RIAPHYLLIN SYRUP 100ML

Indications

Approved Uses

Maintenance treatment of reversible airway obstruction associated with asthma and chronic obstructive pulmonary disease (including chronic bronchitis and emphysema).

Off-Label Uses

Off-label examples: central sleep apnea/Cheyne-Stokes respiration (limited evidence) and diaphragmatic dysfunction/fatigue (limited evidence).

Dosage & Administration

Dosing by Condition

Asthma/COPD (immediate-release oral): dosing is individualized and titrated to serum concentrations; typical adult starting total daily dose ~300 mg/day in divided doses, then titrate (often up to ~400-600 mg/day) based on response, tolerability, and serum levels.

Initial Dose

Adults (oral syrup 12 mg/mL): Start 1.7-3.3 mg/kg/day (theophylline base) in divided doses (e.g., every 8-12 hours), then titrate based on clinical response and serum theophylline concentrations.

Maintenance Dose

Adults: 400-600 mg/day in divided doses, adjusted to serum theophylline levels of 10-20 mcg/mL

Maximum Dose

Adults: Usual maximum 10 mg/kg/day (not to exceed 600 mg/day) with dose individualized to target serum theophylline concentrations (commonly 5-15 mcg/mL; avoid >20 mcg/mL).

Children's Dosage

For children 1-15 years (<45kg): Initially 12-14mg/kg/day, divided every 4-6 hours. Maximum dose is typically 20mg/kg/day or 600mg/day, whichever is less. Dose must be guided by serum levels.

Dose Adjustment Notes

Dose must be individualized using serum theophylline concentrations; reduce dose in hepatic impairment, heart failure, older adults, and during sustained high fever; increase dose may be needed in smokers; adjust with interacting drugs (CYP1A2/3A4 inhibitors/inducers).

How to Take

Oral use: shake well before each dose; measure with an oral syringe/medicine cup (not a kitchen spoon); may be taken with food or milk if stomach upset occurs; take doses at evenly spaced times each day as prescribed; do not switch brands/formulations without prescriber advice.

Side Effects

Common Side Effects

Common: nausea, vomiting, abdominal pain/heartburn, headache, insomnia, nervousness/restlessness, tremor, palpitations/tachycardia; may also cause diuresis and diarrhea.

Side Effect Frequency

Common dose-related GI/CNS stimulant effects (e.g., nausea/vomiting, headache, insomnia, tremor, palpitations); serious toxicity (e.g., seizures, ventricular arrhythmias) is associated with elevated serum concentrations, typically >20 mcg/mL.

Safety & Warnings

Contraindications

Contraindicated in patients with hypersensitivity to theophylline/other xanthines (e.g., aminophylline, caffeine) or any formulation component.

Warnings & Precautions

Key warnings/precautions: narrow therapeutic index-monitor serum theophylline concentrations and adjust for interacting drugs and smoking changes; use caution in seizure disorders, cardiac arrhythmias/ischemic heart disease, hyperthyroidism, peptic ulcer disease, hepatic impairment, and heart failure; febrile illness and age extremes can reduce clearance and increase toxicity risk.

Age Restriction

No absolute age restriction; may be used in pediatrics including infants only with specialist-directed weight-based dosing and therapeutic drug monitoring (TDM), with extra caution in neonates/infants due to reduced clearance and higher toxicity risk.

Drug Interactions

Drug Interactions

Major interactions: inhibitors that increase levels/toxicity (e.g., ciprofloxacin, macrolides such as erythromycin/clarithromycin, cimetidine, fluvoxamine; also allopurinol at higher doses) and inducers that decrease levels (e.g., rifampin, carbamazepine, phenytoin, phenobarbital) plus smoking (tobacco) decreases levels; stopping smoking can increase levels.

Interaction Severity

MAJOR (↑ levels/toxicity): ciprofloxacin, fluvoxamine, macrolides (erythromycin/clarithromycin), cimetidine; MAJOR (↓ levels/efficacy): rifampicin; MODERATE (↓ levels): carbamazepine, phenytoin, phenobarbital; MODERATE (pharmacodynamic): nonselective beta-blockers may reduce bronchodilation; MINOR/variable: caffeine (additive stimulation), oral contraceptives may modestly increase levels in some patients.

