What is the recommended dose of rectal diazepam (Diazepam) for an adult seizure?

Rectal Diazepam Dosing for Adult Seizures

The recommended dose of rectal diazepam for an adult seizure is 0.2-0.5 mg/kg (typically 10-20 mg) administered as a single dose, which may be repeated in 4-12 hours if needed. 1

Dosing Guidelines

Standard Adult Dosing

• Initial dose: 0.2-0.5 mg/kg (typically 10-20 mg for average adults)
• Maximum single dose: 20 mg for most adults
• Timing of effect: Peak serum concentrations typically achieved within 10-60 minutes 2
• Duration of action: Effective for several hours, with significant reduction in seizure activity

Repeat Dosing Protocol

• May repeat dose after 4 hours if seizures recur 3
• Adults may receive up to three doses in a 24-hour period (at 0,4, and 12 hours) 3
• Do not exceed recommended dosing frequency due to risk of cumulative sedation

Administration Technique

1. Position patient on their side (recovery position)
2. Remove protective cap from applicator
3. Insert applicator tip into rectum (2-5 cm)
4. Push plunger to deliver medication
5. Hold buttocks together for 10 seconds after administration to prevent leakage
6. Monitor patient for seizure cessation and potential side effects

Clinical Efficacy

Rectal diazepam has demonstrated significant efficacy in terminating seizures:

• Produces highly significant reduction in seizure frequency compared to placebo 2, 3
• Effect is most marked 10-20 minutes after administration 2
• Significantly extends time to first recurrence of seizures after initial treatment 3
• Onset of effect typically noted approximately 10 minutes after injection 4

Monitoring and Safety Considerations

Common Side Effects

• Somnolence/sedation (most common, occurring in approximately 25% of patients) 5
• Note that post-ictal sedation may be difficult to distinguish from medication-induced sedation

Important Safety Points

• Respiratory depression is rare with rectal administration compared to IV diazepam 5
• No reports of respiratory depression in major clinical trials 3, 5
• Monitor respiratory status, especially in patients receiving other CNS depressants
• Overdosages of up to 330% of maximum recommended dose have been reported without respiratory or cardiac depression 5

Special Considerations

• Rectal diazepam can be administered by trained caregivers in out-of-hospital settings 3, 5
• Particularly useful when IV access is not available or practical 1
• Low potential for abuse compared to other routes of administration 5
• Avoid chronic administration as it may lead to tachyphylaxis 5

When to Consider Alternative Treatments

• If seizures continue despite rectal diazepam administration, emergency medical services should be contacted immediately
• For status epilepticus refractory to benzodiazepines, second-line agents such as valproate (20-30 mg/kg IV), phenytoin/fosphenytoin (18-20 mg/kg IV), or levetiracetam (30-60 mg/kg IV) should be considered in the hospital setting 6

Rectal diazepam is an effective, well-tolerated treatment for acute seizures in adults when administered at the appropriate dose, with the advantage of being administrable outside of hospital settings by trained caregivers.