Long-acting growth hormone analogue Pregnancy: No available data on use during pregnancy; published studies of short-acting recombinant growth hormone over several decades have not identified a drug-associated risk of major birth defects, miscarriage or adverse maternal or fetal outcomes. Animal studies were not teratogenic at approximately 12 times the clinical exposure at the maximum recommended human dose of 8 mg/week.

Somapacitan

Brand names: Sogroya

Somapacitan is a long-acting recombinant human growth hormone derivative administered once weekly for the treatment of growth hormone deficiency.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: Adults with growth hormone deficiency (GHD): initiate at 1.5 mg once weekly (both for treatment-naive patients and for patients switching from daily growth hormone); increase the weekly dosage every 2 to 4 weeks by approximately 0.5 mg to 1.5 mg until the desired response is achieved

Route: Subcutaneous injection into the upper arms, thigh, abdomen or buttocks, with weekly rotation of the injection site to avoid lipohypertrophy/lipoatrophy

Frequency: Once weekly, at any time of day

Max: 8 mg once weekly (adult GHD)

US label (Sogroya, somapacitan-beco) — no UK SPC was fetched. Titrate the dosage based on clinical response and serum IGF-1 concentrations; draw IGF-1 samples 3 to 4 days after the prior dose. Decrease the dosage as necessary on the basis of adverse reactions and/or serum IGF-1 concentrations above the age- and sex-specific normal range. Patients aged 65 years and older: initiate at 1 mg once weekly and use smaller dose increments when titrating. Perform a fundoscopic examination before initiating treatment to exclude pre-existing papilledema; if papilledema is identified, evaluate the aetiology and treat the underlying cause before initiating. Treatment should be supervised by a healthcare provider experienced in the diagnosis and management of growth hormone deficiency. Available as three prefilled pens: 5 mg/1.5 mL (delivery range 0.025 to 2 mg, 0.025 mg increments), 10 mg/1.5 mL (0.05 to 4 mg, 0.05 mg increments) and 15 mg/1.5 mL (0.1 to 8 mg, 0.1 mg increments). Patients switching from daily human growth hormone should choose the preferred day for the weekly dose and take the final daily dose the day before (or at least 8 hours before) the first weekly dose.

Paediatric dose

Dose: 0.16 mg/kg

Route: Subcutaneous injection (upper arms, thigh, abdomen or buttocks, rotating sites)

Frequency: Once weekly

US label: growth hormone deficiency in paediatric patients — 0.16 mg/kg based on actual body weight once weekly, for treatment-naive patients and patients switching from daily growth hormone (somatropin). Short stature born small for gestational age (SGA), Noonan syndrome (NS) and idiopathic short stature (ISS) — 0.24 mg/kg based on actual body weight once weekly. Individualise the dosage for each patient based on the growth response. Safety and effectiveness established in paediatric patients 2.5 years of age and older. Assess compliance and evaluate other causes of poor growth (hypothyroidism, undernutrition, advanced bone age, antibodies to recombinant human growth hormone) if height velocity fails to increase, particularly during the first year. Patients treated in childhood whose epiphyses are closed should be re-evaluated before continuing. Contraindicated in paediatric patients with closed epiphyses. No maximum paediatric dose is stated in the label. Verify against a children's formulary before use.

Dose auto-extracted from US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Paediatric weight-based calculator

Patient weight (kg)

Verify in a children's formulary

Contraindications

Acute critical illness after open-heart surgery, abdominal surgery or multiple accidental trauma, or acute respiratory failure (risk of increased mortality)
Hypersensitivity to somapacitan-beco or any of its excipients
Paediatric patients with closed epiphyses
Active malignancy
Active proliferative or severe non-proliferative diabetic retinopathy
Paediatric patients with Prader-Willi syndrome who are severely obese, have a history of upper airway obstruction or sleep apnoea, or have severe respiratory impairment (risk of sudden death)

Side effects

Injection site reaction
Headache
Nasopharyngitis and respiratory tract infection
Pyrexia
Vomiting and diarrhoea
Cough, ear infection, pain in extremity (these are the common reactions reported in paediatric patients; the adult adverse reaction list was truncated in the source)

Interactions

Replacement glucocorticoid treatment — growth hormone inhibits 11-beta-hydroxysteroid dehydrogenase type 1, reducing serum cortisol; patients on glucocorticoid replacement for hypoadrenalism may require an increase in maintenance or stress doses (cortisone acetate and prednisone may be affected more than others)
Cytochrome P450-metabolised drugs — growth hormone treatment increases CYP450-mediated antipyrine clearance and may alter the clearance of compounds metabolised by CYP450 liver enzymes

Clinical monograph

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.

Reference: NICE; SmPC; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

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