Dimenhydrinate is a type of medicine called an antihistamine.

Dimenhydrinate overdose occurs when someone accidentally or intentionally takes more than the normal or recommended amount of this medication.

This is for information only and not for use in the treatment or management of an actual poison exposure. If you have an exposure, you should call your local emergency number (such as 911) or the National Poison Control Center at 1-800-222-1222.

Dimenhydrinate

Dimenhydrinate is an ingredient found in some allergy medicines, as well as medicines used to treat nausea, vomiting, and seasickness.

It may be found in:

• Calm-X
• Dimetabs
• Dramamine
• Gravol
• Hydrate bullet
• Marmine
• Nico-Vert
• Triptone

Note: This list may not be all-inclusive.

• Blurred vision
• Breathing difficulty
• Convulsions
• Depression
• Delirium
• Dilated pupils
• Disorientation
• Drowsiness
• Dry mouth, nose, and other mucus membranes
• Dry, flushed, red skin
• Excitation
• Hallucinations
• Low blood pressure
• Nervousness
• Rapid heartbeat
• Seizures
• Tremor
• Unsteadiness
• Unconsciousness

Determine the following information:

• Patient's age, weight, and condition
• Name of the product (ingredients and strengths, if known)
• Time it was swallowed
• Amount swallowed
• If the medicine was prescribed for the patient

The National Poison Control Center (1-800-222-1222) can be called from anywhere in the United States. This national hotline number will let you talk to experts in poisoning. They will give you further instructions.

This is a free and confidential service. All local poison control centers in the United States use this national number. You should call if you have any questions about poisoning or poison prevention. It does NOT need to be an emergency. You can call for any reason, 24 hours a day, 7 days a week.

See: Poison control center - emergency number

The health care provider will measure and monitor the patient's vital signs, including temperature, pulse, breathing rate, and blood pressure. Symptoms will be treated as appropriate.

The patient may receive:

• Activated charcoal
• Antidote (medicine to reverse the effects of the antihistamine)
• Tube from the mouth into the stomach to empty the stomach (gastric lavage)

Recovery is likely if the patient survives the first 24 hours. Few patients actually die from an antihistamine overdose.

Scharman EJ, Erdman AR, Wax PM, et al. Diphenhydramine and dimenhydrinate poisoning: an evidence-based consensus guideline for out-of-hospital management. Clin Toxicol. 2006;44(3):205-223.