GUAPHAN SYRUP 100ML

Indications

Approved Uses

Symptomatic relief of cough associated with upper respiratory tract infections/common cold with chest congestion (expectorant effect) and suppression of non-productive cough (antitussive effect).

Dosage & Administration

Dosing by Condition

Cough/chest congestion (immediate-release syrup): Adults and children ≥12 years: 10 mL every 4 hours as needed (max 6 doses/24 h = 60 mL/day). Children 6-11 years: 5 mL every 4 hours as needed (max 6 doses/24 h = 30 mL/day). Children 2-5 years: 2.5 mL every 4 hours as needed (max 6 doses/24 h = 15 mL/day).

Initial Dose

Adults and children ≥12 years: 10ml (200mg guaifenesin + 20mg dextromethorphan) every 4-6 hours

Maintenance Dose

10ml every 4-6 hours as needed in adults

Maximum Dose

Do not exceed 6 doses (60 mL) in 24 hours for adults and ≥12 years (equivalent to 1200 mg guaifenesin + 120 mg dextromethorphan per day at 100 mg/mL and 10 mg/mL).

Dose Adjustment Notes

No routine renal or hepatic dose adjustment is established for short-term use; no specific guidance for hepatic impairment.

Side Effects

Common Side Effects

Dizziness, drowsiness/somnolence, nausea, vomiting, and gastrointestinal upset (e.g., abdominal pain; diarrhea can occur).

Side Effect Frequency

Common: dizziness, drowsiness/somnolence, nausea, vomiting, gastrointestinal upset. Uncommon: rash/urticaria or other hypersensitivity reactions. Rare/serious: serotonin syndrome (especially with serotonergic drugs/MAOIs), CNS/respiratory depression primarily with overdose or misuse.

Safety & Warnings

Contraindications

Contraindicated with concomitant MAOI use or within 14 days of stopping an MAOI; contraindicated in patients with known hypersensitivity to guaifenesin or dextromethorphan.

Warnings & Precautions

Avoid MAOIs and for 14 days after stopping; caution with other serotonergic drugs (serotonin syndrome risk); may cause drowsiness-avoid alcohol/CNS depressants and use caution driving; consult a clinician if cough persists >7 days/recurs or is accompanied by fever/rash/headache; use caution in chronic cough (asthma/COPD/smoking) or excessive secretions; use caution in hepatic impairment; do not exceed recommended dose.

Age Restriction

Not recommended for children under 4 years of age (unless specifically directed by a physician).

Driving Warning

May Cause Drowsiness

Drug Interactions

Drug Interactions

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

Interaction Severity

MAJOR/Contraindicated: MAO inhibitors (and within 14 days of stopping) due to risk of serotonin syndrome/hypertensive reactions. MODERATE: other serotonergic drugs (SSRIs/SNRIs/TCAs, linezolid, triptans, etc.)-serotonin syndrome risk; strong CYP2D6 inhibitors (e.g., fluoxetine, paroxetine, quinidine) can increase dextromethorphan exposure; CNS depressants (alcohol, opioids, benzodiazepines) may increase sedation/impairment.

Alcohol Interaction

Avoid

Special Populations

Elderly

No specific dose adjustment is needed for older adults.

Kidney Impairment

No adjustment needed.

Liver Impairment

No dose adjustment is advised in the manufacturer label for patients with hepatic impairment.

Storage & Patient Advice

Stopping the Medicine

May be stopped when symptoms resolve; no tapering is required. Seek medical advice if cough persists >7 days, recurs, or is accompanied by fever, rash, or persistent headache.

Overdose

Symptoms: nausea/vomiting, dizziness, ataxia, agitation/confusion, hallucinations, tachycardia, hypertension, CNS depression, and in severe cases respiratory depression and serotonin syndrome; Management: urgent medical evaluation, supportive care, activated charcoal if early, benzodiazepines for agitation/seizures, and naloxone may be considered for significant CNS/respiratory depression.

Patient Counseling

Shake well; measure with a calibrated device. Maintain adequate fluids. Do not exceed recommended dose or combine with other cough/cold products containing dextromethorphan. Avoid alcohol and other sedatives; may cause drowsiness-use caution driving. Do not use with MAOIs or within 14 days of stopping. Seek medical advice if cough lasts >7 days, recurs, or is accompanied by fever, rash, persistent headache, shortness of breath, or thick/colored sputum. Store below 25°C and keep out of reach of children.

Monitoring Requirements

No routine monitoring required. Monitor for signs of serotonin syndrome if used with serotonergic agents.

Pharmacology

Mechanism of Action

Guaifenesin is an expectorant that increases hydration of respiratory secretions and reduces mucus viscosity to aid clearance. Dextromethorphan is a centrally acting antitussive that suppresses the medullary cough center (via sigma-1 activity and NMDA antagonism at higher relevance).

Duration of Effect

Approximately 4 hours (up to 6 hours) for immediate-release syrup.

Bioavailability

Guaifenesin: rapidly absorbed orally; short half-life (~1 hour). Dextromethorphan: well absorbed but undergoes extensive first-pass metabolism via CYP2D6 with highly variable systemic exposure (poor metabolizers have higher levels); absolute bioavailability is low/variable and not reliably stated as a single fixed percentage.

Metabolism

Guaifenesin: rapidly metabolized (primarily hepatic) to inactive metabolites. Dextromethorphan: extensive hepatic metabolism mainly via CYP2D6 to dextrorphan (active) and also via CYP3A4 (and subsequent conjugation).

Protein Binding

Unknown / not well characterized for both guaifenesin and dextromethorphan in standard labeling.

Product Information

Available Dosage Forms

Syrup (oral).

Composition per Dose

Each 5ml: Guaifenesin 100mg + Dextromethorphan HBr 10mg

OTC Alternatives

OTC alternatives may exist as single-ingredient guaifenesin or dextromethorphan products (availability depends on local Saudi regulatory classification); however, this specific product is SFDA-classified as Prescription.

Symptom Target

Cough, Congestion, Multi-symptom

Sedating

Yes

Reviewed by Al Mujtama Pharmacy Medical Review Team. Last reviewed 17-08-2026