TABLE 2

The influence of old age in humans on the metabolism of drugs and other compounds that undergo phase I, phase II, capacity-limited and flow-limited metabolism

Hepatic Metabolism	Reduced	Percentage of Change	Unchanged	Percentage of Change
Flow-limited	Indocyanine green	−35^, −60^
	Pethidine	−44^*, +12
	Morphine	−18^, −35^, −16
	Propranolol	−51, −41^, −30^, −24^*
	Amitriptyline	−62^*, −14
	Verapamil	−32^*, −42
	Imipramine	−45^*
	Lignocaine	+7, −35^*, −6
Capacity-limited	Theophylline	−22^, −33^, −15, +33, +17, −15, nonsmoker −35^, −33^, +11, −31^*	Diazepam	−3, male −39^, −48^, female −6, −17
	Antipyrine	−20^, −42^, +32, −39^, −52^, −51^, +32, −33^	Digitoxin	+20
			Phenytoin	+62^*, +4
			Salicylic acid	−7, +4, −29
			Valproic acid	0, −16, 0
			Warfarin	+25, −25, 0
Phase I	Antipyrine	−20^, −42^, +32, −39^, −52^, −51^, +32, −33^	Warfarin	−25, −25, 0
	Chlormethiazole	−84^, −30^	Caffeine	+13
	Diltiazem	−7, −39^*	Phenytoin	+62^*, +4
	Propranolol	−51, −41^, −30^, −24^*
	Theophylline	−22^, −33^, −15, +33, +17, −15, nonsmoker −35^, −33^, +11, −31^*
	Imipramine	−45^*
	Amitriptyline	−62^*, −14
	Verapamil	−32^*, −42
	Ibuprofen	−16^*, +12
	Lignocaine	+7, −35^*, −6
Phase II	Morphine	−18^, −35^, −16	Isoniazid	rapid acetylator + 13, −13 slow acetylator −1, −22
			Oxazepam	+20
			Paracetamol	−35^, −21, −25^, −34^, −23, −19^, −8
			Salicylic acid	−7, +4, −29
			Temazepam	male −1, female −12

↵* Statistically significant; −, decrease; +, increase (Le Couteur and McLean, 1998).