Cough · Cough suppressant (non-opioid)
Dextromethorphan
Dextromethorphan is an over-the-counter cough suppressant used for short-term relief of a dry, irritating cough.
OTCPregnancy: cautionKidney warningLiver warningAlcohol interactionSenior precautionOverview & typical uses
Dextromethorphan is an over-the-counter cough suppressant used for short-term relief of a dry, irritating cough.
Primary uses
- Temporary suppression of a dry, tickly cough associated with a cold
How it works
Acts on the cough centre in the brain to raise the cough threshold, without significantly affecting the airways.
Available forms & strengths
- Oral syrup — 15 mg / 5 mL (Oral)
- Lozenge — 7.5 mg, 15 mg (Oral)
General precautions & contraindications
Do not use if
- Current or recent MAOI use (within 14 days)
- Productive (wet, mucus-y) cough should not be routinely suppressed
Pregnancy
Use with caution — discuss with clinician. Occasional short-term use is usually acceptable; discuss regular use.
Breastfeeding
Use with caution — discuss with clinician. Limited data; brief short-term use is usually acceptable.
Kidney considerations
- Use with caution in kidney disease.
Liver considerations
- Use with caution in liver disease.
Paediatric use
Not recommended under 6 years.
Older adults
Watch for interactions with other cold-and-flu products.
Common side effects
- Drowsiness or mild dizziness
- Nausea
- Constipation
Serious warnings — seek help if these appear
- Serotonin-related side effects when combined with SSRIs, MAOIs, or other serotonergic medicines
- Serious allergic reaction (very rare)
Drug interactions
Risk of serious serotonin toxicity — do not combine.
Increased risk of serotonin syndrome.
Additive drowsiness.
Food & alcohol precautions
Increases drowsiness and impairs coordination.
Alcohol
- Alcohol may increase drowsiness and impair coordination.
Storage, missed dose & overdose
Storage
Store below 25 °C, out of reach of children.
If a dose is missed
Taken as needed for cough. If scheduled, take when remembered unless the next dose is near.
Overdose
Overdose can cause severe drowsiness, hallucinations, elevated heart rate, and serotonin toxicity. Seek urgent medical help.
What to monitor
- Do not use for a cough that produces significant mucus.
- Stop and see a clinician if cough persists beyond a week or worsens.
Frequently asked questions
It is designed for dry, tickly coughs. A wet, productive cough usually benefits more from fluids and expectorants.
Medical references
- British National Formulary — Dextromethorphan — BNF (NICE)
- FDA drug information — Dextromethorphan — U.S. Food & Drug Administration
Content last reviewed: 2025-01-01
Medical disclaimer
This information is for educational purposes only and should not replace professional medical advice. Please consult a licensed pharmacist or clinician for advice tailored to your personal circumstances.