Dimenhydrinate 50mg tablets
Requires a prescription from a doctor or prescriber
Anti-emetic and antihistamine medication
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Yellow Card reports
The MHRA Yellow Card scheme collects reports of suspected side effects from healthcare professionals and patients. View the Drug Analysis Profile (iDAP) for real-world adverse reaction data.
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Suspected adverse reactions reported for Dimenhydrinate
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Data from the MHRA Yellow Card scheme. A reported reaction does not necessarily mean the medicine caused it. Contains public sector information licensed under the Open Government Licence v3.0.
EudraVigilance
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Suspected adverse reactions reported for Dimenhydrinate
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1 branded products available
WHO defined daily dose (DDD)
300 mg
Not a recommended dose. The DDD is the assumed average maintenance dose per day for a drug used for its main indication in adults. It is a statistical measure used for research and comparison purposes only.
Source: WHO Collaborating Centre for Drug Statistics Methodology, distributed via the NHS dm+d supplementary BNF/ATC mapping files (NHSBSA). Contains public sector information licensed under the Open Government Licence v3.0.
Therapeutically similar medicines
Similarity is based on WHO Anatomical Therapeutic Chemical (ATC) classification and on a factual NHS dm+d therapeutic-grouping code prefix. Source data: NHS dm+d via TRUD (OGL v3.0), WHO ATC/DDD Index.
NHS prescribing volume and spending trends
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Codes for healthcare professionals and prescribing systems
These codes are used by healthcare IT systems and prescribers to identify this medicine.
NHS UK identifiers
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SNOMED CT and dm+d codes from NHS TRUD (Technology Reference data Update Distribution), licensed under the Open Government Licence v3.0. BNF code shown is the factual mapping value distributed by NHS Business Services Authority (NHSBSA) in the dm+d supplementary file under OGL v3.0; it is not affiliated with, nor licensed from, the publishers of the British National Formulary. ATC codes from the WHO Collaborating Centre for Drug Statistics Methodology (whocc.no).
Active and completed clinical studies from ClinicalTrials.gov
Source: ClinicalTrials.gov, a database of the U.S. National Library of Medicine (NLM), National Institutes of Health (NIH). Data accessed via ClinicalTrials.gov API v2. Trial information is provided for research purposes and does not constitute medical advice.
Academic studies and reviews for this medicine's active substance
Showing the 50 most relevant studies.
Reviews & meta-analyses: 11 · Randomised trials: 10 · 1989–2026
Showing the 50 most relevant studies, sorted by most relevant.
Peter Kranke, Adam Morin, Norbert Roewer, et al.
Acta Anaesthesiologica Scandinavica, 2002
- Antiemetics
- Dimenhydrinate
- Postoperative Nausea and Vomiting
Mosca A, Chiappini S, Mancusi G, et al.
2025
- Psychoses, Substance-Induced
- Histamine Antagonists
- Antitussive Agents
BackgroundThe widespread availability and accessibility of over-the-counter (OTC) medicines play a vital role in modern healthcare systems, enabling individuals to manage minor health concerns independently. However, certain OTC medications possess pharmacological properties that render them susceptible to misuse and abuse, including stimulants, laxatives, sedatives, and opiate-containing products. Misuse involves improper dosage, duration, or indication, while abuse entails non-therapeutic use to achieve psychoactive effects or other illicit purposes, potentially leading to dependence and addiction. This review explores the risk of developing psychotic symptoms associated with OTC drug misuse. Synthesizing existing literature, it comprehensively examines the relationship between antihistamines, cough medicines, and decongestants misuse, and the onset of psychotic symptoms.MethodsA systematic literature review was carried out using Pubmed, Scopus and Web of Science databases through the following search strategy: ("diphenhydramine" OR "promethazine" OR "chlorpheniramine" OR "dimenhydrinate" OR "dextromethorphan" OR "pseudoephedrine" OR codeine- based cough medicines) AND ("abuse" OR "misuse" OR "craving" OR "addiction") NOT review NOT (animal OR rat OR mouse). For data gathering purposes, the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) was followed. Research methods were registered on PROSPERO (CRD42024527558).ResultsWe analysed 46 relevant studies out of an initial pool of 2,677 articles. Key findings indicate that antihistamines, dextromethorphan, and other OTC drugs can induce psychotic symptoms, such as paranoia, hallucinations, and thought disorders when abused. Dextromethorphan is particularly associated with a chronic tendency towards psychosis, whereas other substances more commonly result in acute substance-induced psychosis.ConclusionThe study underscores the necessity for increased awareness and specific interventions to address the misuse of OTC drugs and their potential to cause significant psychiatric disorders, emphasizing the broader public health implications of such misuse.
