Mirabegron Allergy Profile
True allergic reactions to mirabegron (Myrbetriq) are uncommon, and when they occur, the most common allergic symptom is urticaria (hives). 1
Prevalence of Allergic Reactions
- Allergic reactions to mirabegron are rare compared to other drug classes such as platinum-based chemotherapy agents or certain antibiotics. 2
- The FDA drug label documents specific allergic-type reactions occurring in less than 1% of patients treated with mirabegron in clinical trials. 1
- In large-scale clinical trials involving 2,736 patients receiving mirabegron for 12 weeks, true allergic/hypersensitivity reactions were infrequent adverse events. 1
Most Common Allergic Symptoms
When allergic reactions do occur with mirabegron, the documented allergic-type manifestations include:
- Urticaria (hives) - the most commonly documented allergic-type skin reaction 2, 1
- Rash and pruritus (itching) 2, 1
- Lip edema 2, 1
- Leukocytoclastic vasculitis - a more serious but rare allergic reaction 2, 1
- Purpura 2, 1
Important Clinical Distinction
It is critical to distinguish true allergic reactions from common adverse effects, which are NOT allergic in nature:
- The most frequently reported adverse reactions to mirabegron are hypertension (7.5-11.3%), nasopharyngitis (3.5-3.9%), urinary tract infections (2.9-4.2%), and headache (2.1-3.2%) - these are pharmacologic effects, not allergic reactions. 2, 1
- These common adverse effects occur at rates only slightly higher than placebo and do not represent drug allergy. 1
Angioedema Risk
- Angioedema is a rare but serious potential allergic reaction that can involve the tongue, hypopharynx, or larynx. 1
- If angioedema involving the tongue, hypopharynx, or larynx occurs, immediately discontinue mirabegron and provide appropriate therapy to ensure a patent airway. 1
- This represents a true medical emergency requiring prompt intervention. 1
Clinical Context
- Real-world pharmacovigilance data from 18,763 adverse event reports identified unexpected reactions including lip swelling and swollen tongue, which may represent allergic phenomena. 3
- Mirabegron has a substantially lower allergic reaction profile compared to medications like carboplatin (which causes allergic reactions in 16% of patients) or fluoroquinolone antibiotics. 4, 2
- The overall tolerability profile of mirabegron is favorable, with most patients experiencing no allergic reactions whatsoever. 5, 6