cimetidine vs levofloxacin
Side-by-side comparison of cimetidine and levofloxacin. 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
7.8 Probenecid and Cimetidine No significant effect of probenecid or cimetidine on the Cmax of levofloxacin was observed in a clinical study involving healthy volunteers. The AUC and t 1/2 of levofloxacin were higher while CL/F and CLR were lower during concomitant treatment of levofloxacin with probenecid or cimetidine compared to levofloxacin alone. However, these changes do not warrant dosage adjustment for levofloxacin when probenecid or cimetidine is co-administered.
Recommendation: No dosage changes are needed, so you can safely take these medications together as prescribed.
Tagamet
Levaquin
Cimetidine (Tagamet) reduces stomach acid. It is used to treat ulcers, heartburn, and other conditions where too much acid is produced.
Levofloxacin is an antibiotic that fights bacteria in your body. It is used to treat different types of infections.
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.
Levofloxacin treats infections like pneumonia, skin infections, prostate infections, and urinary tract infections. It can also treat anthrax after exposure and plague. This medicine should only be used for certain infections when other options won't work.
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.
Levofloxacin belongs to a class of drugs called fluoroquinolones. It works by stopping bacteria from multiplying. This helps your body fight off the infection.
- • Headache
- • Dizziness
- • Diarrhea
- • Nausea
- • Headache
- • Diarrhea
- • Trouble sleeping
- • Constipation
- Long-term kidney disease 1,264
- Sudden kidney damage 710
- Kidney failure 694
- Feeling sick to your stomach 681
- Feeling tired 599
- Dyspnoea 2,949
- Pneumonia 2,862
- Nausea 2,791
- Pyrexia 2,725
- Fatigue 2,658
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.
This drug has serious warnings. Levofloxacin can cause tendon problems, nerve damage, and central nervous system effects. It can also make muscle weakness worse if you have myasthenia gravis. If you have any of these side effects, stop taking the medicine and call your doctor right away. Only use this medicine if you have no other treatment options for uncomplicated urinary tract infections, bronchitis, or sinusitis.
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. Levofloxacin should only be used during pregnancy if the benefit outweighs the risk to the baby. It may pass into breast milk, so talk to your doctor about breastfeeding.
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How to Read This cimetidine vs levofloxacin Comparison
cimetidine is classified in the H2 Receptor Antagonist drug class, while levofloxacin sits within the Fluoroquinolone Antibiotic 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 levofloxacin has 13,985. 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 makes it harder for the kidneys to clear levofloxacin, causing the antibiotic to stay in the body slightly longer.. 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 levofloxacin - 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.