erenumab

Action and Spectrum

Mechanism of action 

erenumab is a monoclonal antibody that is used to treat migraines. It targets and blocks the action of calcitonin gene-related peptide (CGRP), a chemical involved in developing migraines. CGRP is a neurotransmitter released in response to inflammation and other stimuli, and it is thought to play a role in transmitting pain signals in the brain. By blocking the action of CGRP, erenumab helps reduce migraines’ frequency and severity. 

Spectrum 

erenumab is a specific type of monoclonal antibody called a humanized monoclonal antibody, which means that it is derived from a human antibody but has some portions derived from a mouse antibody. This allows it to be more specific in targeting CGRP and reduces the risk of an immune response to the drug. 

Drug Interaction

Adverse Reaction

Frequency defined:  

1-10% 

Constipation 

Muscle spasms 

Cramps 

Pain at the site injection 

Post-marketing reports 

Oral mucosal ulceration 

Anaphylaxis 

Rash 

Hypersensitivity 

Hypertension 

Angioedema 

Black Box Warning

Contraindication / Caution

Contraindications 

erenumab is contraindicated in patients with hypersensitivity to erenumab or its excipients. It is also contraindicated in patients with hypersensitivity reactions to other monoclonal antibodies. 

Caution 

• erenumab is a monoclonal antibody, and like other monoclonal antibodies, it may increase the risk of infection. The patient should tell their healthcare provider if they have an active infection or have a history of recurrent infections. 
• erenumab may cause injection site reactions, such as redness, swelling, and pain. The patient should tell their healthcare provider if they experience any injection site reactions that are severe or persistent. 
• erenumab may cause constipation. The patient should drink plenty of fluids and eat a high-fiber diet to help prevent constipation. 
• erenumab may interact with other medications that the patient is taking. It is important for the patient to inform their healthcare provider about all medications they are taking, including prescription and over-the-counter medications, as well as any supplements or herbal products. 

Pregnancy / Lactation

Pregnancy consideration: Insufficient data available 

Lactation: Excretion of the drug in human breast milk is unknown 

Pregnancy category: 

Category A: well-controlled and Satisfactory studies show no risk to the fetus in the first or later trimester.   

Category B: there was no evidence of risk to the fetus in animal studies, and there were not enough studies on pregnant women. 

Category C: there was evidence of risk of adverse effects in animal reproduction studies, and no adequate evidence in human studies must take care of potential risks in pregnant women.    

Category D: adequate data available with sufficient evidence of human fetal risk from various platforms, but despite the potential risk, and used only in emergency cases for potential benefits.    

Category X: Drugs listed in this category outweigh the risks over benefits. Hence these categories of drugs need to be avoided by pregnant women.    

Category N: There is no data available for the drug under this category 

Pharmacology

Pharmacology 

erenumab is a monoclonal antibody that is used to prevent migraines. It works by targeting and blocking the action of calcitonin gene-related peptide (CGRP), a molecule that is involved in the development of migraines. By blocking CGRP, erenumab can help to prevent migraines from occurring.  

erenumab is administered as a subcutaneous injection. It is typically given once a month, and the dosage may be adjusted based on the individual’s response to treatment. Erenumab is effective in reducing the frequency and severity of migraines in clinical studies. It is generally well tolerated, with the most common side effects being injection site reactions and constipation. 

Pharmacodynamics 

As a monoclonal antibody, erenumab targets and blocks the action of calcitonin gene-related peptide (CGRP), a molecule involved in migraines’ development. By blocking CGRP, erenumab can help to prevent migraines from occurring. 

erenumab is administered as a subcutaneous injection. It is generally well tolerated, with the most common side effects being injection site reactions and constipation. 

Pharmacokinetics 

Absorption 

• Absolute bioavailability: the absolute bioavailability of erenumab is 82%, which means that 82% of the medication is absorbed into the bloodstream after it is administered. 
• Peak plasma time: the peak plasma time of erenumab is approximately six days, which means that it takes about six days for the concentration of the medication in the blood to reach its highest level. 
• Peak plasma concentration: the peak plasma concentration of erenumab is 6.1 mcg/mL when the medication is given at a dose of 70 mg and 15.8 mcg/mL when the medication is given at a dose of 140 mg. The peak plasma concentration is the highest concentration of the medication in the blood. 
• AUC: the area under the concentration-time curve (AUC) measures the total exposure to the medication over a given period. The AUC of erenumab is 159 day ·mcg/mL when the medication is given at a dose of 70 mg and 505 day·mcg/mL when the medication is given at a dose of 140 mg. 
• Bioavailability: The bioavailability of erenumab is 82%. 

Distribution 

The volume of distribution is 3.86 L. This means that, on average, 3.86 litres of body fluid is required to contain the amount of erenumab present in the body 

Metabolism 

erenumab is metabolized in the liver and eliminated primarily through the feces. It is not metabolized by the cytochrome P450 (CYP450) enzyme system and is not expected to interact with drugs metabolized by CYP450 enzymes. 

Elimination/excretion 

The drug has two elimination phases: one that occurs at low concentrations and is predominantly through saturable binding to a target (CGRP receptor), and one that occurs at higher concentrations and is mainly through a nonspecific, nonsaturable proteolytic pathway. 

Adminstartion

Administration 

Sub cutaneous administration 

The medication is available in injection form and is intended for subcutaneous (SC) use only, meaning it should be injected into the fatty tissue under the skin. It is important to note that the needle shield within the prefilled autoinjector and the cap of the prefilled syringe contain dry natural rubber, which is a derivative of latex and may cause allergic reactions in individuals who are sensitive to latex. 

The medication is intended for self-administration, so it is essential to properly train on the preparation and administration of the injection, including proper aseptic technique. Before administering the injection, it is essential to allow the syringe or autoinjector to sit at room temperature for at least 30 minutes, protected from direct sunlight. The solution should not be warmed using a heat source (such as hot water or microwave) or shaken. The solution should also be visually inspected for particulate matter and discoloration, and it should not be used if it is cloudy, discolored, or contains particles. 

The injection should be administered in the abdomen, thigh, or upper arm, avoiding areas where the skin is tender, bruised, red, or hard. The prefilled autoinjector and syringe are single-dose and deliver the entire contents. If a dose is missed, it should be administered as soon as possible, and the monthly dose should be rescheduled from the date of the last dose. 

Storage 

This medication is used to prevent migraines in adults. It is essential to refrigerate the medication at a temperature of 2-8ºC (36-46ºF) in the original carton to protect it from light. If the medication is removed from the refrigerator, it can be stored at room temperature (up to 25ºC [77ºF]) in the original carton for up to 7 days. However, it should be discarded if left at room temperature for more than seven days. The medication should not be frozen and should not be shaken. 

Patient Information Leaflet

Patient information leaflet 

Generic Name: erenumab 

Pronounced: [ e-REN-ue-mab ] 

Why do we use erenumab? 

erenumab is a prescription medication used to prevent migraines in adults.