teofyllin

Theophylline, also known as teofyllin in some languages, is a methylxanthine drug used as a bronchodilator in the management of asthma and chronic obstructive pulmonary disease (COPD). It is a nonselective phosphodiesterase inhibitor and an antagonist of adenosine receptors, leading to increased intracellular cAMP in smooth muscle and anti-inflammatory effects.

The drug can be administered orally or by intravenous infusion. It is rapidly absorbed with variable bioavailability and is extensively metabolized in the liver, primarily by cytochrome P450 1A2. The elimination half-life varies with age, smoking status, liver function, and concomitant illnesses, ranging from about 3 to 12 hours in adults; it is shorter in smokers and longer in infants and those with liver disease.

Clinically, theophylline is less commonly used as a frontline bronchodilator today due to a narrow therapeutic window and potential adverse effects, but it may be considered when inhaled therapies are insufficient or in specific settings. Dosing is individualized and requires therapeutic drug monitoring. Target trough levels commonly lie between 5 and 15 micrograms per milliliter; levels above ~20 µg/mL increase the risk of toxicity.

Adverse effects are dose-related and can include nausea, vomiting, restlessness, tachycardia, palpitations, arrhythmias, and seizures. Toxicity is more likely with interactions that raise theophylline levels or decrease clearance, such as certain antibiotics (erythromycin, ciprofloxacin), age, liver disease, or concurrent caffeine use.

Contraindications include active peptic ulcers and seizure disorders. Theophylline’s use has declined in many countries but remains an option in select patients or resource-limited settings.