Green A W, Ebling W F, Gardner M J, Jusko W J
Am J Med. 1984 Dec;77(6):1115-8. doi: 10.1016/0002-9343(84)90199-2.
The pharmacokinetics of theophylline and methylprednisolone were examined before and during cimetidine treatment in an asthmatic woman who required long-term administration of these drugs. Cimetidine reduced theophylline plasma clearance by 30 percent, and measurement of urinary metabolites showed that 3-methylxanthine formation was inhibited more strongly than that of the methylated uric acid metabolites. Assessment of methylprednisolone disposition following oral and intravenous doses revealed no effect of cimetidine on the bioavailability (74 to 81 percent absorption) or plasma clearance (22 to 24 liters per hour) of the steroid. Thus, cimetidine exhibits variable and selective effects on the biotransformation pathways of drugs important in asthma therapy.
在一名需要长期服用这些药物的哮喘女性患者中，研究了西咪替丁治疗前和治疗期间茶碱和甲泼尼龙的药代动力学。西咪替丁使茶碱的血浆清除率降低了30%，尿代谢产物测定表明，3-甲基黄嘌呤的形成比甲基化尿酸代谢产物的形成受到更强的抑制。口服和静脉给药后对甲泼尼龙处置的评估显示，西咪替丁对该类固醇的生物利用度（吸收74%至81%）或血浆清除率（每小时22至24升）没有影响。因此，西咪替丁对哮喘治疗中重要药物的生物转化途径表现出可变的选择性作用。
