cimetidine vs risperidone
Side-by-side comparison of cimetidine and risperidone. Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.
major Known Drug Interaction
Dose adjustment is not recommended for risperidone tablets when co-administered with ranitidine, cimetidine, amitriptyline, or erythromycin [see Table 18 ] . Do not exceed twice the patient’s usual dose Enzyme (CYP3A) inhibitors Ranitidine 150 mg twice daily 1 mg single dose 1.2 1.4 Dose adjustment not needed Cimetidine 400 mg twice daily 1 mg single dose 1.1 1.3 Dose adjustment not needed Erythromycin 500 mg four times daily 1 mg single dose 1.1 0.94 Dose adjustment not needed Other Drugs Amitriptyline 50 mg twice daily 3 mg twice daily 1.2 1.1 Dose adjustment not Needed *Change relative...
Recommendation: No dose changes are needed when taking these two medicines together.
Tagamet
Risperdal
Cimetidine (Tagamet) reduces stomach acid. It is used to treat ulcers, heartburn, and other conditions where too much acid is produced.
Risperidone is a medicine used to treat certain mental disorders. It can help reduce symptoms like hallucinations, delusions, and aggression.
Cimetidine treats active duodenal ulcers for short periods. It can also be used long-term at a lower dose to prevent ulcers from returning. This medicine also treats active benign gastric ulcers for a short time. Additionally, it can help with erosive gastroesophageal reflux disease (GERD), which damages the esophagus.
Risperidone is used to treat schizophrenia in adults and teens. It also treats manic or mixed episodes of bipolar I disorder, either alone or with lithium or valproate. Additionally, it can help with irritability, including aggression and self-injury, in children and teens with autism.
Cimetidine is an H2 receptor antagonist. This means it blocks histamine from attaching to certain cells in your stomach. By blocking histamine, cimetidine reduces the amount of acid your stomach makes.
Risperidone works by changing the levels of certain natural substances in the brain. These substances are called neurotransmitters. By balancing these chemicals, risperidone can reduce symptoms of mental disorders.
- • Headache
- • Dizziness
- • Diarrhea
- • Parkinsonism (slowed movement, stiffness)
- • Restlessness
- • Muscle stiffness or spasms
- • Tremors
- • Sleepiness
- Long-term kidney disease 1,264
- Sudden kidney damage 710
- Kidney failure 694
- Feeling sick to your stomach 681
- Feeling tired 599
- Breast enlargement in males 24,608
- Unusual weight gain 9,446
- Weight gain 9,089
- Mental or emotional problem 5,947
- Harm or damage to the body 4,624
Reversible confusional states (like mental confusion, agitation, or hallucinations) have been reported, mostly in severely ill patients. These usually appear within 2-3 days of starting treatment and clear up within 3-4 days of stopping the drug.
Risperidone may increase the risk of death in elderly patients who have dementia-related psychosis. Risperidone is not approved for treating dementia-related psychosis.
Tell your doctor if you are pregnant or plan to become pregnant. The effects of cimetidine during pregnancy are not fully known. Talk to your doctor about the risks and benefits of taking cimetidine while breastfeeding.
Tell your doctor if you are pregnant or plan to become pregnant. Babies born to mothers who take risperidone in the last 3 months of pregnancy may have withdrawal symptoms or other problems after birth. There is a pregnancy registry to monitor outcomes in women exposed to risperidone during pregnancy. You can contact the registry at 1-866-961-2388.
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How to Read This cimetidine vs risperidone Comparison
cimetidine is classified in the H2 Receptor Antagonist drug class, while risperidone sits within the Atypical Antipsychotic class. Drugs from different classes work through distinct mechanisms, so a head-to-head comparison illustrates trade-offs rather than equivalence. Both drugs are split between OTC and prescription status, which affects access and supervision.
Adverse event totals above are pulled from the FDA's Adverse Event Reporting System (FAERS). For these top-ranked reactions alone, cimetidine has 3,948 submissions while risperidone has 53,714. Those figures reflect cumulative reporting volume, not per-patient risk, so older, widely dispensed drugs typically look worse on count alone. These two drugs have a known major interaction flagged in FDA labeling, attributed to cimetidine can slightly slow down the enzymes that break down risperidone, but the effect is very small.. Serious warnings, pregnancy guidance, and contraindications can differ even when indications overlap.
A table cannot substitute for clinical judgment. Effectiveness, tolerability, drug-drug interactions with your other medications, kidney and liver function, pregnancy status, insurance formulary, and price all feed into a decision that only a licensed prescriber can make responsibly. Data here is sourced from FDA Structured Product Labels (SPL) and FAERS, both of which update as manufacturers and clinicians submit new information. This page is for educational purposes only, is not medical advice, and should not be used to self-switch between cimetidine and risperidone - always consult your physician or pharmacist first.
Important: This comparison is for informational purposes only. Drug effects vary between individuals. Always consult your doctor or pharmacist for personalized medical advice.