Table 3

Effects of age, gender and drug treatment on theophylline pharmacokinetics

	Young Men (n = 8)	Young Women (n = 8)	Elderly Men (n = 8)	Elderly Women (n = 8)	P (Analysis of Variance)
	Young Men (n = 8)	Young Women (n = 8)	Elderly Men (n = 8)	Elderly Women (n = 8)	Age	Gender	Age × Gender
Clearance (ml/kg/hr)
Base line	50.8 ± 3.7	50.4 ± 4.5	40.5 ± 4.1	38.5 ± 2.6	.007	NS	NS
Cimetidine	38.9 ± 2.9	35.6 ± 2.9	29.7 ± 2.6	28.9 ± 1.1	.004	NS	NS
Ciprofloxacin	34.1 ± 2.3	33.6 ± 2.4	28.6 ± 2.4	27.5 ± 1.5	.014	NS	NS
Cimetidine + ciprofloxacin	31.0 ± 2.4	28.1 ± 1.5	24.7 ± 2.5	24.1 ± 1.0	.014	NS	NS
P (analysis of variance)	.001	.001	.001	.001
Half-life (hr)
Base line	7.1 ± 0.5	6.5 ± 0.5	9.5 ± 0.6	7.8 ± 0.6	.004	.047	NS
Cimetidine	10.0 ± 0.7	9.3 ± 0.7	12.4 ± 0.7	10.6 ± 0.3	.005	.045	NS
Ciprofloxacin	10.7 ± 0.7	9.6 ± 0.7	13.3 ± 0.5	11.3 ± 0.5	.002	.015	NS
Cimetidine + ciprofloxacin	12.3 ± 0.8	11.4 ± 0.5	15.6 ± 1.0	13.1 ± 0.2	.002	.019	NS
P (analysis of variance)	.001	.001	.001	.001
Volume of distribution at steady state (l/kg)
Base line	0.48 ± 0.03	0.43 ± 0.02	0.51 ± 0.03	0.40 ± 0.02	NS	.007	NS
Cimetidine	0.53 ± 0.04	0.45 ± 0.01	0.50 ± 0.03	0.43 ± 0.02	NS	.011	NS
Ciprofloxacin	0.49 ± 0.03	0.44 ± 0.02	0.53 ± 0.03	0.43 ± 0.02	NS	.006	NS
Cimetidine + ciprofloxacin	0.52 ± 0.03	0.44 ± 0.01	0.51 ± 0.03	0.43 ± 0.02	NS	.001	NS
P (analysis of variance)	.048	NS	NS	.032
Free fraction
Base line	0.54 ± 0.01	0.56 ± 0.01	0.60 ± 0.02	0.63 ± 0.01	.001	.104	NS
Cimetidine	0.54 ± 0.004	0.56 ± 0.01	0.59 ± 0.02	0.65 ± 0.02	.001	.005	.079
Ciprofloxacin	0.54 ± 0.01	0.56 ± 0.01	0.60 ± 0.01	0.62 ± 0.02	.001	.101	NS
Cimetidine + ciprofloxacin	0.54 ± 0.01	0.56 ± 0.01	0.59 ± 0.01	0.61 ± 0.02	.001	.090	NS
P (analysis of variance)	NS	NS	NS	.012

Values are mean ± S.E.