Different diazepam rectal dosages

Q. Why is there a different rectal diazepam dose for those under 70 and those over 70 years of age?

A. To simplify the administration of medicines in the prehospital environment the JRCALC Clinical Practice Guidelines present doses of medicines by age rather than weight. This means that medicine doses need to be rounded up and down to ensure safe effective care. The sensitivity of patients to diazepam varies with age, and the recommended adult doses for rectal diazepam are:• Adults: 0.5mg/kg body weight• Elderly/debilitated: 0.25mg/kg body weight. The 2016 version of the JRCALC guidelines described a smaller dose and larger dose for the administration of rectal diazepam. This was intended to allow clinicians to make a judgement about a patient’s sensitivity to diazepam and reflects the rectal diazepam dose range recommended in the British National Formulary for convulsions:

• Adults: 10–20 mg, then 10–20 mg after 10–15 minutes if required

• Elderly/debilitated: 10 mg, then 10 mg after 10–15 minutes if required.

The JRCALC description of a smaller and larger diazepam dose caused confusion and so in the last guideline update the doses were simplified. This included reducing the dose for the over 70’s, which is an arbitrary age used to describe the elderly. There is not a dose reduction for the intravenous diazepam preparation. The usual initial intravenous dose for adults is 0.15-0.25mg/kg, and this is usually halved in elderly and debilitated patients. The JRCALC does take account of this, as patients who do not respond to the first diazepam dose (about 0.15mg/kg) will receive a second dose.

As the guidelines evolve the JRCALC are considering other descriptors which can be used to enable clinicians to make appropriate dose adjustments for defined groups of patients, such as the frail and debilitated. The priority is to write a clear guideline.