<prompt> Which of the following agent increases blood levels of theophylline?ErythromycinRifampicinTobaccoEthanol  <response>: Factors Affecting Clearance of Theophylline: Increased clearance: Enzyme induction mainly CYP1A2 by co-administered drugs e.g., rifampicin, barbiturates, ethanol Smoking tobacco, marijuana CYP1A2 induction High-protein, low-carbohydrate diet Barbecued meat Childhood Decreased clearance: CYP inhibition cimetidine, erythromycin, ciprofloxacin, allopurinol, fluvoxamine, zileuton, zafirlukast Congestive hea failure Liver disease Pneumonia Viral infection and vaccination High-carbohydrate diet Old age 