dextromethorphan hydrobromide + diphenhydramine hydrochloride at a glance
Medicine class
Centrally acting cough suppressant plus sedating antihistamine.
Licensed use
Night-time relief of dry cough and congestive symptoms associated with colds.
Age restriction
Must not be given to children under 12 years.
Driving and alcohol
May cause sleepiness, dizziness and impaired concentration. Do not drive if affected, and avoid alcohol.
What is dextromethorphan hydrobromide + diphenhydramine hydrochloride used for?
The selected product is licensed for night-time symptom relief.
Dry or unproductive cough associated with a cold.
Accompanying congestive cold symptoms.
How does dextromethorphan hydrobromide + diphenhydramine hydrochloride work?
Dextromethorphan acts in the brainstem to suppress the cough reflex. Diphenhydramine blocks histamine H1 receptors and has sedating and antimuscarinic effects, which may reduce a runny nose but can cause drowsiness and dry mouth.
How to take dextromethorphan hydrobromide + diphenhydramine hydrochloride
Shake the bottle and swallow the oral solution, following its label. Measure it with an appropriate device rather than a household spoon. Do not combine it with another cough-and-cold product or alcohol.
Check cough, cold and night-time products for duplicate dextromethorphan, diphenhydramine or other sedating ingredients.
Do not drive, cycle or operate machinery if sleepy, dizzy or unable to concentrate.
dextromethorphan hydrobromide + diphenhydramine hydrochloride side effects
Common or expected effects
- Sleepiness or daytime drowsiness
- Dry mouth or thickened secretions
- Dizziness, unsteadiness or difficulty concentrating
- Nausea, vomiting or diarrhoea
- Headache or blurred vision
Get urgent medical advice
- Severe allergic reaction or breathing difficulty
- Seizures, severe confusion, hallucinations or marked agitation
- Slow or difficult breathing
- Fast or irregular heartbeat
- Acute eye pain or visual disturbance
- Inability to pass urine
- Symptoms suggesting serotonin syndrome
dextromethorphan hydrobromide + diphenhydramine hydrochloride in pregnancy
Use during pregnancy is not advised unless there is a clear clinical need. Ask a doctor or pharmacist before use.
dextromethorphan hydrobromide + diphenhydramine hydrochloride while breastfeeding
The selected combination is best avoided while breastfeeding because diphenhydramine enters breast milk and information about dextromethorphan transfer is limited. Seek professional advice before use.
dextromethorphan hydrobromide + diphenhydramine hydrochloride interactions
Check prescribed, pharmacy and recreational substances before use because important serotonergic, sedative and antimuscarinic interactions can occur.
Monoamine oxidase inhibitors, including phenelzine, moclobemide and rasagiline
Do not combine or use within two weeks of an MAOI because a severe interaction and serotonin syndrome may occur.
Selective serotonin reuptake inhibitors
The selected product is contraindicated because serotonin syndrome may occur.
CYP2D6 inhibitors, including fluoxetine, paroxetine, quinidine, terbinafine and bupropion
May increase dextromethorphan exposure and the risk of confusion, agitation, tremor, respiratory depression and serotonin syndrome.
Common questions about dextromethorphan hydrobromide + diphenhydramine hydrochloride
Answers are fully visible for fast scanning and source review.
Can it make me sleepy?
Yes. Sleepiness, dizziness and reduced concentration can occur.
Can I drink alcohol with it?
No. Alcohol can increase sedation, central nervous system effects and toxicity.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.