Theophylline + Etofylline Extended Release

Indications

Theophylline + Etofylline Extended Release is used for: Chronic Asthma

Adult Dose

Oral Chronic bronchospasm Adult: 300-1,000 mg in divided doses 12 hrly. Elderly: Lower doses should be used. Hepatic impairment: Reduce dose.

Child Dose

Oral Chronic bronchospasm Child: <6 yr Not recommended; 6-12 yr 20-35 kg: 75-150 mg bid; >12 yr 150-300 mg bid.

Renal Dose

Administration

May be taken with or without food. May be taken w/ meals to reduce GI discomfort. Some individual prep must be taken w/ meals or on an empty stomach

Contra Indications

Hypersensitivity to theophylline and other xanthine derivatives. Porphyria.

Precautions

Patient w/ peptic ulceration, hyperthyroidism, DM, glaucoma, severe hypoxemia, epilepsy, HTN, heart failure, cardiac arrhythmias or other CV disease, acute febrile illness, COPD, cor pulmonale; smokers. Hepatic or renal impairment. Elderly and childn. Pregnancy and lactation. Monitoring Parameters Monitor heart rate, CNS effects, resp rate, arterial or capillary blood gases, theophylline levels.

Pregnancy-Lactation

Interactions

Increased plasma concentrations w/ allopurinol, some antiarrhythmics, cimetidine, disulfiram, fluvoxamine, interferon alfa, macrolide antibiotics, quinolones, OCs, tiabendazole, viloxazine, Ca channel blockers. Reduced plasma concentrations w/ phenytoin and other antiepileptics, ritonavir, rifampicin, sulfinpyrazone, aminoglutethimide, barbiturates, carbamazepine. Enhanced lithium excretion. May potentiate hypokalaemia w/ corticosteroids and diuretics. Risk of synergistic toxicity when given w/ halothane or ketamine. May antagonise effects of adenosine and competitive neuromuscular blockers. Increased bronchospasm w/ β-blockers.

Adverse Effects

Side effects of Theophylline + Etofylline Extended Release : Nausea, vomiting, epigastric pain, abdominal cramps, anorexia, diarrhoea, haematemesis; headache, irritability, restlessness, nervousness, insomnia, dizziness, reflex hyperexcitability, seizures; palpitations, sinus tachycardia, extrasystoles, increased pulse rate, flushing, circulatory failure, hypotension, ventricular arrhythmias; transient increase in urinary frequency, dehydration, twitching of fingers and hands, tachypnoea, elevated serum AST concentrations. Potentially Fatal: Convulsions, cardiac arrhythmias, severe hypotension or cardiac arrest.

Mechanism of Action

Theophylline competitively blocks phosphodiesterase which increases cyclic adenine monophosphate (cAMP) tissue concentrations causing bronchodilatation, diuresis, CNS and cardiac stimulation, and gastric acid secretion.