Compro Side Effects: What You Need to Know

Compro (Prochlorperazine) is a prescription medication used to treat severe nausea and vomiting. Like all medications, it comes with potential side effects — some mild and manageable, others that require immediate medical attention.

Understanding what to expect can help you feel more prepared and know when something is normal versus when it's time to call your doctor. This guide covers the full picture based on FDA labeling.

What Is Compro?

Compro is the brand name for Prochlorperazine in a 25 mg rectal suppository form. It belongs to the phenothiazine drug class and works by blocking dopamine receptors in the brain, particularly in the chemoreceptor trigger zone (CTZ), which controls nausea signals. Prochlorperazine is also available in oral tablets (5 mg and 10 mg) and as an injectable solution.

Common Side Effects

Most people who take Compro experience mild side effects, especially when first starting the medication. These usually improve as your body adjusts:

• Drowsiness and sedation — The most frequently reported side effect. Avoid driving or operating heavy machinery until you know how Compro affects you.
• Dizziness — Particularly when standing up quickly. Rise slowly from sitting or lying positions.
• Constipation — Drink plenty of water and eat fiber-rich foods to help manage this.
• Dry mouth — Sip water regularly, chew sugar-free gum, or use saliva substitutes.
• Blurred vision — Usually temporary. Avoid activities requiring sharp vision until it clears.
• Akathisia (restlessness) — An uncomfortable feeling of needing to move or inability to sit still. This is a movement-related side effect specific to dopamine-blocking medications.
• Mild tremor — Slight shaking, usually in the hands. Often mild and may improve over time.

If any of these side effects are bothersome or don't improve within a few days, talk to your doctor. They may adjust your dose or suggest ways to manage them.

Serious Side Effects

While less common, Compro can cause serious side effects that need prompt medical attention. Contact your doctor immediately or go to the emergency room if you experience any of the following:

• Tardive dyskinesia — Involuntary, repetitive movements of the face, tongue, or limbs (lip smacking, tongue darting, grimacing). This condition can become permanent even after stopping the medication. Risk increases with longer use and higher doses.
• Neuroleptic malignant syndrome (NMS) — A rare but potentially fatal reaction. Symptoms include very high fever, severe muscle rigidity, altered mental status, rapid heartbeat, and unstable blood pressure. This is a medical emergency.
• Acute dystonia — Sudden, painful muscle spasms or contractions, often in the neck, jaw, or eyes. More common in younger patients and with higher doses.
• Orthostatic hypotension — A significant drop in blood pressure when standing, causing lightheadedness, fainting, or falls.
• Prolonged QTc interval — Changes in heart rhythm that can lead to dangerous cardiac events. Tell your doctor if you have a history of heart problems.
• Agranulocytosis and leukopenia — A dangerous drop in white blood cells that increases infection risk. Watch for unexplained fever, sore throat, or signs of infection.
• Seizures — Prochlorperazine lowers the seizure threshold. Higher risk in patients with a history of epilepsy or seizure disorders.
• Falls and fractures — Particularly in elderly patients, due to sedation, dizziness, and orthostatic hypotension.

Boxed Warning

Compro carries an FDA boxed warning (the most serious type of warning): elderly patients with dementia-related psychosis who are treated with antipsychotic drugs like Prochlorperazine have an increased risk of death. Compro is not approved for treating dementia-related psychosis.

Who's at Higher Risk for Side Effects?

Certain groups may be more vulnerable to Compro's side effects:

• Elderly patients — Higher risk of falls, tardive dyskinesia, sedation, and the serious effects noted in the boxed warning.
• Children under 2 years or under 20 lbs — Compro is contraindicated in this group.
• Pregnant women — Not recommended unless benefits clearly outweigh risks. Discuss with your OB-GYN.
• Nursing mothers — Prochlorperazine is excreted in breast milk. Use with caution.
• Patients with liver disease — The drug is metabolized by the liver, so impaired liver function can increase side effects.
• People with cardiovascular disease — Due to risk of orthostatic hypotension and QTc prolongation.
• Patients with seizure disorders — Prochlorperazine lowers the seizure threshold.

How to Manage Side Effects

Here are practical tips for dealing with the most common Compro side effects:

• For drowsiness: Take Compro at bedtime if your dosing schedule allows. Avoid alcohol and other sedating medications, which can make drowsiness worse.
• For dizziness: Stand up slowly. Sit on the edge of the bed for a minute before getting up. Stay hydrated.
• For constipation: Increase fiber intake, drink more water, and stay physically active. Ask your doctor about a stool softener if needed.
• For dry mouth: Sip water throughout the day, use sugar-free candy or gum, and avoid caffeine and alcohol which can worsen dryness.
• For restlessness (akathisia): Tell your doctor — they may lower the dose or add a medication like a beta-blocker to help.

Never stop taking Compro suddenly without talking to your doctor, as this could cause withdrawal effects or a return of your symptoms.

When to Call Your Doctor

Call your doctor if you experience:

• Side effects that don't improve or get worse over time
• Any involuntary movements (face, tongue, limbs)
• Unexplained fever, muscle rigidity, or confusion
• Fainting or severe dizziness
• Signs of infection (fever, sore throat, mouth sores)
• Chest pain, irregular heartbeat, or palpitations
• Seizures

Go to the emergency room immediately if you suspect neuroleptic malignant syndrome (high fever + muscle rigidity + confusion) or experience a seizure.

Final Thoughts

Most people tolerate Compro well, especially at lower doses and for short-term use. The common side effects — drowsiness, dizziness, dry mouth — are manageable for most patients. But it's important to be aware of the serious side effects, particularly tardive dyskinesia and NMS, and to report any unusual symptoms to your doctor right away.

For more information about how Compro works, read our complete guide to Compro. If you're concerned about drug interactions, we have a dedicated guide for that too.