Phenergan vs. Compro for Nausea: Important Differences and Potential Risks.

Key takeaways

Promethazine (Phenergan) and prochlorperazine (Compro) are both prescription medications used to treat nausea and vomiting, but they have some key differences. Promethazine is an antihistamine that also blocks dopamine and acetylcholine, making it useful for treating allergies, motion sickness, and as a sedative before surgery. It comes in various forms, including tablets, syrup, and injections. On the other hand, prochlorperazine is a phenothiazine that primarily blocks dopamine and is available as a rectal suppository. It is not a first-choice medication due to its serious side effects, such as uncontrolled muscle movements and extreme sleepiness. Promethazine can be used in children over 2 years old, while prochlorperazine is not recommended for children under 2 years old or under 20 pounds. Additionally, promethazine is available as a lower-cost generic, whereas prochlorperazine is also available in a generic form but might be less convenient due to its rectal administration.

Promethazine

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Prochlorperazine

(Compro)

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Summary for Phenergan

Prescription only

Promethazine is a prescription medication with many uses, such as treatment or prevention of nausea, motion sickness, and allergy symptoms. Promethazine works by blocking several chemicals, including histamine, dopamine, and acetylcholine. It comes as tablets, an oral solution, rectal suppositories, and an injection. The dose of promethazine and how often you take it depends on your age and what medical condition you're taking it to treat. But it shouldn't be given to children younger than 2 years of age since it can cause serious breathing problems. Common side effects include sleepiness and dizziness.

Indications for Phenergan

Runny nose, watery eyes, and other symptoms of allergies
Runny or stuffy nose that isn't caused by allergies
Rash, swelling, anaphylaxis, and other symptoms of an allergic reaction
Dermographism
Treatment or prevention of nausea and vomiting before and after surgery
Treatment or prevention of motion sickness
Treatment of pain along with other pain medications after surgery
Help to relax your body and produce a light sleep, particularly before a procedure

Pros and Cons for Phenergan

Pros

Available as a lower-cost generic
Available in different formulations, such as a tablet, syrup, and injection
Starts working within 20 minutes

Cons

Can't be taken by children under 2 years old because risk of serious breathing problem
Higher risk of side effects in older adults
Can cause sleepiness

Common Side Effects for Phenergan

Feeling drowsy or tired
Dizziness
Confusion
Dry mouth
Nervousness
Blurry vision

The following side effects are those additionally reported with promethazine injection at the injection site:

Burning
Pain
Rash
Swelling

Warnings for Phenergan

Potentially life-threatening slow breathing (respiratory depression)
Serious tissue injury (Injection only)
Excessive sleepiness
Worsening of certain health problems
Seizures
Higher risk of infection (from low white blood cell count)
Risk of serious nerve problems (neuroleptic malignant syndrome)
Uncontrollable body movements

Summary for Compro

Prescription only

Prochlorperazine (Compro) rectal suppository is a typical antipsychotic. It's FDA-approved to treat severe nausea and vomiting in adults. But prochlorperazine (Compro) isn't a first-choice antiemetic because it can cause serious side effects, such as extreme sleepiness and uncontrolled muscle movements. While prochlorperazine (Compro) is a good option for people who can't take medications by mouth, some people might find it unpleasant or difficult to use because it needs to be inserted into the rectum, typically twice daily. Prochlorperazine (Compro) comes as a brand-name and generic medication.

Indications for Compro

Severe nausea and vomiting

Pros and Cons for Compro

Pros

Good option for people who have a hard time swallowing pills
Available as a generic medication
More convenient storage compared to some other suppositories because it doesn't need to be refrigerated

Cons

Might be hard for some people to insert the suppository
Not recommended for use in children
Might cause rare but permanent side effects, such as uncontrolled muscle movements

Common Side Effects for Compro

Drowsiness
Dizziness
Absent menstrual periods
Blurry vision
Low blood pressure

Warnings for Compro

Higher risk of death in older adults with dementia-related psychosis
Difficulty controlling muscle movements (tardive dyskinesia)
Other conditions with uncontrolled muscle movements (dystonia, Parkinsonian symptoms, and restlessness)
Neuroleptic malignant syndrome (NMS)
Cover up more serious health problems
Higher risk of infections
Higher risk of falls
Liver problems
Seizures
High prolactin levels
Difficulty maintaining normal body temperature