RIAPHAN SYRUP

Indications

Approved Uses

Symptomatic (temporary) relief of non-productive (dry) cough.

Dosage & Administration

Dosing by Condition

Cough (immediate-release dextromethorphan 15 mg/5 mL syrup): Adults and children ≥12 years: 10 mL (30 mg) every 6-8 hours (max 120 mg/day); Children 6-11 years: 5 mL (15 mg) every 6-8 hours (max 60 mg/day); Children 4-5 years: 2.5 mL (7.5 mg) every 8 hours (max 30 mg/day); <4 years: do not use.

Initial Dose

15 mg (5 ml) every 4-8 hours in adults

Maintenance Dose

Adults: 10 mL every 6-8 hours (not 15-30 mg every 4-8 hours); maximum 4 doses in 24 hours

Maximum Dose

120 mg per 24-hour period (not per day as stated; maximum 4 doses in 24 hours at 10 mL per dose for adults)

Children's Dosage

Children 6-12 years: 5-10 mL every 4-8 hours (not 2.5-5 mL); Children 4-6 years: 2.5-5 mL every 4-8 hours; Children under 4 years: do not use

How to Take

Shake well before use; measure the dose with a calibrated measuring device (oral syringe/cup); take by mouth with or without food; do not exceed the prescribed/recommended dose.

Side Effects

Common Side Effects

Drowsiness, dizziness, nausea, vomiting, and gastrointestinal upset/abdominal discomfort.

Safety & Warnings

Contraindications

Concomitant use with MAO inhibitors or within 14 days of stopping an MAOI; known hypersensitivity to dextromethorphan (or excipients).

Warnings & Precautions

Do not use with or within 14 days of MAOIs; avoid/use caution in chronic cough (e.g., asthma/COPD/smoking-related) or productive cough with excessive sputum unless evaluated; caution with serotonergic drugs (serotonin syndrome risk); caution with hepatic impairment and CYP2D6 poor metabolizers or CYP2D6 inhibitors; avoid alcohol/other CNS depressants; counsel on misuse/abuse potential.

Age Restriction

Not recommended in children under 4 years (and avoid under 2 years unless specifically directed by a physician).

Drug Interactions

Drug Interactions

MAOIs (contraindicated; serotonin syndrome/toxic reactions); serotonergic drugs (e.g., SSRIs/SNRIs/TCAs, linezolid, triptans) increase serotonin syndrome risk; strong CYP2D6 inhibitors (e.g., quinidine, fluoxetine, paroxetine, bupropion, amiodarone) can raise dextromethorphan exposure/toxicity; alcohol and other CNS depressants may increase sedation/impairment.

Special Populations

Children

Children 6-12 years: 5-10 mL every 4-8 hours (not 2.5-5 mL); Children 4-6 years: 2.5-5 mL every 4-8 hours; Children under 4 years: do not use

Storage & Patient Advice

Missed Dose

Take as soon as remembered; skip if near the time of the next dose. Do not double the dose

Patient Counseling

Use the provided measuring device for accurate dosing; do not exceed the recommended dose. Do not use with MAO inhibitors or within 14 days of stopping an MAOI. Avoid alcohol and other sedatives; may cause drowsiness-avoid driving/operating machinery until effects are known. Do not use for chronic cough (e.g., asthma/COPD/smoking-related) or a productive (wet) cough unless advised by a clinician. Seek medical advice if cough lasts >7 days or is accompanied by fever, rash, persistent headache, or breathing difficulty. Store below 30°C and keep out of reach of children.

Pharmacology

Mechanism of Action

Suppresses the cough reflex centrally by increasing the cough threshold in the medulla; acts as a sigma-1 receptor agonist and NMDA receptor antagonist (among other CNS actions).

Onset of Action

15-30 minutes.

Duration of Effect

Approximately 3-6 hours for immediate-release syrup.

Bioavailability

Oral bioavailability is low and variable due to extensive first-pass metabolism (commonly cited around ~10% in extensive metabolizers; higher in CYP2D6 poor metabolizers).

Excretion

Primarily renal, as metabolites.

Product Information

Available Dosage Forms

For RIAPHAN specifically: Syrup (oral).

Composition per Dose

Each 5 ml: Dextromethorphan hydrobromide 15 mg (equivalent to dextromethorphan 3 mg/ml)

Symptom Target

Cough

Sedating

Yes

Reviewed by Al Mujtama Pharmacy Medical Review Team. Last reviewed 06-06-2026