Abstract licence: CC BY
Martín-Enguix D, Gómez Gabaldón N, Amaro-Gahete FJ
2025
- Vertigo
- Dimenhydrinate
- Cinnarizine
Vertigo is a frequent reason for medical consultation and may result from a wide range of aetiologies. Betahistine and the fixed low-dose combination of cinnarizine 20 mg and dimenhydrinate 40 mg are commonly used therapeutic options, each with distinct antivertigo profiles. This systematic review, conducted in accordance with the PRISMA guidelines, aims to compare the efficacy and safety of these two treatments in patients with vertigo of various origins. A comprehensive search was conducted in PubMed, Cochrane Library, Google Scholar, and ClinicalTrials.gov, with no restrictions on language or publication date. Eligible studies included clinical trials and meta-analyses comparing the fixed low-dose combination (20 mg/40 mg) versus betahistine (12 or 16 mg), assessing efficacy through the Mean Vertigo Score (MVS) and safety based on the incidence of adverse events (AEs). The RoB 2 and ROBIS tools were used to evaluate the risk of bias. A total of nine studies were identified (six clinical trials and three meta-analyses). In five of the six clinical trials, the fixed low-dose combination significantly reduced MVS compared with betahistine at weeks 1 and/or 4 (p < .05); these findings were corroborated by the three meta-analyses. Regarding safety, both treatments were well tolerated, with no serious AEs reported and a generally lower incidence observed in the fixed low-dose combination group. Overall, the fixed low-dose combination demonstrated superior clinical efficacy from the first week of treatment, along with a more favourable tolerability and safety profile. These results support its preferential use in the management of acute vestibular syndrome.
Abstract licence: CC BY
Frivaldszky L, Obeidat M, Hegyi P, et al.
2026
- Pregnancy Complications
- Morning Sickness
- Nausea
Background: Nausea and vomiting in pregnancy affects up to 80% of pregnant women and may progress to hyperemesis gravidarum, leading to maternal morbidity and adverse pregnancy outcomes. Despite numerous pharmacological and non-pharmacological options, the comparative efficacy and safety of these interventions remain unclear. Methods: We conducted a systematic review and network meta-analysis of randomized controlled trials assessing pharmacological and non-pharmacological interventions for nausea and vomiting in pregnancy. The databases searched included CENTRAL, PubMed, and EMBASE (up to 28 May 2024). Eligible trials compared interventions with a placebo in pregnant women with nausea and vomiting in pregnancy. The primary outcomes were symptom severity, assessed using validated tools. Safety outcomes included adverse effects. Data were pooled using frequentist pairwise and network meta-analyses. The risk of bias was assessed using the RoB2 tool, and the certainty of evidence was evaluated using the CINeMA framework. Results: Of 9844 records screened, 24 randomized controlled trials (3017 participants) met the inclusion criteria, encompassing 16 intervention categories. Network analysis ranked quince, vitamin B6 with pomegranate and mint, acupressure P6, dimenhydrinate, and acupuncture combined with doxylamine-pyridoxine as the most effective interventions for reducing symptoms of nausea and vomiting in pregnancy, with considerable uncertainty and low-to-moderate quality of evidence. Reporting of adverse events was limited. Risk of bias was low to moderate. Discussion: Most interventions demonstrated significant benefit over a placebo. However, high heterogeneity and sparse reporting of adverse effects warrant caution when translating these results into clinical practice. Conclusions: This study indicates that both pharmacological (vitamin B6, metoclopramide, dimenhydrinate) and non-pharmacological (ginger, quince, acupressure, acupuncture) interventions might be effective in reducing symptoms of nausea and vomiting in pregnancy.
