cimetidine vs posaconazole
Side-by-side comparison of cimetidine and posaconazole. 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
Interaction Drug Interaction Rifabutin, phenytoin, efavirenz, cimetidine, esomeprazole* Avoid coadministration unless the benefit outweighs the risks ( 7.6 , 7.7 , 7.8 , 7.9 ) Other drugs metabolized by CYP3A4 Consider dosage adjustment and monitor for adverse effects and toxicity ( 7.1 , 7.10 , 7.11 ) Digoxin Monitor digoxin plasma concentrations ( 7.12 ) Fosamprenavir, metoclopramide* Monitor for breakthrough fungal infections ( 7.6 , 7.13 ) *The drug interactions with esomeprazole and metoclopramide do not apply to posaconazole tablets.
Recommendation: Avoid taking these two medicines together unless your doctor determines that the benefits are greater than the risks.
Tagamet
Noxafil
Cimetidine (Tagamet) reduces stomach acid. It is used to treat ulcers, heartburn, and other conditions where too much acid is produced.
Posaconazole is an antifungal medicine. It helps prevent certain fungal infections in people with weakened immune systems.
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.
Posaconazole prevents Aspergillus and Candida infections. You may need this medicine if you have a high risk of getting these infections. This often includes people who had a stem cell transplant or have certain blood cancers and are on chemotherapy.
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.
Posaconazole belongs to a class of drugs called azole antifungals. It works by stopping the growth of fungi. This helps your body fight off the infection.
- • Headache
- • Dizziness
- • Diarrhea
- • Diarrhea
- • Nausea
- • Fever
- • Vomiting
- • Headache
- Long-term kidney disease 1,264
- Sudden kidney damage 710
- Kidney failure 694
- Feeling sick to your stomach 681
- Feeling tired 599
- Fever with low white blood cell count 1,018
- The medicine is interacting with another medicine 930
- Death 928
- Fever 850
- Low white blood cell count 705
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.
Posaconazole can interact with many other medicines. It can cause heart rhythm problems (QT prolongation). It can also cause liver problems. Tell your doctor about all the medicines you take.
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.
Posaconazole may harm an unborn baby. Talk to your doctor if you are pregnant or plan to become pregnant. It is not known if posaconazole passes into breast milk, so talk to your doctor if you are breastfeeding.
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How to Read This cimetidine vs posaconazole Comparison
cimetidine is classified in the H2 Receptor Antagonist drug class, while posaconazole sits within the Azole Antifungal 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 posaconazole has 4,431. 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 changes the environment in the stomach, which can prevent the body from absorbing enough posaconazole into the bloodstream.. 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 posaconazole - 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.