Antiarrhythmic agents ■ Disopyramide Worsening LV dysfunction,
anticholinergic (avoid in prostatic hypertrophy, glaucoma, myasthenia gravis)
■ Flecainide Arrhythmia risk in structural heart disease (avoid in heart failure or post myocardial infarction)
■ Lidocaine/ Seizures, CNS depression mexiletine
■ Procainamide Torsades de pointes, hypotension (IV), lupus-like syndrome with long-term therapy
■ Propafenone Bronchospasm, arrhythmia risk in structural heart disease
■ Quinidine Anticholinergic effects (prostatic hypertrophy, glaucoma,
Fig. 4. A drug, given as a solid, encounters several barriers and sites of loss in its sequential movement during gastrointestinal absorption. Dissolution, a prerequisite to movement across the gut wall, is the first step. Incomplete dissolution or metabolism in the gut lumen or by enzymes in the gut wall is a cause of poor absorption. Removal of drug as it first passes through the liver further reduces absorption.