Abstract licence: CC BY
Anees Bahji, Emily Kasurak, Morgan Sterling, et al.
Journal of Psychiatric Research, 2020
- Dimenhydrinate
- Psychotic Disorders
C. E. Gloria, Francis V. Roasa, Norberto Martinez
2017
Arne W. Scholtz, Frank Waldfahrer, Regina Hampel, et al.
Clinical Drug Investigation, 2022
- Cinnarizine
- Dimenhydrinate
- Betahistine
Mir Mohammad Jalali, Hooshang Gerami, Alia Saberi, et al.
Annals of Otology Rhinology & Laryngology, 2019
- Betahistine
- Dimenhydrinate
- Dizziness
Arne W. Scholtz, Aleš Hahn, Bohdana Stefflova, et al.
Clinical Drug Investigation, 2019
- Betahistine
- Cinnarizine
- Dimenhydrinate
Shin CW, Ambros B
2026
ObjectiveTo determine the antinausea and antiemetic effects of dimenhydrinate and maropitant in dogs when administered 60 minutes before hydromorphone and dexmedetomidine.Study designProspective, randomized, blinded, placebo-controlled clinical trial.AnimalsA total of 87 healthy client-owned dogs undergoing ovariectomy/castration.MethodsDogs were randomly assigned to be administered maropitant (1 mg kg-1; group M) subcutaneously (SC), dimenhydrinate (4 mg kg-1; group D) intramuscularly (IM), or 0.9% NaCl (0.1 mL kg-1; group C) SC 60 minutes before anesthetic premedication with hydromorphone (0.1 mg kg-1) and dexmedetomidine (5-15 μg kg-1) IM. Incidences of discomfort after injection of the treatment drug, nausea (ptyalism, lip licking, and swallowing), and vomiting/retching were documented. Scores for nausea and sedation were assigned immediately before premedication and for 20 minutes after premedication. Data were analyzed using Fisher's Exact test and Kruskal-Wallis test, with statistical significance set at pResultsDiscomfort to injection was significantly higher in group M (20/31, 64.5%) than in groups D (6/28, 21.4%) and C (2/28, 7.1%) (pConclusions and clinical relevanceDimenhydrinate produced no measurable antinausea and antiemetic effect when administered 60 minutes before hydromorphone and dexmedetomidine. Maropitant SC prevented hydromorphone-induced emesis but was ineffective in reducing nausea.
Abstract licence: CC BY-NC-ND
Sources: aggregated from Europe PMC (EMBL-EBI), OpenAlex, Crossref, PubMed and other open scholarly databases. Retracted articles are excluded. Study information is provided for research purposes and does not constitute medical advice.
Pharmacology and chemical data from DrugBank
Key facts
Drug status
Approved
Major interactions
1 found
Half-life
5-8 hours
Mechanism
Dimenhydrinate is a theoclate salt that separates into [diphenhydramine] and [8-chlorotheophylline].
