For the treatment of acute severe asthma, theophylline is less effective than inhaled or injected B2-selective agonists.

Bronchodilator effect by: phosphodiesterase inhibition, intracellular calcium modulation and prostaglandin antagonism.

Maintenance therapy with theophylline is effective in reducing the frequency and severity of the symptoms of chronic asthma. It may be similar in effectiveness to cromolyn or B-2 agonists. It is generally used along with low dose steroids or Cromolyn sodium.

Sustained release preparations allow for effective control of nocturnal symptoms.

Dose varies with age and other factors, begin dose at 10 mg/kg per day in two divided doses. Final dosage is usually based on the peak serum concentration measurement obtained at steady state.

Patients with mild chronic asthma may be controlled at steady-state theophylline serum concentrations less than 10 ug/ml; patients with more severe disease may require concentrations greater than 10 ug/ml for effective control of symptoms.

The rate of theophylline metabolism varies greatly among patients and is influenced by numerous medical conditions and other drugs. The rate of theophylline metabolism is reduced, leading to increased serum levels, in such conditions as cardiac decompensation, respiratory failure, hepatic cirrhosis, sustained high fever, viral infections, hypothyroidism, and after administration of cimetidine, oral contraceptives, erythromycin, ciprofloxacin, and disulfiram. In contrast, factors such as cigarette or marijuana smoking, hyperthyroidism, rifampin, phenytoin, carbamazepine, and phenobarbital increase the rate of metabolism.

Oral slow-release formulations provide stable serum concentrations and increases patient compliance. However, the rate and extent of absorption vary between formulations, between individuals, and possibly in the same individual from time to time. Food ingestion may also affect the rate of absorption in different ways depending on the specific formulation.

Do not -

1) Increase the dose if it is already at lower end of range
2) Maintain any dose that is not tolerated
3) Allow generic substitution