Anti-CGRP monoclonal antibody Pregnancy: There are no adequate data on the developmental risk associated with use in pregnant women. Administration to rats and rabbits during organogenesis, or to rats throughout pregnancy and lactation, at plasma exposures greater than expected clinically did not result in adverse effects on development. A pregnancy exposure registry monitors outcomes in women exposed during pregnancy.

Galcanezumab

Brand names: Emgality

Galcanezumab is a humanised monoclonal antibody given by subcutaneous injection for the prophylaxis of migraine, and is also used for episodic cluster headache.

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: Migraine: 240 mg loading dose (two consecutive subcutaneous injections of 120 mg each) once, followed by 120 mg monthly

Route: Subcutaneous injection only — administer in the abdomen, thigh, back of the upper arm or buttocks; do not inject into areas where the skin is tender, bruised, red or hard

Frequency: Single 240 mg loading dose, then 120 mg once monthly

EPISODIC CLUSTER HEADACHE: the recommended dosage is 300 mg (three consecutive subcutaneous injections of 100 mg each) at the onset of the cluster period, and then monthly until the end of the cluster period. MISSED DOSE (migraine): administer as soon as possible, then schedule monthly from the date of the last dose. MISSED DOSE (cluster period): administer as soon as possible, then schedule monthly from the date of the last dose until the end of the cluster period. ADMINISTRATION: intended for patient self-administration after proper training on the single-dose prefilled pen or prefilled syringe, using aseptic technique; protect from direct sunlight; allow to sit at room temperature for 30 minutes before injection; do not warm with a heat source; do not shake; inspect visually and do not use if cloudy or if visible particles are present. Both the prefilled pen and prefilled syringe are single-dose and deliver the entire contents. PAEDIATRIC: safety and effectiveness in paediatric patients have not been established. ELDERLY: clinical studies did not include sufficient numbers of patients aged 65 and over to determine whether they respond differently. SOURCE: no UK SPC was fetched in this bundle — this draft is distilled from the US EMGALITY prescribing information and must be verified against the UK SPC.

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.

Contraindications

Serious hypersensitivity to galcanezumab or to any of the excipients

Side effects

Injection site reactions — the most common adverse reactions (incidence >=2% and at least 2% greater than placebo)
Hypersensitivity reactions including dyspnoea, urticaria and rash; cases of anaphylaxis and angioedema reported post-marketing (reactions can occur days after administration and may be prolonged)
Constipation with serious complications (post-marketing, reported with monoclonal antibody CGRP antagonists)
Hypertension — new-onset or worsening of pre-existing hypertension
Raynaud's phenomenon — new-onset or worsening of pre-existing Raynaud's phenomenon

Clinical monograph

How it works

It binds to calcitonin gene-related peptide (CGRP) ligand, preventing it from activating its receptor and reducing the neurovascular signalling involved in migraine and cluster headache.

Prescribing in practice

Hypersensitivity reactions including rash, pruritus and, rarely, anaphylaxis can occur, sometimes days after administration, so counsel patients to report these.
For migraine prophylaxis it is recommended where previous preventive treatments have failed, in line with NICE guidance.
Review effectiveness after an adequate treatment period and stop if there is no worthwhile reduction in attack frequency.

Monitoring

No routine laboratory monitoring is required, but attack frequency should be tracked and patients observed for hypersensitivity reactions.

Counselling the patient

This is a preventive injection to reduce attack frequency, not a treatment for an acute attack.
Report any rash, swelling or breathing difficulty, which can occur even some days after the injection.
You can be taught to give the injection yourself with the prefilled device.

Evidence & guidelines

NICE recommends galcanezumab for migraine prophylaxis in defined circumstances, and randomised trials support its efficacy in migraine and episodic cluster headache.

Reference: NICE TA659/TA764; 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.

Calculators

Drugs

Fremanezumab · Anti-CGRP monoclonal antibody

Pathways