Cephalexin Adverse Effects (Keflex)
Cephalexin commonly causes gastrointestinal adverse reactions. [1] Serious reactions include hypersensitivity reactions and severe cutaneous adverse reactions. [1]
Common Side Effects
- Diarrhea [1]
- Nausea [1]
- Vomiting [1]
- Dyspepsia [1]
- Abdominal pain [1]
Hypersensitivity Reactions
- Rash [1]
- Urticaria [1]
- Angioedema [1]
- Anaphylaxis [1]
- Erythema multiforme [1]
- Stevens-Johnson syndrome [1]
- Toxic epidermal necrolysis [1]
Genitourinary and Mucocutaneous Effects
- Genital pruritus [1]
- Vaginitis [1]
- Vaginal discharge [1]
- Genital candidiasis [1]
Neuropsychiatric and Musculoskeletal Effects
- Dizziness [1]
- Fatigue [1]
- Headache [1]
- Agitation [1]
- Confusion [1]
- Hallucinations [1]
- Arthralgia [1]
- Arthritis and joint disorder [1]
Less Common/Other Reported Laboratory and Drug-Class Effects
- Blood dyscrasias have been reported with cephalosporins, including thrombocytopenia and neutropenia [2]
- Eosinophilia and other altered laboratory findings have been reported [2]
When to Seek Urgent Care
Urgent evaluation is indicated for features of severe allergy such as anaphylaxis, angioedema, or severe skin reactions such as Stevens-Johnson syndrome or toxic epidermal necrolysis. [1]
Medication Effects That Can Affect Testing
- Cephalexin may cause a false-positive result for glucose in urine testing. [1]