Allergic Reactions to Furosemide: Prevalence and Clinical Manifestations
Allergic reactions to furosemide are rare, with severe hypersensitivity reactions occurring in a very small percentage of patients despite its widespread use. According to the FDA drug label, allergic reactions can range from mild skin manifestations to severe anaphylactic reactions, though the latter are uncommon 1.
Prevalence of Furosemide Allergies
- The prevalence of allergic reactions to furosemide is extremely low
- As of 2013, only 49 cases of furosemide allergy had been documented in medical literature 2
- In a 2018 study examining patients with sulfonamide allergies who received furosemide during nuclear diuretic renography, only 2 out of 83 patients (2.4%) developed minor rash reactions, with no serious reactions reported 3
- In a large clinical toxicity study of 2,367 hospitalized patients receiving furosemide, adverse reactions occurred in 10.1% of patients, but most were related to the drug's pharmacological effects (electrolyte disturbances, volume depletion) rather than allergic reactions 4
Types of Allergic Reactions to Furosemide
According to the FDA drug label 1, allergic reactions to furosemide can manifest as:
Systemic Hypersensitivity Reactions
- Severe anaphylactic or anaphylactoid reactions (with shock) - very rare
- Systemic vasculitis
- Interstitial nephritis
- Necrotizing angiitis
Dermatologic-Hypersensitivity Reactions
- Severe cutaneous adverse reactions:
- Toxic epidermal necrolysis
- Stevens-Johnson Syndrome
- Erythema multiforme
- Drug rash with eosinophilia and systemic symptoms (DRESS)
- Acute generalized exanthematous pustulosis
- More common skin reactions:
- Exfoliative dermatitis
- Bullous pemphigoid
- Purpura
- Photosensitivity
- Rash
- Pruritus
- Urticaria
Case Reports of Allergic Reactions
- Anaphylaxis: A case report documented a 24-year-old woman who experienced oral itching, generalized urticaria, facial angioedema, dyspnea, and hypotension within 10 minutes of taking furosemide 40mg 5
- Delayed hypersensitivity: A case report described a patient who developed a delayed, erythematous and pruritic skin eruption after furosemide ingestion, confirmed by a positive lymphocyte transformation test 2
Cross-Reactivity Considerations
- Patients allergic to sulfonamides may also be allergic to furosemide tablets 1
- However, the 2022 drug allergy practice parameter update notes that there is minimal concern for cross-reactivity between sulfonamide antimicrobials and non-antimicrobial sulfonamides like furosemide 6
- Furosemide is listed in a table of "Drugs with no or weak evidence of cross-reactivity in patients with a history of a sulfonamide antimicrobial adverse reaction" 6
Management of Furosemide Allergy
- For patients with confirmed furosemide allergy who require loop diuretics, desensitization protocols have been successfully used 7
- Alternative loop diuretics may be considered, though cross-reactivity is possible
- For patients with sulfonamide antimicrobial allergies, furosemide can generally be safely administered as cross-reactivity is minimal 6, 3
Monitoring and Prevention
- Patients receiving furosemide should be observed for signs of allergic reactions, particularly during initial administration
- For patients with a history of allergic reactions to medications, particularly sulfonamides, closer monitoring may be warranted during initial furosemide administration
In conclusion, while allergic reactions to furosemide can occur and range from mild to severe, they are relatively rare considering the widespread use of this medication. The most common manifestations are dermatologic reactions, with anaphylaxis being extremely uncommon.