Theofast 300 CR Tablet

Methylxanthine bronchodilator for:

• Chronic asthma (add-on when inhalers are not enough)
• COPD and chronic bronchitis
• Apnoea of prematurity (specialist, as caffeine or theophylline)

Sustained-release tablets (adults): 200–300 mg every 12 hours, adjusted after 1–2 weeks according to response and blood levels (target 10–20 mg/L; many patients do well at 5–15).

Children (sustained release, over 6 years): about 9–10 mg/kg twice daily, adjusted by levels.

Syrup/immediate release: as prescribed, usually 3–4 times daily.

• Lower doses in elderly, heart failure, liver disease, and with interacting drugs.
• Smokers may need higher doses; stopping smoking can raise levels.
• Swallow SR tablets whole; do not switch brands without advice.

• Allergy to xanthines (theophylline, aminophylline, caffeine)
• Acute porphyria
• Uncontrolled heart rhythm disorders

Common (often dose-related): nausea, vomiting, stomach upset, headache, insomnia, nervousness, fast heartbeat, passing more urine.

At high levels: severe vomiting, irregular heartbeat, low potassium, seizures — can be fatal.

• Narrow safety margin — check blood levels when starting, after dose changes and when other drugs are added or stopped.
• Heart disease, high blood pressure, overactive thyroid, peptic ulcer, epilepsy, liver disease, fever, elderly: caution.
• Avoid large amounts of caffeine (tea, coffee, cola).

May be used in pregnancy when needed with level monitoring (clearance falls late in pregnancy). Passes into milk — may cause irritability in the baby; monitor.

Raise theophylline levels (toxicity): ciprofloxacin, erythromycin, clarithromycin, fluvoxamine, cimetidine, allopurinol (high dose), oral contraceptives, verapamil, fluconazole, stopping smoking.

Lower levels: smoking, rifampicin, carbamazepine, phenytoin, phenobarbital, St John's wort.

• Beta-blockers (oppose effect)
• Salbutamol, steroids, diuretics (low potassium)
• Doxophylline/aminophylline (do not combine)

Vomiting, agitation, fast or irregular heartbeat, low potassium, seizures. Medical emergency — activated charcoal and monitoring.

Store below 30°C, dry.