlorproMAZINE was introduced, propranolol plasma levels rose, apparent oral clearance (intrinsic clearance) decreased, hepatic blood flow was unchanged, and systemic clearance was reduced. This interaction is of more academic importance than clinical importance, since propranolol possesses little dose-related toxicity .

Propranolol Overview

• Propranolol is used to treat high blood pressure, irregular heart rhythms, pheochromocytoma (tumor on a small gland near the kidneys), certain types of tremor, and hypertrophic subaortic stenosis (a heart muscle disease). It is also used to prevent angina (chest pain), migraine headaches, and to improve survival after a heart attack. Propranolol is in a class of medications called beta blockers. It works by relaxing blood vessels and slowing heart rate to improve blood flow and decrease blood pressure.

• High blood pressure is a common condition and when not treated, can cause damage to the brain, heart, blood vessels, kidneys and other parts of the body. Damage to these organs may cause heart disease, a heart attack, heart failure, stroke, kidney failure, loss of vision, and other problems. In addition to taking medication, making lifestyle changes will also help to control your blood pressure. These changes include eating a diet that is low in fat and salt, maintaining a healthy weight, exercising at least 30 minutes most days, not smoking, and using alcohol in moderation.

Chlorpromazine Overview

• Chlorpromazine is used to treat the symptoms of schizophrenia (a mental illness that causes disturbed or unusual thinking, loss of interest in life, and strong or inappropriate emotions) and other psychotic disorders (conditions that cause difficulty telling the difference between things or ideas that are real and things or ideas that are not real) and to treat the symptoms of mania (frenzied, abnormally excited mood) in people who have bipolar disorder (manic depressive disorder; a condition that causes episodes of mania, episodes of depression, and other abnormal moods). Chlorpromazine is also used to treat severe behavior problems such as explosive, aggressive behavior and hyperactivity in children 1 to 12 years of age. Chlorpromazine is also used to control nausea and vomiting, to relieve hiccups that have lasted one month or longer, and to relieve restlessness and nervousness that may occur just before surgery. Chlorpromazine is also used to treat acute intermittent porphyria (condition in which certain natural substances build up in the body and cause stomach pain, changes in thinking and behavior, and other symptoms). Chlorpromazine is also used along with other medications to treat tetanus (a serious infection that may cause tightening of the muscles, especially the jaw muscle). Chlorpromazine is in a class of medications called conventional antipsychotics. It works by changing the activity of certain natural substances in the brain and other parts of the body.

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Definitions

Severity Categories

Contraindicated

These drugs, generally, should not be used together simultaneously due to the high risk of severe adverse effects. Combining these medications can lead to dangerous health outcomes and should be strictly avoided unless otherwise instructed by your provider.

Major

This interaction could result in very serious and potentially life-threatening consequences. If you are taking this drug combination, it is very important to be under close medical supervision to minimize severe side effects and ensure your safety. It may be necessary to change a medication or dosage to prevent harm.

Moderate

This interaction has the potential to worsen your medical condition or alter the effectiveness of your treatment. It's important that you are monitored closely and you potentially may need to make adjustments in your treatment plan or drug dosage to maintain optimal health.

Minor

While this interaction is unlikely to cause significant problems, it could intensify side effects or reduce the effectiveness of one or both medications. Monitoring for changes in symptoms and your condition is recommended, and adjustments may be made if needed to manage any increased or more pronounced side effects.

Onset

Rapid: Onset of drug interaction typically occurs within 24 hours of co-administration.

Delayed: Onset of drug interaction typically occurs more than 24 hours after co-administration.

Evidence

Level of documentation of the interaction.

Established: The interaction is documented and substantiated in peer-reviewed medical literature.

Theoretical: This interaction is not fully supported by current medical evidence or well-documented sources, but it is based on known drug mechanisms, drug effects, and other relevant information.

How To Manage The Interaction

Provides a detailed discussion on how patients and clinicians can approach the identified drug interaction as well as offers guidance on what to expect and strategies to potentially mitigate the effects of the interaction. This may include recommendations on adjusting medication dosages, altering the timing of drug administration, or closely monitoring for specific symptoms.

It's important to note that all medical situations are unique, and management approaches should be tailored to individual circumstances. Patients should always consult their healthcare provider for personalized advice and guidance on managing drug interactions effectively.

Mechanism Of Interaction

The theorized or clinically determined reason (i.e., mechanism) why the drug-drug interaction occurs.

Disclaimer: The information provided on this page is for informational purposes only and should not be considered medical advice. Always consult with a qualified healthcare professional regarding your specific circumstances and medical conditions.

Where Does Our Information Come From?

Information for our drug interactions is compiled from several drug compendia, including:

• Gold Standard Drug Database
• Micromedex
• Lexicomp
• DrugBank

The prescribing information for each drug, as published on DailyMED, is also used. 

Individual drug-drug interaction detail pages contain references specific to that interaction. You can click on the reference number within brackets '[]' to see what reference was utilized.

The information posted is fact-checked by HelloPharmacist clinicians and reviewed quarterly.