Pharmacodynamic evaluation of intragastric pH and implications for famotidine dosing in the prophylaxis of non-steroidal anti-inflammatory drug induced gastropathy—a proof of concept analysis

Figures & data

Figure 1. Mean pH values on Day 1.

Figure 2. Mean pH values on Day 5.

Table 1. Trough famotidine concentrations.

	Trough plasma concentration of famotidine (ng/mL)
	40 mg BID		26.6 mg TID
	Day 1	Day 5	Day 1	Day 5
Mean	10.5	15.7	9.7	15.7
SD	2.8	4.6	4.9	8.9

Figure 3. Mean observed vs fitted plasma famotidine concentrations single oral doses of 40 mg famotidine (Pepcid) (n = 30) (top) and ibuprofen 800 mg/famotidine 26.6 mg (n = 35) (bottom).

Figure 4. Predicted plasma concentration-time profiles of famotidine.

Table 2. Pharmacokinetic parameters of different famotidine formulations.

Parameter	Famotidine^a	Ibuprofen/famotidine combination^b
V/F (L)	240	234
ka (h^−1)	0.795	1.81
ke (h^−1)	0.267	0.195
tlag (h)	0.344	0.504

^a40 mg famotidine, p.o.

^b800 mg Ibuprofen/26.6 mg famotidine, p.o.

Figure 5. Predicted intragastric pH-time profiles of famotidine following a 5-min intravenous infusion of 0.5 mg/min famotidine.

Table 3. Pharmacodynamic parameters for famotidine.

Parameter
Emax	7.11
EC50 (ng/mL)	30.60
E0	2.13
Γ	9.88

Figure 6. Predicted intragastric pH-time profiles of famotidine.