Insulin Isophane

What it is and how it works

Isophane (NPH) insulin is human insulin complexed with protamine, forming a suspension that is slowly absorbed after subcutaneous injection. Onset is about 1–2 hours with a duration of up to about 24 hours; insulin lowers blood glucose by promoting peripheral glucose uptake and inhibiting hepatic glucose production.

Indications

Treatment of diabetes mellitus requiring insulin, usually as basal insulin alone or combined with short-acting insulin or oral agents.

Dosage and administration (summary)

Subcutaneous injection once or twice daily; dose individualised according to blood glucose monitoring. Resuspend by gentle rolling and inversion before use; must not be given intravenously.

Contraindications

Hypoglycaemia; hypersensitivity to human insulin, protamine or excipients.

Warnings and precautions

Hypoglycaemia, including nocturnal hypoglycaemia, is the main risk. Rotate injection sites to avoid lipodystrophy and cutaneous amyloidosis; changes in insulin type require supervision. Combination with thiazolidinediones may cause fluid retention and heart failure.

Pregnancy

Insulin is the treatment of choice in pregnancy; requirements change through pregnancy and need close monitoring.

Storage and supply

Store unopened at 2–8 °C; do not freeze. In use, keep below 25–30 °C for up to 4–6 weeks according to the product; protect from light.

Source: reference summary prepared from the EU SmPC/EPAR, BNF and WHO Model Formulary. The approved product information in Iran governs.