Effects of Piroxicam on Pharmacokinetics of Sulphadimidine in West African Dwarf Male and Female Goats (Capra hircus)

Sulphadimidine is used in the treatment of susceptible enteric bacteria that could cause enteritis and since piroxicam is a potent anti-inflammatory agent, it is co-administered with piroxicam intramuscularly. In view of this, effects of piroxicam on the pharmacokinetics of sulphadimidine were studied in West African Dwarf (WAD) goats. Twenty goats of both sexes, aged 1-year-old and weighing 10.4 ± 1.3 kg were divided into two groups of 10 each (5 males; 5 females) were administered 100 mg/kg body weight of sulphadimidine via right thigh muscle, whereas piroxicam (5 mg/kg) was administered to WAD goats (5 males; 5 females). Blood samples were collected over a range of time (0-192 hrs) and analyzed for presence of sulphadimidine. The results showed significant increase (p<0.05) in time maximum (Tmax=1.90 ± 0.45 hr), elimination half-life (T1/2β=9.13 ± 1.26 hr) and mean residence time (13.51 ± 1.90 hr) in male goats administered sulphadimidine/piroxicam as compared to Tmax (1.10 ± 0.29 hr), T1/2β (7.24 ± 0.59 hr) and MRT (10.54 ± 0.92 hr) of male goats administered sulphadimidine alone. However, WAD goats showed significant increase (P<0.05) in time maximum (Tmax=1.50 ± 0.22 hr), volume of distribution area (Vdarea=3.94 ± 0.55 L/kg), elimination half-life (T1/2β=8.72 ± 0.84 hr) and mean residence time (MRT=12.77 ± 1.90 hr) in female goats administered sulphadimidine with piroxicam as compared to Tmax (0.90 ± 0.18 hr), Vdarea (3.39 ± 0.38 l/kg), T1/2β (70.68 ± 0.72 hr) and MRT (11.25 ± 1.11 hr) of female goats administered sulphadimidine alone. Co-administration of piroxicam with sulphadimidine may delay elimination of sulphadimidine, prolong its therapeutic effect and withdrawal period in West African Dwarf goats.