Adverse reactions with the use of LUFYLLIN (dyphylline) have been infrequent, relatively mild, and rarely required reduction in dosage or withdrawal of therapy.
The following adverse reactions which have been reported with other xanthine bronchodilators, and which have most often been related to excessive drug plasma levels, should be considered as potential adverse effects when dyphylline is administered:
Gastrointestinal: nausea, vomiting, epigastric pain, hematemesis, diarrhea.
Central nervous system: headache, irritability, restlessness, insomnia, hyperexcitability, agitation, muscle twitching, generalized clonic and tonic convulsions.
Cardiovascular: palpitation, tachycardia, extrasystoles, flushing, hypotension, circulatory failure, ventricular arrhythmias.
Renal: albuminuria, gross and microscopic hematuria, diuresis.
Other: hyperglycemia, inappropriate ADH syndrome.
Synergism between xanthine bronchodilators (e.g., theophylline), ephedrine, and other sympathomimetic bronchodilators has been reported. This should be considered whenever these agents are prescribed concomitantly.
Concurrent administration of dyphylline and probenecid, which competes for tubular secretion, has been shown to increase the plasma half-life of dyphylline (see Clinical PHARMACOLOGY ).