DIMENHYDRINATE: 1,934 Adverse Event Reports & Safety Profile
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Drug Class: Histamine H1 Receptor Antagonists [MoA] · Route: ORAL · Manufacturer: Major Pharmaceuticals · FDA Application: 040519 · HUMAN OTC DRUG · FDA Label: Available
First Report: 19970630 · Latest Report: 20250301
What Are the Most Common DIMENHYDRINATE Side Effects?
All DIMENHYDRINATE Side Effects by Frequency
| Side Effect | Reports | % of Total | Deaths | Hosp. |
|---|---|---|---|---|
| Fatigue | 542 | 28.0% | 3 | 209 |
| Nausea | 522 | 27.0% | 10 | 304 |
| Vomiting | 436 | 22.5% | 10 | 190 |
| Malaise | 426 | 22.0% | 2 | 156 |
| Anxiety | 371 | 19.2% | 1 | 176 |
| Dizziness | 358 | 18.5% | 2 | 28 |
| Headache | 311 | 16.1% | 3 | 212 |
| Cystitis | 302 | 15.6% | 0 | 126 |
| Chest discomfort | 299 | 15.5% | 0 | 192 |
| Pyrexia | 295 | 15.3% | 6 | 201 |
| Fall | 284 | 14.7% | 1 | 167 |
| Drug ineffective | 278 | 14.4% | 3 | 158 |
| Pneumonia | 273 | 14.1% | 1 | 140 |
| Diarrhoea | 270 | 14.0% | 2 | 79 |
| Abdominal pain | 264 | 13.7% | 2 | 66 |
| Rash | 248 | 12.8% | 12 | 68 |
| Cough | 246 | 12.7% | 0 | 147 |
| Nasopharyngitis | 246 | 12.7% | 1 | 134 |
| Angina pectoris | 240 | 12.4% | 1 | 170 |
| Depression | 230 | 11.9% | 0 | 52 |
Who Reports DIMENHYDRINATE Side Effects? Age & Gender Data
Gender: 73.8% female, 26.2% male. Average age: 45.4 years. Most reports from: CA. View detailed demographics →
Is DIMENHYDRINATE Getting Safer? Reports by Year
| Year | Reports | Deaths | Hosp. |
|---|---|---|---|
| 2001 | 9 | 9 | 9 |
| 2003 | 2 | 0 | 2 |
| 2008 | 1 | 0 | 1 |
| 2009 | 2 | 0 | 2 |
| 2010 | 1 | 1 | 1 |
| 2011 | 1 | 1 | 1 |
| 2012 | 5 | 0 | 4 |
| 2013 | 6 | 0 | 4 |
| 2014 | 9 | 0 | 7 |
| 2015 | 20 | 2 | 6 |
| 2016 | 14 | 0 | 5 |
| 2017 | 43 | 7 | 25 |
| 2018 | 33 | 1 | 18 |
| 2019 | 25 | 1 | 13 |
| 2020 | 8 | 1 | 3 |
| 2021 | 16 | 0 | 3 |
| 2022 | 42 | 2 | 13 |
| 2023 | 22 | 1 | 3 |
| 2024 | 10 | 1 | 4 |
| 2025 | 3 | 0 | 0 |
What Is DIMENHYDRINATE Used For?
| Indication | Reports |
|---|---|
| Product used for unknown indication | 728 |
| Premedication | 291 |
| Nausea | 215 |
| Anxiety | 174 |
| Constipation | 110 |
| Vomiting | 101 |
| Morning sickness | 66 |
| Migraine | 47 |
| Hyperemesis gravidarum | 41 |
| Pruritus | 33 |
DIMENHYDRINATE vs Alternatives: Which Is Safer?
Other Drugs in Same Class: Histamine H1 Receptor Antagonists [MoA]
Official FDA Label for DIMENHYDRINATE
Official prescribing information from the FDA-approved drug label.
