Dimenhydrinate (first-generation antihistamine)

Dimenhydrinate is a first-generation antihistamine. It blocks histamine in the body, reducing the severity of allergy symptoms such as skin rash, runny nose, and watery eyes. It also has sedative properties and reduces nausea and vomiting due to vertigo.

Uses

What is Dimenhydrinate used for?

• Motion sickness
• Nausea and vomiting due to vertigo
• Allergic conditions
• Meniere’s disease

How should I take Dimenhydrinate?

Read the directions on the packaging for complete information. Check the label and expiration date.

For regular oral tablets, swallow it whole without chewing, crushing, or dissolving it in liquid.

If you are taking chewable tablets, chew the tablet completely, swallow, and then drink a glass of water. It is best taken after meals and at bedtime. Do not swallow the tablet whole or dissolve it in liquid.

For parenteral dosage forms, only a licensed healthcare professional should administer it.

How do I store Dimenhydrinate?

Store this product at room temperature away from direct light and moisture. To prevent drug damage, you should not store it in the bathroom or the freezer. 

There may be different brands of this drug that may have different storage needs. So, it is important to always check the product package for instructions on storage, or ask your pharmacist. For safety, you should keep all medicines away from children and pets.

You should not flush this product down the toilet or pour them into a drain unless instructed to do so. Additionally, it is important to properly discard this product when it is expired or no longer needed. Consult your pharmacist for more details about how to safely discard your product.

Precautions & warnings

What should I know before using Dimenhydrinate?

Before using this drug, tell your doctor if you are/have:

• Pregnant or breastfeeding.
• Taking any other medicines. This includes any prescription, OTC, and herbal remedies.
• An allergy to any of the ingredients of this product.
• Any other illnesses, disorders, or medical conditions.

Is it safe during pregnancy or breast-feeding?

Unfortunately, there isn’t enough information about the safety of using this drug during pregnancy and breastfeeding. However, it is likely safe to take. Please always consult with your doctor to weigh the potential benefits and risks before taking any medication.

This medication is pregnancy risk category B according to the US Food and Drug Administration (FDA).

FDA pregnancy risk category reference below:

• A= No risk
• B= No risk in some studies
• C= There may be some risk
• D= Positive evidence of risk
• X= Contraindicated
• N= Unknown

Side effects

What side effects can occur from Dimenhydrinate?

Like all drugs, this product may have side effects. If they occur, side effects are generally mild and resolve once treatment is finished or the dose is lowered. Some reported side effects include:

• Chest tightness
• Palpitations
• Tachycardia (fast heart rate)
• Sweating
• Skin rash
• Decreased appetite
• GI disturbances
• Dry mouth
• Changes in urination
• Dizziness
• Drowsiness
• Excitation
• Tremor
• Blurred vision
• Tinnitus
• Insomnia
• Memory impairment
• Cognitive dysfunction

However, not everyone experiences these side effects. In addition, some people may experience other side effects. So, if you have any concerns about a side effect, please consult your doctor or pharmacist.

Interactions

What drugs may interact with Dimenhydrinate?

This medication may interact with other drugs that you are currently taking, which can change how your drug works or increase your risk for serious side effects.

To avoid any potential drug interactions, you should keep a list of all the drugs you are using (including prescription drugs, nonprescription drugs, and herbal products) and share it with your doctor and pharmacist.

Drugs with known interactions:

• Other antihistamines
• CNS depressants
• MAOIs
• Anticholinergic agents

If you experience an adverse drug interaction, inform your doctor immediately to reevaluate your treatment plan. Approaches include dose adjustment, drug substitution, or ending therapy.

Does food or alcohol interact with Dimenhydrinate?

This drug may interact with food or alcohol by altering the way the drug works or increase the risk for serious side effects. Do not consume alcohol. Please discuss with your doctor or pharmacist any potential food or alcohol interactions before using this drug.

What health conditions may interact with Dimenhydrinate?

This drug may interact with underlying conditions. This interaction may worsen your health condition or alter the way the drug works. Therefore, it is important to always let your doctor and pharmacist know all the health conditions you currently have.

Dosage

The information provided is not a substitute for any medical advice. Therefore, you should always consult with your doctor or pharmacist before using any medication.

What is the dose for an adult?

Nausea and vertigo caused by Meniere’s disease & treatment of motion sickness:

Oral

Take 50-100 mg every 6-8 hours.

To prevent motion sickness, take one dose 30-60 minutes prior to activity or traveling.

IV/IM

Administer 50-100 mg every 4 hours. Maximum dose of 100 mg every 4 hours.

For IV solution reconstitution:

Dilute a 50 mg vial with 10 mL of 0.9% NaCl solution.

What is the dose for a child?

Nausea and vertigo caused by Meniere’s disease & treatment of motion sickness:

Oral

• Age 2-6 years: Give 12.5 to 25 mg every 6-8 hours. Maximum dose of 75 mg per day.
• 6 to 11 years: Give 50 mg every 6 to 8 hours. Maximum dose of 150 mg per day.
• 12 years and above: the same as the adult dose.

To prevent motion sickness, give one dose 30-60 minutes prior to activity or traveling.

IM

Administer 1.25 mg/kg or 37.5 mg/m² 4 times a day. Maximum dose of 300 mg per day.

How is Dimenhydrinate available?

Dimenhydrinate is available in the following brands, dosage forms, and formulations:

• Solution for injection: 50 mg/mL
• Tablet: 50 mg
• Chewable tablet: 50 mg

What should I do in case of an emergency or overdose?

In case of an emergency or an overdose, call your local emergency services or go to your nearest emergency room.

What should I do if I miss a dose?

If you miss a dose of dimenhydrinate, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and take your regular dose as scheduled. Do not take a double dose.