Important changes to nevirapine dosing advice made by FDA

Babies and children should receive doses of nevirapine (Viramune) according to their surface area rather than their weight, according to new prescribing advice issued by the US Food and Drug Administration (FDA). Other new prescribing advice includes a recommendation that the “lead-in” once daily dose period should not exceed 28 days, and firmer cautions about the use of nevirapine by patients with liver problems.

Paediatric nevirapine dose

The recommended oral dose of nevirapine for paediatric patients aged 15 days and older is 150mg/m² once daily for 14 days followed by 150mg/m² twice daily thereafter. However, the total daily dose of nevirapine should not exceed 400mg in any patient.

Although dosing nevirapine by weight and surface area are equally likely to result in therapy with adequate doses, dosing by body weight permits a smoother transition between age groups and is therefore preferred by the FDA.

Body surface area calculations for the use of the nevirapine oral suspension (50mg/5ml) are as follows:

• 0.06 to 0.12 m²: 1.25 ml
• 0.12 to 0.25 m²: 2.5 ml
• 0.25 to 0.42 m²: 5 ml
• 0.42 to 0.58 m²: 7.5 ml
• 0.58 to 0.75 m²: 10 ml
• 0.75 to 0.92 m²: 12.5 ml
• 0.92 to 1.08 m²: 15 ml
• 1.08 to 1.25 m²: 17.5 ml
• 1.25+ m²: 20 ml

Lead-in treatment

Treatment with nevirapine should be stopped by any patient who develops a severe rash, or any rash accompanied by constitutional symptoms. The FDA is also now advising that any patient who experiences a mild to moderate rash without constitutional symptoms during the 14-day lead-in period when therapy with the drug consists of 200mg per day (or 150mg/m² per day in paediatric patients) should not have their dose of nevirapine increased to the full therapeutic dose until their rash has gone.

Furthermore, the FDA is now advising that the total duration of the once daily lead-in period should not exceed 28 days. An alternative treatment should be sought if it appears necessary to extend the lead-in period beyond this point.

It was previously recommended that nevirapine should not be used by patients with severe liver impairment. The FDA has now extended this caution to include patients with moderate liver impairment.