Drug Description
DESCRIPTION Dimenhydrinate, an anti-nauseant/antiemetic, is the 8-chlorotheophylline salt of diphenhydramine. It contains not less than 53% and not more than 55.5% of diphenhydramine, and not less than 44% and not more than 47% of 8-chlorotheophylline, calculated on the dried basis. Chemically, it is 8-chlorotheophylline compound with 2(diphenylmethoxy)-N,N-dimethylethylamine (1:1), and the structural formula is: C 17 H 21 NO•C 7 H 7 ClN 4 O 2 M.W.
469.96 Dimenhydrinate Injection, USP contains a sterile solution of Dimenhydrinate 50 mg/mL; Propylene Glycol 50%; Benzyl Alcohol 5% as preservative; and Water for Injection q.s.
Sodium
Hydroxide and/or Hydrochloric Acid may have been used to adjust pH. structure
FDA Approved Uses (Indications)
INDICATIONS AND USAGE Dimenhydrinate Injection, USP is indicated for the prevention and treatment of nausea, vomiting, or vertigo of motion sickness.
Dosage & Administration
DOSAGE AND ADMINISTRATION Dimenhydrinate in the injectable form is indicated when the oral form is impractical.
Adults
Nausea or vomiting may be expected to be controlled for approximately 4 hours with 50 mg, and prevented by a similar dose every 4 hours. Its administration may be attended by some degree of drowsiness in some patients, and 100 mg every 4 hours may be given in conditions in which drowsiness is not objectionable or is even desirable. For intramuscular administration, each milliliter (50 mg) of solution is injected as needed, but for intravenous administration, each milliliter (50 mg) of solution must be diluted in 10 mL of 0.9% Sodium Chloride Injection, USP and injected over a period of 2 minutes.
Pediatric
For intramuscular administration, 1.25 mg/kg of body weight or 37.5 mg/m 2 of body surface area is administered four times daily. The maximum dose should not exceed 300 mg daily (see CONTRAINDICATIONS ). Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit.
Adults
Nausea or vomiting may be expected to be controlled for approximately 4 hours with 50 mg, and prevented by a similar dose every 4 hours. Its administration may be attended by some degree of drowsiness in some patients, and 100 mg every 4 hours may be given in conditions in which drowsiness is not objectionable or is even desirable. For intramuscular administration, each milliliter (50 mg) of solution is injected as needed, but for intravenous administration, each milliliter (50 mg) of solution must be diluted in 10 mL of 0.9% Sodium Chloride Injection, USP and injected over a period of 2 minutes.
Pediatric
For intramuscular administration, 1.25 mg/kg of body weight or 37.5 mg/m 2 of body surface area is administered four times daily. The maximum dose should not exceed 300 mg daily (see CONTRAINDICATIONS ). Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit.
Contraindications
CONTRAINDICATIONS Neonates and patients with a history of hypersensitivity to dimenhydrinate or its components (diphenhydramine or 8-chlorotheophylline) should not be treated with dimenhydrinate. Note: This product contains Benzyl Alcohol.
Benzyl
Alcohol has been associated with a fatal “Gasping Syndrome” in premature infants and infants of low birth weight.
Known Adverse Reactions
ADVERSE REACTIONS To report SUSPECTED ADVERSE REACTIONS, contact Fresenius Kabi USA, LLC at 1-800-551-7176 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. The most frequent adverse reaction to dimenhydrinate is drowsiness. Dizziness may also occur. Symptoms of dry mouth, nose and throat, blurred vision, difficult or painful urination, headache, anorexia, nervousness, restlessness or insomnia (especially in pediatric patients), skin rash, thickening of bronchial secretions, tachycardia, epigastric distress, lassitude, excitation, and nausea have been reported.
Warnings
WARNINGS Caution should be used when dimenhydrinate is given in conjunction with certain antibiotics that may cause ototoxicity, since dimenhydrinate is capable of masking ototoxic symptoms, and an irreversible state may be reached. This drug may impair the mental and/or physical abilities required for the performance of potentially hazardous tasks, such as driving a vehicle or operating machinery. The concomitant use of alcohol or other central nervous system depressants may have an additive effect. Therefore, patients should be warned accordingly. Dimenhydrinate should be used with caution in patients having conditions which might be aggravated by anticholinergic therapy (i.e., prostatic hypertrophy, stenosing peptic ulcer, pyloroduodenal obstruction, bladder neck obstruction, narrow-angle glaucoma, bronchial asthma, or cardiac arrhythmias). The preparation should not be injected intra-arterially.
