Dextromethorphan, pheniramine, and phenylephrine

Generic name: dextromethorphan, pheniramine, and phenylephrine [ DEX-troe-meth-OR-fan, fen-IR-a-meen, and-FEN-il-EF-rin ]
Brand names: Alahist-DM, Hot Lemon Cough and Colds Relief DM, Theraflu Cold and Cough
Dosage form: oral liquid (10 mg-12.5 mg-5 mg/5 mL)
Drug class: Upper respiratory combinations

Medically reviewed by Drugs.com on Nov 14, 2023. Written by Cerner Multum.

What is dextromethorphan, pheniramine, and phenylephrine?

Dextromethorphan, pheniramine, and phenylephrine is a combination medicine used to treat cough, runny or stuffy nose, sneezing, itching, and watery eyes caused by allergies, the common cold, or the flu.

Dextromethorphan, pheniramine, and phenylephrine may also be used for purposes not listed in this medication guide.

Dextromethorphan, pheniramine, and phenylephrine side effects

Get emergency medical help if you have signs of an allergic reaction: hives, difficult breathing, swelling of your face, lips, tongue, or throat.

Stop using dextromethorphan, pheniramine, and phenylephrine and call your doctor at once if you have:

• dizziness;

• nervousness; or

• sleep problems (insomnia).

Less serious side effects may be more likely, and you may have none at all.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Related/similar drugs

Warnings

Do not use this medicine if you are using or 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, and tranylcypromine.

Before taking this medicine

Do not use dextromethorphan, pheniramine, and phenylephrine if you are using or 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, and tranylcypromine.

Ask a doctor or pharmacist if this medicine is safe to use if you have:

• high blood pressure, heart disease;

• glaucoma;

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

• urination problems due to an enlarged prostate;

• overactive thyroid; or

• diabetes.

Ask a doctor before using this medicine if you are pregnant or breastfeeding.

How should I take dextromethorphan, pheniramine, and phenylephrine?

Use exactly as directed on the label, or as prescribed by your doctor. Cold or cough medicine is only for short-term use.

Do not give this medicine to a child without medical advice. Follow all directions when giving this medicine to a child. Do not use the medicine to make a child sleepy. Misuse of this medicine may cause death in very young children.

Measure liquid medicine with the supplied measuring device (not a kitchen spoon).

Call your doctor if your symptoms do not improve after 7 days, or if you have a fever, rash, or headaches.

Store at room temperature away from moisture and heat.

Dextromethorphan, pheniramine, and phenylephrine dosing information

Usual Adult Dose for Cold Symptoms:

Dextromethorphan/pheniramine/phenylephrine 20 mg-20 mg-10 mg oral powder:
Dissolve 1 packet in 8 ounces of hot water and drink in 10 to 15 minutes. May repeat every 4 hours. Not to exceed 6 packets daily.

Usual Pediatric Dose for Cold Symptoms:

Dextromethorphan/pheniramine/phenylephrine 20 mg-20 mg-10 mg oral powder:
>=12 yrs: Dissolve 1 packet in 8 ounces of hot water and drink in 10 to 15 minutes. May repeat every 4 hours. Not to exceed 6 packets daily.

What happens if I miss a dose?

dextromethorphan, pheniramine, and phenylephrine is used when needed. If you are on a dosing schedule, skip any missed dose. Do not use two doses at one time.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while taking dextromethorphan, pheniramine, and phenylephrine?

Drinking alcohol with dextromethorphan, pheniramine, and phenylephrine can cause side effects.

Ask a doctor or pharmacist before taking other cough or cold medicines that may contain similar ingredients.

Avoid driving or hazardous activity until you know how this medicine will affect you. Your reactions could be impaired.

What other drugs will affect dextromethorphan, pheniramine, and phenylephrine?

Ask a doctor or pharmacist before using any other medicines that can cause drowsiness (such as opioid medication, sleep medicine, a muscle relaxer, or medicine for anxiety or seizures). Tell your doctor about all other medicines you use. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed here.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer

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