Table 3

CYP3A inducers and their therapeutic dosage in humans

Drug	Example of Clinical Use	Dosage/Day	Maximum M Dosage/Day	Fold Maximum Dose versus Maximum Dexamethasone Dose
Rifampicin	Staphylococcal infections	0.6–1.2 g/day, oral	1.5 mmol	60
	Tuberculosis	2–4 divided doses
Dexamethasone	Anti-inflammatory, Diagnosis of Cushing's disease	0.5–10 mg/day, oral	25 μmol	1
Spironolactone	Edema and ascites in cirrhosis of the liver	100–200 mg/day, oral	480 μmol	19
	Congestive heart failure
Cyproterone acetate	Male hypersexuality	200–30 mg/day, oral	720 μmol	29
	Prostate cancer	2–3 divided doses
Metyrapone	Diagnosis and treatment of Cushing's disease	0.25–6 g/day, oral	27 mmol	1080
		6 divided doses

Data taken from the British National Formulary 37 (March 1999), published by the British Medical Association.