Usage
Erenumab is prescribed for the prevention of migraine in adults who experience at least 4 migraine days per month. It is classified as a monoclonal antibody and specifically as a CGRP receptor antagonist. It works by blocking the calcitonin gene-related peptide (CGRP) receptor, which plays a crucial role in the pathophysiology of migraine.
Alternate Names
Erenumab is also known by the brand name Aimovig.
How It Works
Pharmacodynamics: Erenumab specifically targets and binds to the CGRP receptor, preventing CGRP from binding and exerting its vasodilatory and pro-inflammatory effects. This, in turn, helps prevent the initiation and propagation of migraine attacks.
Pharmacokinetics: Erenumab is administered subcutaneously. The absorption is slow, reaching peak serum concentrations in about 5 to 7 days. It has a half-life of approximately 28 days. Erenumab is primarily eliminated via non-renal clearance mechanisms, meaning it is not extensively metabolized by the kidneys or liver. As a monoclonal antibody, it’s expected to be catabolized into small peptides and amino acids.
Mode of Action: Erenumab acts by competitively inhibiting the binding of CGRP to its receptor. By blocking the receptor, Erenumab diminishes the downstream effects of CGRP, preventing vasodilation and neurogenic inflammation associated with migraine.
Elimination Pathways: Erenumab is not primarily cleared through renal or hepatic pathways. It is degraded through catabolism like other immunoglobulin G (IgG) antibodies, breaking down into small peptides and amino acids throughout the body. It is not metabolized by CYP enzymes.
Dosage
Standard Dosage
Adults:
The recommended starting dose of Erenumab is 70 mg subcutaneously once every 4 weeks. Some patients may benefit from a higher dose of 140 mg administered subcutaneously once every 4 weeks, either as a single 140 mg injection or two 70 mg injections. The injection sites (abdomen, thigh, or outer area of the upper arm) should be rotated.
Children:
The safety and efficacy of Erenumab have not been established in children under 18 years of age, therefore, it is not recommended for pediatric use.
Special Cases:
- Elderly Patients: No dose adjustment is necessary for elderly patients.
- Patients with Renal Impairment: No dose adjustment is necessary for patients with mild to moderate renal impairment.
- Patients with Hepatic Dysfunction: No dose adjustment is necessary for patients with mild to moderate hepatic impairment.
- Patients with Comorbid Conditions: Patients with certain major cardiovascular diseases were excluded from clinical trials; therefore, limited safety information is available for these patient groups. Monitoring for hypertension is important, as both the development and worsening of pre-existing hypertension have been reported.
Clinical Use Cases
Erenumab is specifically indicated for migraine prevention. It is not indicated for the treatment of acute migraine attacks. It has no indicated use in settings like intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations.
Dosage Adjustments
No dose adjustment is recommended for elderly patients or those with mild to moderate hepatic or renal impairment.
Side Effects
Common Side Effects
- Injection site reactions (pain, redness, itching, swelling)
- Constipation
- Muscle cramps or spasms
Rare but Serious Side Effects
- Serious hypersensitivity reactions (rash, angioedema, anaphylaxis)
Long-Term Effects
No specific long-term adverse effects have been consistently identified.
Adverse Drug Reactions (ADR)
- Hypersensitivity reactions require immediate medical attention.
Contraindications
- Hypersensitivity to erenumab or any of its excipients
Drug Interactions
No clinically significant drug interactions have been identified.
Pregnancy and Breastfeeding
- Pregnancy: There is limited data on erenumab use during pregnancy. Animal studies did not show harm to the fetus, however, it is generally recommended to avoid its use during pregnancy unless the potential benefit clearly outweighs the potential risk.
- Breastfeeding: It is unknown whether erenumab is excreted in human milk. Limited data suggests minimal risk to the breastfed infant, but caution is advised. The decision to discontinue breastfeeding or erenumab should be individualized based on the mother’s clinical need and the potential benefits and risks to the infant.
Drug Profile Summary
- Mechanism of Action: CGRP receptor antagonist.
- Side Effects: Injection site reactions, constipation, muscle cramps, rarely hypersensitivity.
- Contraindications: Hypersensitivity to erenumab.
- Drug Interactions: No significant drug interactions.
- Pregnancy & Breastfeeding: Limited data, use with caution.
- Dosage: 70 mg or 140 mg subcutaneously once monthly.
- Monitoring Parameters: Blood pressure (due to potential for hypertension).
Popular Combinations
Erenumab is not typically used in combination with other CGRP monoclonal antibodies.
Precautions
- Pre-screening for hypersensitivity is essential.
- Monitor blood pressure.
- Counsel patients about potential injection site reactions.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Erenumab?
A: The recommended starting dose is 70 mg subcutaneously every 4 weeks. Some patients may benefit from 140 mg monthly.
Q2: How is Erenumab administered?
A: Erenumab is administered via subcutaneous injection.
Q3: Can Erenumab be used during pregnancy?
A: Erenumab should be used during pregnancy only if the potential benefit outweighs the potential risk. Consult with a specialist.
Q4: Can Erenumab be used during breastfeeding?
A: Caution is advised. The decision should be individualized considering the mother’s clinical need and the infant’s potential exposure.
Q5: Are there any drug interactions with Erenumab?
A: No clinically significant drug interactions have been reported.
Q6: What are the common side effects of Erenumab?
A: The most common side effects are injection site reactions, constipation, and muscle cramps.
Q7: How does Erenumab work?
A: It is a monoclonal antibody that blocks the CGRP receptor, preventing CGRP’s effects in migraine.
Q8: Who should not take Erenumab?
A: Patients with a known hypersensitivity to erenumab should not take it.
Q9: How long does it take for Erenumab to work?
A: Many patients experience benefit within 3 months, but individual responses may vary.
Q10: What should I do if I miss a dose of Erenumab?
A: Administer the missed dose as soon as possible. Resume the regular monthly schedule from the date of the last dose.
