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Over-the-counter (OTC) medicines are medicines you can buy without a prescription from your healthcare provider. Medicines that treat nausea and vomiting are called antiemetics. Several OTC medicines are used as antiemetics. These include:

• Bismuth subsalicylate (some brand names: Kaopectate, Pepto-Bismol) may help treat some types of nausea and vomiting, such as from gastroenteritis (also called “stomach flu”). It’s also used for upset stomach and as an antidiarrheal (medicine to treat diarrhea).
• Certain antihistamines may help prevent nausea and vomiting caused by motion sickness. This includes dimenhydrinate (brand name: Gravol).

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How do antiemetic medicines work?

Bismuth subsalicylate works by protecting the stomach lining.

Antihistamines appear to dull the inner ear’s ability to sense motion. They “block” messages to the part of the brain that controls nausea and vomiting. This is why they work best if you take them before you think you might have a problem with motion sickness.

How do I safely take OTC antiemetic medicines?

Before you take an OTC antiemetic medicine, read the directions on the drug facts label. This will tell you how much medicine to take and how often to take it. If you have any questions about how much medicine to take, contact your healthcare provider or pharmacist. Keep a record of the OTC medicines you are using and when you take them. If you need to go to the healthcare provider, take this list with you.

Follow these tips to make sure you are taking the right amount of medicine:

• Take only the amount recommended on the medicine’s label. Don’t assume that more medicine will work better or quicker. Taking more than the recommended amount can be dangerous.
• If you are taking a prescription medicine, ask your healthcare provider if it’s okay to also take an OTC antiemetic medicine.
• Don’t use more than 1 kind of OTC antiemetic medicine at a time unless your healthcare provider says it’s okay. They may have similar active ingredients that add up to be too much medicine.

How can I safely store OTC antiemetic medicines?

Store all medicines up and away, out of reach and sight of young children. Keeping medicines in a cool, dry place will help prevent them from becoming less effective before their expiration dates. Do not store medicines in bathrooms or bathroom cabinets, which are often hot and humid.

Things to consider

Healthy adults usually don’t experience side effects from antiemetic medicines. Side effects can be a concern for older adults or people who have health problems.

The most common side effects of bismuth subsalicylate are:

• Darkened stools or tongue,
• Constipation,
• Ringing sound in the ears (tinnitus).

These are short-term side effects.

Antihistamines may make you feel sleepy. This can affect your ability to drive or operate machines. It may be hard for you to think clearly. Alcohol can increase the drowsiness caused by antihistamines. They may also cause your mouth and eyes to feel dry.

Who shouldn’t take OTC antiemetic medicines?

Some people are allergic to aspirin or other salicylate medicines. They shouldn’t take bismuth subsalicylate. Don’t give bismuth subsalicylate to children 12 years of age or younger. Don’t give bismuth subsalicylate to children or teenagers 12 to 18 years of age who may have the flu or chickenpox. This increases their risk for Reye syndrome, which is a serious illness that can lead to death.

Before taking an antihistamine, talk to your healthcare provider if you have any of the following problems:

• Glaucoma.
• Trouble urinating (from an enlarged prostate gland).
• Breathing problems, such as asthma, emphysema, or chronic bronchitis.
• Thyroid disease.
• Heart disease.
• High blood pressure.

Can OTC antiemetic medicines cause problems with any other medicines I take?

Bismuth subsalicylate may affect some medicines so that they don’t work as well. It also may cause side effects if combined with other medicines. Contact your healthcare provider before taking bismuth subsalicylate if you also take:

• Blood-thinning medicines
• Medicines for gout
• Medicines for arthritis
• Medicines for diabetes

Ask your healthcare provider before taking bismuth subsalicylate if you take pain relievers or cold medicines. These medicines may contain aspirin, which is a salicylate. You may get too much salicylate if you take more than 1 of these medicines at a time.

Contact your healthcare provider before taking an antihistamine if you take sleeping pills, sedatives, or muscle relaxants. Many OTC cold and allergy medicines contain antihistamines. If you take more than 1 of these medicines, you may take more antihistamine than you intend.

Some prescription medicines have side effects similar to the side effects of antihistamines (including dry mouth and drowsiness), so you should also talk with your healthcare provider before taking these medicines at the same time.