Intramuscular, Intravenous Motion sickness, Nausea and vomiting, Vertigo
Adult: 50-100 mg 4 hourly via IM or IV inj over 2 minutes. Child: 1.25 mg/kg or 37.5 mg/m2 4 times daily via IM inj. Max: 300 mg daily.
Oral Motion sickness, Nausea and vomiting, Vertigo
Adult: 50-100 mg 4-6 hourly. Max: 300-400 mg daily. For prevention of motion sickness, give 30 minutes to 1 hour before activity. Dosage recommendations may vary among countries or individual products. Refer to specific product guidelines. Child: 2-5 years 12.5-25 mg 6-8 hourly. Max: 75 mg daily; 6-<12 years 25-50 mg 6-8 hourly. Max: 150 mg daily; ≥12 years Same as adult dose. Dosage recommendations may vary among countries or individual products. Refer to specific product guidelines.
Rectal Motion sickness, Nausea and vomiting, Vertigo
Adult: 1-2 supp (50-100 mg) 6-8 hourly. For prevention of motion sickness, insert into the rectum 30 minutes (preferably 1-2 hours) before travelling. Child: 8-12 years 1 supp (50 mg) 8-12 hourly.
Administration
tab: May be taken with or without food.
Reconstitution
IV: Dilute each mL (50 mg) of solution in 10 mL of 0.9% NaCl inj.
Incompatibility
IV: Incompatible with phenothiazine derivatives, reserpine, methoxamine hydrochloride, pentobarbital Na, thiamylal Na, nicotinic acid, pyridoxine hydrochloride and certain antibiotic solutions (e.g. chloramphenicol succinate). May cause precipitation when mixed with solutions of tetracycline hydrochloride in dextrose inj and when mixed with novobiocin Na in NaCl solution.
Special Precautions
Patient with CV disease (e.g. arrhythmias, hypertension, ischaemic heart disease), prostatic hyperplasia and/or genitourinary obstruction, pyloroduodenal obstruction (e.g. stenotic peptic ulcer), history of asthma or lower respiratory tract symptoms, seizure disorders, thyroid dysfunction, increased intraocular pressure or angle-closure glaucoma. Hepatic impairment. Children and elderly. Pregnancy and lactation.
Adverse Reactions
Significant: Sedation; excitation in children. Cardiac disorders: Tachycardia. Eye disorders: Blurred vision. Gastrointestinal disorders: Dry mouth, epigastric distress. General disorders and administration site conditions: Lassitude. Metabolism and nutrition disorders: Anorexia. Musculoskeletal and connective tissue disorders: Muscular weakness. Nervous system disorders: Dizziness, headache. Psychiatric disorders: Nervousness, restlessness, insomnia (especially in children). Renal and urinary disorders: Difficult or painful urination. Respiratory, thoracic and mediastinal disorders: Thickening of bronchial secretions, dry nose and throat. Skin and subcutaneous tissue disorders: Rash. Vascular disorders: Hypotension.
This drug may cause CNS depression (e.g. drowsiness, impaired mental alertness), if affected, do not drive or operate machinery.
Monitoring Parameters
Monitor for anticholinergic side effects (e.g. confusion, constipation).
Overdosage
Symptoms: Dilated pupils, flushed face, excitation, hallucinations, confusion, ataxia, intermittent clonic convulsions, coma, cardiorespiratory collapse (children); extreme difficulty in speech and swallowing, cycle of CNS excitation, seizures and postictal depression (adult). Management: Symptomatic and supportive treatment. In the absence of seizures, performing early gastric lavage (with an endotracheal tube with cuff inflated in place to prevent aspiration of gastric contents) is beneficial. In case of seizures, may give diazepam (in adults) or phenobarbital (in children). Mechanical respiratory assistance may be necessary.
Drug Interactions
May mask the warning symptoms of ototoxicity by ototoxic drugs (e.g. aminoglycoside antibiotics). May potentiate the effects of anticholinergic drugs (e.g TCAs) and antiparkinsonian drugs (e.g. trihexyphenidyl). May enhance the effects of CNS depressants (e.g. narcotic analgesics, barbiturates).
Food Interaction
May enhance the CNS depressant effect of alcohol.
Action
Description: Mechanism of Action: Dimenhydrinate is a monoethanolamine derivative with CNS depressant, anticholinergic, antiemetic, antihistaminic and local anaesthetic effects. Its exact mechanism of antiemetic action is unknown; however, it is believed to inhibit acetylcholine. It has a central anticholinergic activity that blocks the chemoreceptor trigger zone, diminishes vestibular stimulation, and reduces labyrinthine function. Additionally, it competes with histamine in binding for H1-receptor sites on effector cells in the gastrointestinal tract, blood vessels, and respiratory tract. Onset: Antiemetic: 15-30 minutes (oral); immediate (IV); 20-30 minutes (IM). Duration: 3-6 hours. Pharmacokinetics: Absorption: Well absorbed. Time to peak plasma concentration: 1-2 hours. Distribution: Widely distributed into body tissues. Crosses the placenta and enters breast milk. Volume of distribution: 3-4 L/kg. Plasma protein binding: 70-85%. Metabolism: Extensively metabolised in the liver to metabolites (diphenyl-methoxy-ethylamine, diphenyl-methoxy-acetic, diphenyl-methoxy-N-methylamine). Excretion: Via urine, as metabolites. Elimination half-life: 5-8 hours.
Chemical Structure
Dimenhydrinate Source: National Center for Biotechnology Information. PubChem Compound Summary for CID 10660, Dimenhydrinate. https://pubchem.ncbi.nlm.nih.gov/compound/Dimenhydrinate. Accessed Apr. 27, 2022.
R06AA11 - dimenhydrinate ; Belongs to the class of aminoalkyl ethers used as systemic antihistamines.
References
Anon. Dimenhydrinate. AHFS Clinical Drug Information [online]. Bethesda, MD. American Society of Health-System Pharmacists, Inc. https://www.ahfscdi.com. Accessed 02/02/2022.Anon. Dimenhydrinate. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 02/02/2022.Buckingham R (ed). Dimenhydrinate. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 02/02/2022.Dimenhydrinate Injection, Solution (Fresenius Kabi USA, LLC). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 02/02/2022.Dimenhydrinate Tablet (Cardinal Health). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 02/02/2022.Dimenhydrinate Tablet, Chewable (Lil' Drug Store Products, Inc.). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 02/02/2022.Driminate Suppository (Y.S.P. Industries [M] Sdn. Bhd.). National Pharmaceutical Regulatory Agency - Ministry of Health Malaysia. https://www.npra.gov.my. Accessed 02/02/2022.Dymenate Syrup (Dynapharm [M] Sdn. Bhd.). National Pharmaceutical Regulatory Agency - Ministry of Health Malaysia. https://www.npra.gov.my. Accessed 02/02/2022.Dymenate Tablet 50 mg (Dynapharm [M] Sdn. Bhd). National Pharmaceutical Regulatory Agency - Ministry of Health Malaysia. https://www.npra.gov.my. Accessed 02/02/2022.Gravol Capsule, Liquid Filled (Church & Dwight Co., Inc.). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 12/04/2022.Gravol Syrup (Church & Dwight Co., Inc.). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 12/04/2022.Pridrinate Suppositories (Prime Pharmaceutical Sdn. Bhd.). National Pharmaceutical Regulatory Agency - Ministry of Health Malaysia. https://www.npra.gov.my. Accessed 02/02/2022.Travlese (Chelonia Healthcare Limited). MHRA. https://products.mhra.gov.uk. Accessed 02/02/2022.
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