Food interactions
1 warning
Human targets
1 target
Data: DrugBank · CC BY-NC 4.0
Pharmacokinetics at a glance
Absorption
50 mg
Half-life
5-8 hours
[L33000]
Protein binding
70-85%
[L33000]
Volume of distribution
3-4 L/kg
[L33000]
Metabolism
[L32985]…
Elimination
1-3%
[L33000]
1-3% of the dissociated diphenhydramine is eliminated in the urine unchanged,…
Pharmacokinetic data: DrugBank · CC BY-NC 4.0
Dimenhydrinate, also known as B-dimethylaminoethyl benzohydrol ether 8-chlorotheophyllinate, is indicated to prevent nausea, vomiting, and dizziness caused by motion sickness.[L32980][L32985][L32995] Dimenhydrinate is a combination of [Diphenhydramine] and [8-chlorotheophylline] in a salt form, with 53%-55.5% dried diphenhydramine, and 44%-47% died 8-chlorotheophylline.[L32985]
The antiemetic properties of dimenhydrinate are primarily thought to be produced by diphenhydramine's antagonism of H1 histamine receptors in the vestibular system[A1540] while the excitatory effects are thought to be produced by 8-chlorotheophylline's adenosine receptor blockade.[A33889]
When used in large doses, dimenhydrinate has been shown to cause a "high" characterized by hallucinations, excitement, incoordination, and disorientation.[A1539]
Dimenhydrinate was granted FDA approval on 31 May 1972.[L32975]
[L32980][L32985]
Known interactions with other medications. Always consult a healthcare professional.
Showing 50 of 979 interactions
[L32985]
Adults experiencing an overdose may present with drowsiness, convulsions, coma, or respiratory depression.
[L32985]
Treat overdoses with symptomatic and supportive measures including mechanically assisted ventilation.
[L32985]
In mice the oral LD50 is 203 mg/kg, while in rats it is 1320 mg/kg.
[L32985]
The intraperitoneal LD50 in mice is 149 mg/kg.
[L32985]
How the body processes this drug — absorption, distribution, metabolism, and elimination
[L33000]
A 100 mg suppository reaches a Cmax of 112.2 ng/mL with a Tmax of 5.3 hours.
[L33010]
[L33000]
[L33000]
[L33000]
[L32985]
diphenhydramine can either be N-glucuronidated by UGTs to diphenhydramine N-glucuronide or N-demethylated by CYP2D6, CYP1A2, CYP2C9, and CYP2C19 to N-desmethyldiphenhydramine.
[A415]
N-desmethyldiphenhydramine can be N-demethylated again by the same enzymes to N,N-didesmethyldiphenhydramine, which undergoes oxidative deamination to form diphenylmethoxyacetic acid.
[A415]
[L33000]
1-3% of the dissociated diphenhydramine is eliminated in the urine unchanged, while 64% of diphenhydramine is eliminated in the urine as metabolites.
[L33010]
The elimination of dimenhydrinate has not been fully studied.
[L33010]
Proteins and enzymes this drug interacts with in the body
PMID:33828102 PMID:8280179
Through the H1 receptor, histamine mediates the contraction of smooth muscles and increases capillary permeability due to contraction of terminal venules. Also mediates neurotransmission in the central nervous system and thereby regulates circadian rhythms, emotional and locomotor activities as well as cognitive functions (By similarity)
ATC R06AA11
ATC R06AA61
Chemical identifiers
CAS, UNII, InChI Key and database cross-references
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Chemical identifiers
CAS, UNII, InChI Key and database cross-references
Linked compound data from DrugBank Open Data (CC BY-NC 4.0)
Dimenhydrinate
Additional database identifiers
Drugs Product Database (DPD)
9782
ChemSpider
10210
HUGO Gene Nomenclature Committee (HGNC)
HGNC:5182
GenAtlas
HRH1
GeneCards
HRH1
GenBank Gene Database
Z34897
GenBank Protein Database
510296
Guide to Pharmacology
262
UniProt Accession
HRH1_HUMAN
DrugBank citations
If you use DrugBank data in your research, please cite the following publications:
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Structured knowledge from the free knowledge base
Linked open data from Wikidata (Q420439), a free and open knowledge base operated by the Wikimedia Foundation. Data is available under the Creative Commons CC0 1.0 Public Domain Dedication. WHO INN from the World Health Organization.