Adults

Typical oral dose for Aminophylline is 100-300 mg every 6-8 hours, adjusted based on plasma concentrations and clinical response. For Amynil 1 mg tablet, specific physician guidance is crucial as this strength is unusually low for standard systemic bronchodilation.

Elderly

Lower doses may be required due to decreased clearance and increased sensitivity to adverse effects. Careful monitoring and dose titration are necessary, especially with this specific 1 mg tablet.

Renal_impairment

Dose adjustment is generally not required for renal impairment as aminophylline is primarily metabolized hepatically, but caution is advised in severe cases. Specific guidance for the 1 mg tablet should be sought from a healthcare professional.

Onset

Oral: Bronchodilator effect usually starts within 30-60 minutes.

Excretion

Excreted renally, with approximately 10% as unchanged drug and the remainder as metabolites. Renal clearance is faster in children.

Half life

The plasma half-life varies significantly, typically ranging from 6-12 hours in adults but can be shorter in smokers and longer in patients with liver disease or heart failure.

Absorption

Aminophylline is rapidly and completely absorbed after oral administration. Peak plasma concentrations are usually reached within 1-2 hours.

Metabolism

Primarily metabolized in the liver by the cytochrome P450 enzyme system, mainly CYP1A2, into inactive metabolites and a minor active metabolite (theophylline).

Beta-agonists, Corticosteroids

May have additive bronchodilator effects and potentially increased side effects.

Phenobarbital, Phenytoin, Rifampicin

These drugs can induce aminophylline metabolism, leading to decreased plasma levels and reduced efficacy.

Cimetidine, Erythromycin, Ciprofloxacin, Oral Contraceptives

These drugs can inhibit aminophylline metabolism, leading to increased plasma levels and potential toxicity.