Adverse Reactions Theophylline causes numerous problems. Hypokalemia and rhabdomyolysis also occurs. The side-effects occurring within the usual therapeutic range include loss of appetite, nausea, vomiting, abdominal pain, tachycardia with subjectively experienced palpitations, extrasystoles, headaches, tremor, nervousness, excitability and sleep disturbances. A gastroesophageal reflux can be reinforced. Interactions Numerous interactions dependent on cytochrome P450.
Theophylline reduces the effect of lithium.