CGRP Receptor Monoclonal Antibody — Migraine Prevention Pregnancy: There are a limited amount of data from use in pregnant women; animal studies do not indicate direct or indirect harmful effects with respect to reproductive toxicity, but as a precautionary measure it is preferable to avoid use during pregnancy. It is unknown whether erenumab is excreted in human milk — a risk to the breast-fed infant cannot be excluded during the first few days after birth, after which use during breast-feeding could be considered only if clinically needed. Animal studies showed no impact on female or male fertility (eMC §4.6).

Erenumab

Brand names: Aimovig

Erenumab is a human monoclonal antibody given by subcutaneous injection for the prophylaxis of migraine in adults with frequent attacks.

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: 70 mg every 4 weeks; some patients may benefit from 140 mg every 4 weeks

Route: Subcutaneous — injected into the abdomen, thigh or the outer area of the upper arm (the arm should only be used if the injection is given by someone other than the patient); rotate injection sites and do not inject into skin that is tender, bruised, red or hard

Frequency: Every 4 weeks

eMC §4.2 (Aimovig 140 mg solution for injection in pre-filled pen). Treatment should be initiated by physicians experienced in the diagnosis and treatment of migraine and is intended for patients with at least 4 migraine days per month when initiating erenumab. Each 140 mg dose is given either as one subcutaneous injection of 140 mg or as two subcutaneous injections of 70 mg. Clinical studies have demonstrated that the majority of patients responding to therapy showed clinical benefit within 3 months; consideration should be given to discontinuing treatment in patients who have shown no response after 3 months, and the need to continue treatment should be evaluated regularly thereafter. Aimovig is intended for patient self-administration after proper training, or may be given by another appropriately instructed individual; the entire contents of the pre-filled pen should be injected and each pen is single-use. ELDERLY (65 years and over): not studied, but no dose adjustment is required as the pharmacokinetics of erenumab are not affected by age. HEPATIC IMPAIRMENT: no dose adjustment is necessary in mild to moderate hepatic impairment. PAEDIATRIC: safety and efficacy in children below 18 years of age have not yet been established and no data are available — verify any under-18 use against a children's formulary. US LABELLING (cross-check): the same 70 mg once monthly dosage with an option of 140 mg once monthly; if a dose is missed, administer as soon as possible and then schedule monthly from the date of the last dose.

Dose adjustments

Renal

No dose adjustment is necessary in patients with mild to moderate renal impairment (eMC §4.2).

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; 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

Hypersensitivity to the active substance or to any of the excipients (eMC §4.3). The US labelling states the product is contraindicated in patients with serious hypersensitivity to erenumab or to any of the excipients, reactions having included anaphylaxis and angioedema.

Side effects

Injection site reactions (common; 5.6% at 70 mg and 4.5% at 140 mg) — mostly mild and transient, most frequently localised pain, erythema and pruritus, with injection site pain typically subsiding within 1 hour
Constipation (common; 1.3% at 70 mg and 3.2% at 140 mg) — the US labelling additionally warns of constipation with serious complications
Muscle spasms (common; 0.1% at 70 mg and 2.0% at 140 mg)
Pruritus (common; 0.7% at 70 mg and 1.8% at 140 mg); alopecia and rash (frequency not known)
Hypersensitivity reactions including anaphylaxis, angioedema, rash, swelling/oedema and urticaria (common); oral sores including stomatitis, mouth ulceration and oral mucosal blistering (frequency not known). The US labelling also lists hypertension and Raynaud's phenomenon as labelled warnings.

Clinical monograph

How it works

It blocks the calcitonin gene-related peptide (CGRP) receptor, preventing CGRP-mediated vasodilation and pain signalling implicated in migraine.

Prescribing in practice

Hypersensitivity reactions including rash, angioedema and anaphylaxis have been reported and constipation can be severe, occasionally requiring further intervention.
It is recommended for patients with frequent migraine in whom previous preventive treatments have failed, consistent with NICE criteria.
Assess response after an adequate period and discontinue if migraine frequency is not meaningfully reduced.

Monitoring

No routine blood monitoring is needed, but headache frequency should be reviewed and patients asked about constipation and blood-pressure changes.

Counselling the patient

This is a preventive injection to reduce migraine frequency, not a treatment for an acute attack.
Report severe or persistent constipation, and tell us about any rash or swelling.
You can be taught to give the injection yourself using the prefilled device.

Evidence & guidelines

NICE recommends erenumab for migraine prophylaxis in defined circumstances, supported by randomised trials showing reduced monthly migraine days versus placebo.

Reference: NICE NG218 (Migraine); ARISE Trial; STRIVE Trial (NEJM 2017); 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

Pathways