What is the treatment for a rash caused by metoprolol (beta blocker)?

Treatment for Metoprolol-Induced Rash

Discontinue metoprolol immediately and switch to an alternative antihypertensive agent that does not cross-react with beta-blockers. 1, 2

Immediate Management Strategy

Discontinuation Protocol

• Stop metoprolol as soon as drug-induced rash is suspected, as continued exposure can lead to progression from mild rash to severe autoimmune blistering disorders like pemphigus foliaceus or pemphigus vulgaris 1, 2
• Do not attempt rechallenge with metoprolol, as this can trigger recurrence of the rash and potentially more severe reactions 1, 2
• Taper metoprolol gradually (reduce by 25-50% every 1-2 weeks) rather than abrupt cessation to avoid rebound hypertension, worsening angina, or cardiac events 3, 4

Symptomatic Treatment Based on Severity

For Grade 1 rash (affecting <10% body surface area):

• Apply topical emollients to affected areas 5
• Use mild-strength topical corticosteroids (e.g., hydrocortisone 2.5%) once daily 5
• Add oral antihistamines (loratadine 10 mg daily for daytime, or diphenhydramine 25-50 mg at night if pruritus interferes with sleep) 5

For Grade 2 rash (10-30% body surface area):

• Apply moderate-to-high potency topical corticosteroids (mometasone furoate 0.1% or betamethasone valerate 0.1%) once to twice daily 5
• Continue oral antihistamines for pruritus control 5
• Consider dermatology referral and skin biopsy to rule out pemphigus or other severe cutaneous reactions 5, 1

For Grade 3 rash (>30% body surface area or Grade 2 with substantial symptoms):

• Initiate systemic corticosteroids: prednisolone 0.5-1 mg/kg daily for 3 days, then taper over 1-2 weeks for mild-to-moderate cases 5
• For severe cases, use IV methylprednisolone 0.5-1 mg/kg and convert to oral steroids upon response, tapering over 2-4 weeks 5
• Obtain urgent dermatology consultation 5
• Perform punch biopsy and clinical photography to document severity and guide treatment 5

For Grade 4 rash (skin sloughing >30% body surface area with systemic symptoms):

• Administer IV methylprednisolone 1-2 mg/kg immediately 5
• Hospitalize patient under dermatology supervision 5
• Monitor for secondary infections, as blistering wounds are susceptible to life-threatening complications 1

Alternative Antihypertensive Selection

Preferred Alternatives That Avoid Beta-Blocker Cross-Reactivity

First-line alternatives:

• ACE inhibitors (e.g., lisinopril, enalapril) for non-Black patients without contraindications 3
• Angiotensin receptor blockers (ARBs) (e.g., candesartan) for patients intolerant to ACE inhibitors 5
• Calcium channel blockers (e.g., amlodipine 5-10 mg daily, diltiazem 120-360 mg daily) - these do not cause bradycardia and are safe alternatives 3

If beta-blockade is absolutely required (e.g., for post-MI, heart failure, or rate control):

• Consider bisoprolol as an alternative second-generation beta-blocker, which has been successfully used in patients with propranolol hypersensitivity 6
• However, cross-reactivity between beta-blockers for cutaneous reactions is possible, so close monitoring is essential 7
• Start at the lowest possible dose and monitor closely for recurrence of rash 3

Monitoring and Follow-Up

• Reassess skin lesions after 2 weeks of treatment 5
• If rash worsens or does not improve with topical therapy, escalate to systemic corticosteroids 5
• Monitor blood pressure and heart rate closely during metoprolol taper and after switching to alternative agents 3
• Document complete resolution of rash before considering any beta-blocker rechallenge (though rechallenge is generally not recommended) 1, 2

Critical Warnings

Do not underestimate metoprolol-induced rash - while rare, it can progress to severe autoimmune blistering disorders like pemphigus foliaceus or pemphigus vulgaris, which carry significant morbidity 1, 2

Pemphigus-like reactions may not resolve immediately after metoprolol discontinuation and may require prolonged immunosuppressive therapy 2

Secondary infections are the primary cause of mortality in severe blistering reactions, requiring vigilant monitoring and early antibiotic intervention if signs of infection develop 1