Somapacitan

How it works

It is a growth hormone analogue with reversible albumin binding that prolongs its half-life, allowing weekly dosing while activating growth hormone receptors to stimulate growth and metabolic effects, partly via IGF-1.

Prescribing in practice

• Growth hormone therapy can reduce insulin sensitivity and unmask or worsen glucose intolerance, so glucose status should be monitored, particularly in those at risk of diabetes.
• It is contraindicated in active malignancy, and growth hormone should not be used where there is evidence of active tumour activity.
• Replacement may reveal underlying hypoadrenalism and can reduce thyroxine levels, so other pituitary hormone axes should be assessed and managed.

Monitoring

Monitor IGF-1 to guide dosing, along with glucose status and thyroid and adrenal function as clinically indicated.

Counselling the patient

• Administer the injection on the same day each week and rotate injection sites.
• Report increased thirst or urination, which may indicate raised blood sugar.
• Mention symptoms such as fatigue that might reflect other hormone deficiencies needing adjustment.

Evidence & guidelines

Once-weekly somapacitan is supported by the SPC and clinical trials demonstrating efficacy in growth hormone deficiency.