Dextromethorphan and doxylamine

Name: Dextromethorphan and doxylamine

What should I discuss with my healthcare provider before taking dextromethorphan and doxylamine?

You should not use this medicine if you are allergic to dextromethorphan or doxylamine.

Do not use dextromethorphan and doxylamine if you have used an MAO inhibitor in the past 14 days. A dangerous drug interaction could occur. MAO inhibitors include isocarboxazid, linezolid, methylene blue injection, phenelzine, rasagiline, selegiline, tranylcypromine, and others.

Do not give this medication to a child younger than 4 years old. Always ask a doctor before giving a cough or cold medicine to a child. Death can occur from the misuse of cough and cold medicines in very young children.

You should not use antihistamine medication to make a child sleepy.

To make sure dextromethorphan and doxylamine is safe for you, tell your doctor if you have:

  • high blood pressure, heart disease;

  • a thyroid disorder;

  • a blockage in your digestive tract (stomach or intestines);

  • liver or kidney disease;

  • diabetes;

  • cough with mucus, or cough caused by emphysema or chronic bronchitis;

  • bladder obstruction or other urination problems; or

  • if you take potassium (Cytra, Epiklor, K-Lyte, K-Phos, Kaon, Klor-Con, Polycitra, Urocit-K).

It is not known whether dextromethorphan and doxylamine will harm an unborn baby. Ask a doctor before using this medicine if you are pregnant.

Dextromethorphan and doxylamine may pass into breast milk and may harm a nursing baby. Antihistamines may also slow breast milk production. Ask a doctor before using this medicine if you are breast-feeding.

Artificially sweetened cough or cold medicine may contain phenylalanine. If you have phenylketonuria (PKU), check the medication label to see if the product contains phenylalanine.

What other drugs will affect dextromethorphan and doxylamine?

Ask a doctor or pharmacist before using this medicine if you are also using any other drugs, including prescription and over-the-counter medicines, vitamins, and herbal products. Some medicines can cause unwanted or dangerous effects when used together. Not all possible interactions are listed in this medication guide.

Taking this medicine with other drugs that make you sleepy or slow your breathing can worsen these effects. Ask your doctor before taking dextromethorphan and doxylamine with a sleeping pill, narcotic pain medicine, muscle relaxer, or medicine for anxiety, depression, or seizures.

What are some side effects that I need to call my doctor about right away?

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

  • Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.

What are some other side effects of this drug?

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

  • Feeling sleepy.
  • Feeling nervous and excitable.

These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.

You may report side effects to the FDA at 1-800-FDA-1088. You may also report side effects at http://www.fda.gov/medwatch.

Some side effects of dextromethorphan / doxylamine may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

Usual Adult Dose for Cough and Nasal Congestion

Dextromethorphan-doxylamine 15 mg-6.25 mg/15 mL oral liquid:
30 mL orally every 6 hours not to exceed 4 doses daily.

Dextromethorphan-doxylamine 7.5 mg-3.125 mg/5 mL oral liquid:
20 mL orally every 6 hours not to exceed 4 doses daily.

Renal Dose Adjustments

Data not available

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