What is the recommended rectal diazepam dose (mg/kg) for children and adults, including maximum single and daily doses and repeat dosing interval?

Rectal Diazepam Dosing

For seizure management when IV access is unavailable, administer rectal diazepam at 0.5 mg/kg up to a maximum of 20 mg per dose. 1

Pediatric Dosing

• Children: 0.5 mg/kg rectally, maximum 20 mg per dose 1
• Age-based dosing (alternative): 0.2-0.5 mg/kg depending on age 2
• Repeat dosing: May administer a second dose 4 hours after the first dose in children 2
• Maximum daily doses: Children received up to 2 doses within 12 hours in clinical trials 2

Adult Dosing

• Adults: 0.5 mg/kg rectally, maximum 20 mg per dose 1
• Repeat dosing: Adults may receive three doses total—one at onset, then additional doses at 4 and 12 hours after onset 2
• Maximum daily doses: Adults received up to 3 doses within 24 hours in clinical trials 2

Clinical Pharmacokinetics

• Time to peak concentration: Rectal diazepam solution reaches maximum concentration (Tmax) within 5-20 minutes in children 3
• Absorption variability: Peak serum concentrations following rectal administration can occur between 10-120 minutes in adults, with absorption being more erratic compared to IV administration 1, 4
• Therapeutic levels: Serum diazepam levels above 400 ng/mL are suggested for satisfactory anticonvulsant effect, though this may take over 2 hours to achieve with 10-20 mg rectal doses 5

Important Clinical Considerations

Formulation Matters

• Use diazepam solution or gel formulations for rectal administration—these have superior absorption compared to suppositories 4
• Rectal diazepam gel demonstrated superiority over placebo in reducing seizure frequency in both children (p<0.001) and adults (p=0.02) 2

Safety Monitoring

• Respiratory monitoring is essential: Monitor oxygen saturation and be prepared to provide respiratory support, particularly when diazepam is combined with other sedative agents 1
• Somnolence is the most frequent adverse effect; respiratory depression was not reported in major clinical trials 2
• Paradoxical agitation may occur, especially in younger children 1

Critical Timing Issue

• Follow immediately with a long-acting anticonvulsant due to diazepam's rapid redistribution and potential for seizure recurrence within 15-20 minutes 1
• Time to first seizure recurrence after initial treatment was significantly longer with diazepam compared to placebo (p<0.001) 2

Reversal Agent Caution

• Flumazenil may reverse life-threatening respiratory depression caused by diazepam, but it also counteracts anticonvulsant effects and may precipitate seizure recurrence 1

Administration Technique

• Rectal diazepam gel can be administered at home by trained caregivers and is effective and well-tolerated for acute repetitive seizures 2
• The rectal route is preferred when IV access is not practical or possible for emergency seizure management 3