cimetidine vs desloratadine

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Side-by-side comparison of cimetidine and desloratadine. Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.

minor Known Drug Interaction

[ See Clinical Pharmacology (12.3) .] 7.3 Cimetidine In controlled clinical studies co-administration of desloratadine with cimetidine, a histamine H 2 -receptor antagonist, resulted in increased plasma concentrations of desloratadine and 3 hydroxydesloratadine, but there were no clinically relevant changes in the safety profile of desloratadine.

Drug Class
cimetidine H2 Receptor Antagonist
desloratadine Second-Generation Antihistamine
Type
cimetidine Over-the-Counter
desloratadine Prescription
Summary
cimetidine

Cimetidine (Tagamet) reduces stomach acid. It is used to treat ulcers, heartburn, and other conditions where too much acid is produced.

desloratadine

Desloratadine is an antihistamine medicine. It helps relieve allergy symptoms.

What It Treats
cimetidine

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.

desloratadine

This medicine treats allergy symptoms. It can help with seasonal allergies like hay fever. It also treats year-round allergies and chronic hives by reducing itching and the number and size of hives.

How It Works
cimetidine

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.

desloratadine

Desloratadine blocks histamine in your body. Histamine is a substance that causes allergy symptoms. By blocking histamine, this medicine reduces those symptoms.

Common Side Effects
cimetidine
  • Headache
  • Dizziness
  • Diarrhea
desloratadine
  • Sore throat
  • Dry mouth
  • Muscle pain
  • Tiredness
  • Sleepiness
FAERS Reports
cimetidine
  • Chronic Kidney Disease 1,264
  • Acute Kidney Injury 710
  • Renal Failure 694
  • Nausea 681
  • Fatigue 598
desloratadine
  • Fatigue 601
  • Nausea 582
  • Dyspnoea 532
  • Headache 465
  • Diarrhoea 448
Serious Warnings
cimetidine

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.

desloratadine

Stop taking this medicine and get medical help right away if you have an allergic reaction. Signs of a reaction include rash, itching, hives, swelling, trouble breathing, or anaphylaxis.

Pregnancy
cimetidine

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.

desloratadine

Not enough studies have been done to know if desloratadine is safe during pregnancy. Talk to your doctor if you are pregnant or plan to become pregnant. It is not known if desloratadine passes into breast milk.

Also Compare, Nearby Drugs

How to Read This cimetidine vs desloratadine Comparison

cimetidine is classified in the H2 Receptor Antagonist drug class, while desloratadine sits within the Second-Generation Antihistamine 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 3,947 submissions while desloratadine has 2,628. 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 minor interaction flagged in FDA labeling, attributed to cimetidine slows down the liver's ability to process desloratadine, which leads to higher levels of the medicine in your blood.. Serious warnings, pregnancy guidance, and contraindications can differ even when indications overlap.

A table cannot represent individual circumstances. Data here is sourced from FDA Structured Product Labels (SPL) and FAERS, both of which update as manufacturers and clinicians submit new information. This registry does not provide medical, treatment, substitution, or medication-change directions for cimetidine or desloratadine.

Registry boundary: This comparison displays source-record fields and does not provide individualized medical direction.