Diazepam: routes of administration and rate of absorption. A study of women with pre-eclampsia.

Plasma diazepam concentrations were determined following oral, i.m. and i.v. administration to a group of pregnant women with pre-eclampsia and a group of normal pregnant women. Diazepam concentrations were greater following oral as compared with i.m. administration in the control group, who received a single 5-mg dose, and this confirms previous similar reports. In the patients with pre-eclampsia, who were pre-loaded with diazepam, the i.m. route provided much higher plasma diazepam concentrations than did the oral route. This was probably a result of reduced gastric motility and gastric secretion caused by diazepam which affected the absorption of subsequent diazepam administered orally, and it is unlikely that pre-eclampsia contributed to these differences. Mist. magnesium trisilicate seemed to improve the rate of absorption of diazepam from the intestine in five patients studied, although this effect is unlikely to have much clinical importance.