Intermediate-acting insulins

Intermediate-acting insulin, also called NPH, starts working in one to two hours, peaks in four to twelve hours, and lasts up to about 18 hours. It provides background insulin coverage and is often given once or twice a day. NPH is cloudy and is gently rolled to mix it before a dose is drawn up. Its pronounced peak raises the risk of low blood sugar in the afternoon or overnight.

• Insulin NPH (isophane)Known brand names include Humulin N.