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Intermediate-acting insulin

Isophane (NPH) insulin

Brand names: Insulatard, Humulin I, Insuman Basal

Isophane (NPH) insulin is an intermediate-acting human insulin suspension used as basal insulin in type 1 and type 2 diabetes.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

Clinical monograph

How it works

It stimulates insulin receptors to enhance glucose uptake and suppress hepatic glucose output; combination with protamine delays subcutaneous absorption, producing an intermediate duration of action with a recognisable peak.

Prescribing in practice

  • Hypoglycaemia, especially nocturnal, is the main hazard owing to the suspension's peaked action profile.
  • Resuspend the cloudy preparation by gentle rolling before each dose to ensure consistent delivery, and rotate injection sites.
  • Where mixed with short-acting insulin, follow the correct drawing-up sequence and product instructions to avoid contamination or dosing error.

Monitoring

Monitor capillary blood glucose, including pre-breakfast levels, alongside HbA1c to titrate the dose safely.

Counselling the patient

  • Mix the cloudy insulin gently until uniformly milky before injecting.
  • Be alert to night-time hypoglycaemia and keep fast-acting sugar available.
  • Rotate injection sites and do not share insulin devices.

Evidence & guidelines

Isophane insulin is a long-established basal insulin within UK diabetes management.

Reference: NICE NG17/NG28; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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