The actual dose delivery from a diazepam enema differs depending on the patients position during administration

In a randomized single-blind cross-over study on 14 volunteers the relation between dose, effect and serum concentration was studied when diazepam in solution was administered in a dose of 0.5 mg/kg bodyweight rectally with the volunteer placed either laterally or prone. When lying prone the delivered diazepam dose was on average 24% higher compared to in the lateral position. The difference in delivered dose affected sedation as well as serum concentration but did not prolong recovery time. At the time of clinical recovery, the serum concentration was still at a very high level. Oxygen (p02) and carbon dioxide (pCO2) tensions were monitored transcutaneously in 9 subjects and were unaffected by the sedative level. The study suggests that when diazepam enemas similar to the ones used here, they should be administered with the patient in a prone position.