Systemic drugs for obstructive respiratory diseases. Xanthines. Theophylline
Theophylline is a bronchodilator of the methylxanthine group. The mechanism of action is mainly based on blocking adenosine receptors, inhibition of phosphodiesterases, an increase in intracellular cAMP, a reduction in intracellular concentration of calcium ions, resulting in relaxation of the smooth muscles of the bronchi, gastrointestinal tract, bile ducts, uterus, coronary, cerebral and pulmonary blood vessels. Peripheral vascular resistance decreases, tone of the respiratory muscles (intercostal muscles and diaphragm) increases, pulmonary vascular resistance drops and blood oxygenation improves.
– Bronchial asthma.
– Chronic obstructive pulmonary disease (chronic obstructive bronchitis, pulmonary emphysema).
– Pulmonary hypertension.
– Central sleep apnea syndrome.
Take orally 30-60 minutes before meals or 2 hours after meals, with a sufficient amount of liquid. The 300 mg tablet can be split in half (100 mg tablets are not splittable) but cannot be ground, chewed or dissolved in water. In some cases, to reduce irritant effects on the gastric mucosa, the drug may be taken during or immediately after meals.
The dosage regimen is selected individually, depending on the patient's age, body weight, and metabolic characteristics.
The initial daily dose for adults and children aged from 12 years with a body weight of over45 kg is 300 mg (one 300 mg tablet once per day or 3 100 mg tablets once per day). After 3 days of administration, increase the daily dose to 450 mg (1½ 300 mg tablet), after 3 more days of treatment, the daily dose can be increased to 600 mg (one 300 mg tablet twice per day or 3 100 mg tablets twice per day) if required.
Increasing the dose is only possible in good tolerability.