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.