Ensure correct brand is used as there are different formulations with different bioavailabilities. Complex interactions. Always check with existing drugs.
About:-Methylxanthine Bronchodilator.Action:▪Competitive nonselective phosphodiesterase inhibitor▪Raises intracellular cAMP, activates PKA.▪Inhibits TNF alpha and leukotriene synthesis▪Adenosine antagonist.Indications:▪Acute Bronchospasm - Asthma and COPD.▪Pulmonary oedemaInteractions :- check BNF as this list is not complete▪Metabolised by liver p450 system.▪Smokers, Chronic alcohol, Liver inducers reduce drugs levels. Need increased dose for same effects.▪Liver failure, heart failure, elderly, fluvoxamine, cimetidine, macrolides (erythromycin/clarithromycin)/ketoconoazole, fluconazole increase drug levels.▪Increased Seizures with Quinolones.Cautions:▪Cardiac disease as may increase arrhythmias.▪Epilepsy, Hyperthyroidism.▪Fever, Porphyria, Diabetes Mellitus.Contraindications:▪Allergy.▪Acute porphyria.Side effects:▪Arrhythmias, Palpitations.▪Seizures, Delirium/Confusion, Insomnia, Restlessness.▪Nausea, vomitingDose:▪Aminophylline Oral : 225-450 mg bd for non smokers▪Aminophylline Oral : 350-700 mg bd for smokers▪Aminophylline IV : load 5 mg/kg (250-500 mg) and then 0.5 mg/kg/hour IVI▪Maintain plasma levels at 10-20 mg/l (55-110 micromole/l)
Reference:Drive
PJ Mehta's Practical Medicine Principles and Practice of Pharmaceutical Medicine Second Edition Edited by Lionel D. Edwards .