cimetidine vs doxepin
According to this portal's Publishing Organization, this page was last reviewed in August 2026 against our methodology. Figures and extracts on this site, including tables above 1,000 rows when the corpus is that large, are the publisher's responsibility.
Side-by-side comparison of cimetidine and doxepin. 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
( 4.2 ) Cimetidine: Increases exposure to doxepin. 7.2 Cimetidine Doxepin exposure is doubled with concomitant administration of cimetidine, a nonspecific inhibitor of CYP isozymes. A maximum dose of 3 mg is recommended in adults and elderly when cimetidine is co-administered with doxepin [see Clinical Pharmacology (12.3 )] 7.3 Alcohol When taken with doxepin, the sedative effects of alcohol may be potentiated [ see Warnings and Precautions (5.2 , 5.4 )].
Tagamet
Sinequan, Silenor
Cimetidine (Tagamet) reduces stomach acid. It is used to treat ulcers, heartburn, and other conditions where too much acid is produced.
Doxepin is a medicine that can help you stay asleep. It belongs to a class of drugs called tricyclic antidepressants.
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.
Doxepin is used to treat insomnia, which means you have trouble staying asleep. It can help you sleep better if you have problems with waking up during the night. This medicine has been tested for up to 3 months.
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.
Doxepin works by affecting certain natural chemicals in the brain that help regulate sleep. It helps to keep you asleep throughout the night. It is a low dose formulation of a tricyclic antidepressant.
- • Headache
- • Dizziness
- • Diarrhea
- • Feeling sleepy or drowsy
- • Feeling sick to your stomach
- • Upper respiratory tract infection (like a cold)
- Chronic Kidney Disease 1,264
- Acute Kidney Injury 710
- Renal Failure 694
- Nausea 681
- Fatigue 598
- Toxicity To Various Agents 801
- Completed Suicide 613
- Fatigue 599
- Nausea 557
- Pain 527
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.
After taking doxepin, some people have done things like driving a car while not fully awake. You might not remember doing it. This can be dangerous, so tell your doctor right away if this happens. Doxepin may also worsen depression or cause suicidal thoughts. Tell your doctor if you notice any new or worsening symptoms of depression.
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.
Taking doxepin late in pregnancy may cause problems for the newborn baby, like trouble breathing or feeding. Breastfeeding is not recommended while taking this medicine.
Also Compare, Nearby Drugs
Compare cimetidine with
Compare doxepin with
How to Read This cimetidine vs doxepin Comparison
cimetidine is classified in the H2 Receptor Antagonist drug class, while doxepin sits within the Tricyclic Antidepressant (TCA) 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 doxepin has 3,097. 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 blocks the enzymes that normally break down doxepin, which causes the amount of doxepin in your body to double.. 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 doxepin.
Registry boundary: This comparison displays source-record fields and does not provide individualized medical direction.