Food Interaction

May be taken with or without food; if GI upset occurs, take with food/milk; keep administration consistent relative to meals; avoid excessive caffeine and other xanthines; major diet pattern changes (e.g., high-protein/low-carb, charcoal-broiled foods) can increase clearance and may affect levels.

Special Populations

Children

For children 1-15 years (<45kg): Initially 12-14mg/kg/day, divided every 4-6 hours. Maximum dose is typically 20mg/kg/day or 600mg/day, whichever is less. Dose must be guided by serum levels.

Kidney Impairment

Generally no routine dose adjustment in renal impairment, but use caution and consider closer monitoring in severe renal failure due to possible metabolite accumulation and toxicity risk.

Storage & Patient Advice

Storage Conditions

Do not store above 30°C.

Missed Dose

Take the missed dose as soon as remembered unless it is close to the next scheduled dose; if close, skip the missed dose and resume the regular schedule-do not double doses.

Stopping the Medicine

Do not stop or change the dose without prescriber advice; taper is not routinely required, but symptoms may worsen if therapy is stopped and the regimen should be reassessed clinically.

Overdose

Overdose can cause severe/persistent vomiting, agitation/tremor, tachycardia, hypotension, ventricular arrhythmias, and seizures; it is a medical emergency requiring immediate hospital care, GI decontamination (activated charcoal when appropriate), continuous cardiac/neurologic monitoring, benzodiazepines for seizures, and consideration of extracorporeal removal (e.g., hemodialysis/hemoperfusion) in severe cases.

Patient Counseling

Take exactly as prescribed and do not change dose/brand without medical advice; shake well and measure doses accurately; take at evenly spaced times and keep timing consistent with meals; avoid excessive caffeine; report toxicity symptoms (persistent nausea/vomiting, severe headache, tremor, palpitations/fast heartbeat, insomnia, seizures); inform clinicians about all medicines (especially antibiotics like ciprofloxacin/macrolides) and any start/stop smoking or major diet changes; attend blood tests for theophylline levels; store below 30°C and keep out of reach of children.

Monitoring Requirements

Monitor serum theophylline concentration (typical target 10-20 mcg/mL for asthma; often 5-15 mcg/mL for COPD depending on local practice), clinical response (symptoms/PEF or spirometry), heart rate, and signs of toxicity; recheck levels with dose changes, illness/fever, smoking changes, or interacting drugs.

Pharmacology

Mechanism of Action

Bronchodilation primarily via nonselective phosphodiesterase inhibition (↑ cAMP) and adenosine receptor antagonism; also increases diaphragmatic contractility and stimulates respiratory drive.

Onset of Action

Immediate-release oral theophylline: onset typically about 30-60 minutes.

Duration of Effect

Immediate-release theophylline syrup: approximately 6-8 hours per dose (hence divided dosing).

Half-Life

Healthy non-smoking adults: ~5-8 hours (range commonly cited ~7-9 hours); shorter in children and smokers; longer in elderly and in hepatic impairment/heart failure (can be markedly prolonged, up to ~24 hours in severe cases).

Bioavailability

Approximately 100% (immediate-release oral syrup/solution).

Metabolism

Extensive hepatic metabolism primarily via CYP1A2, with contributions from CYP2E1 and CYP3A4 (demethylation/hydroxylation to mostly inactive metabolites).

Excretion

Renal - approximately 10% excreted unchanged in urine in adults; remainder as metabolites

Protein Binding

Approximately 40% protein bound (mainly to albumin; may be concentration-dependent).

Product Information

Available Dosage Forms

Syrup, immediate-release tablet, sustained-release tablet, sustained-release capsule, intravenous solution

Composition per Dose

Each 5 mL: Theophylline 60 mg (anhydrous)

Generic Availability

Yes

OTC Alternatives

No OTC alternative - prescription required for theophylline; salbutamol inhaler available OTC in some regions for acute bronchospasm

Symptom Target

Wheezing, Shortness of Breath, Chest Tightness

Sedating

No

Reviewed by Al Mujtama Pharmacy Medical Review Team. Last reviewed 19-08-2026