Pediatric Patients
For infants and children especially, antihistamines in overdosage may cause hallucinations, convulsions, or death. As in adults, antihistamines may diminish mental alertness in pediatric patients. In the young child, particularly, they may produce excitation (see CONTRAINDICATIONS ).
Pediatric Patients
For infants and children especially, antihistamines in overdosage may cause hallucinations, convulsions, or death. As in adults, antihistamines may diminish mental alertness in pediatric patients. In the young child, particularly, they may produce excitation (see CONTRAINDICATIONS ).
Precautions
PRECAUTIONS General Drowsiness may be experienced by some patients, especially with high dosage. This effect frequently is not undesirable in conditions for which the drug is used. Information for Patients Because of the potential for drowsiness, patients taking dimenhydrinate should be cautioned against operating automobiles or dangerous machinery (see WARNINGS ). Carcinogenesis, Mutagenesis, Impairment of Fertility Mutagenicity screening tests performed with dimenhydrinate, diphenhydramine, and 8-chlorotheophylline produced positive results in the bacterial systems and negative results in the mammalian systems. There are no human data that indicate dimenhydrinate is a carcinogen or mutagen or that it impairs fertility.
Pregnancy Pregnancy
Category B. Reproduction studies have been performed in rats at doses up to 20 times the human dose, and in rabbits at doses up to 25 times the human dose (on a mg/kg basis), and have revealed no evidence of impaired fertility or harm to the fetus due to dimenhydrinate. There are no adequate and well-controlled studies in pregnant women. However, clinical studies in pregnant women have not indicated that dimenhydrinate increases the risk of abnormalities when administered in any trimester of pregnancy. It would appear that the possibility of fetal harm is remote when the drug is used during pregnancy. Nevertheless, because the studies in humans cannot rule out the possibility of harm, dimenhydrinate should be used during pregnancy only if clearly needed. Labor and Delivery The safety of dimenhydrinate given during labor and delivery has not been established. Reports have indicated dimenhydrinate may have an oxytocic effect. Caution is advised when this effect is unwanted or in situations where it may prove detrimental.
Nursing Mothers
Small amounts of dimenhydrinate are excreted in breast milk. Because of the potential for adverse reactions in nursing infants from dimenhydrinate, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.
General
Drowsiness may be experienced by some patients, especially with high dosage. This effect frequently is not undesirable in conditions for which the drug is used.
Information for Patients Because of the potential for drowsiness, patients taking dimenhydrinate should be cautioned against operating automobiles or dangerous machinery (see WARNINGS ).
Carcinogenesis, Mutagenesis, Impairment of Fertility Mutagenicity screening tests performed with dimenhydrinate, diphenhydramine, and 8-chlorotheophylline produced positive results in the bacterial systems and negative results in the mammalian systems. There are no human data that indicate dimenhydrinate is a carcinogen or mutagen or that it impairs fertility.
Labor and Delivery The safety of dimenhydrinate given during labor and delivery has not been established. Reports have indicated dimenhydrinate may have an oxytocic effect. Caution is advised when this effect is unwanted or in situations where it may prove detrimental.
Nursing Mothers
Small amounts of dimenhydrinate are excreted in breast milk. Because of the potential for adverse reactions in nursing infants from dimenhydrinate, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.
Active Ingredient
Drug Facts Active ingredient (in each tablet)
Dimenhydrinate
50 mg
Inactive Ingredients
Inactive ingredients Corn starch, croscarmellose sodium, FD&C yellow 6 aluminum lake, iron oxide yellow, lactose monohydrate, magnesium stearate, microcrystalline cellulose, polyethylene glycol, polyvinyl alcohol, silicon dioxide, talc, titanium dioxide