Complete adverse effect profile including incidence rates and management
Important Safety Information
This is not a complete list of all possible side effects. Contact your healthcare provider if you experience any unexpected symptoms. For serious or life-threatening side effects, seek emergency medical attention immediately.
Nausea (up to 10–15% of patients, reduced by taking with food)
Headache (6–10%)
Flatulence and bloating (5–8%)
Diarrhea (3–7%)
Brown or dark yellow discoloration of urine (very common, harmless)
Vomiting (3–6%)
Dizziness or drowsiness (2–5%)
Loss of appetite (anorexia) (2–5%)
Abdominal pain or stomach upset (3–5%)
Mild skin rash (1–3%)
Itching (pruritus) (1–3%)
Muscle aches (myalgia) (1–2%)
Transient mild elevations in liver enzymes (1–2%)
Pulmonary reactions — acute hypersensitivity pneumonitis (fever, chills, cough, dyspnea, eosinophilia) occurring within first week of therapy; subacute or chronic pulmonary fibrosis with prolonged use requiring immediate discontinuation
Hepatotoxicity — hepatic necrosis, hepatitis, and cholestatic jaundice, including rare fatal cases; monitor liver function with prolonged therapy
Peripheral neuropathy — severe, irreversible sensorimotor polyneuropathy reported especially in patients with renal impairment, anemia, diabetes, electrolyte imbalance, or vitamin B deficiency; discontinue if signs of peripheral neuropathy develop
Hemolytic anemia — associated with G6PD deficiency; screen at-risk patients before initiating therapy; contraindicated in G6PD deficiency
Severe hypersensitivity reactions — anaphylaxis, angioedema, urticaria, lupus-like syndrome, and drug reaction with eosinophilia and systemic symptoms (DRESS)
Clostridioides difficile-associated diarrhea (CDAD) and pseudomembranous colitis — can occur during or weeks after therapy; evaluate any patient presenting with diarrhea post-treatment
Optic neuritis — rare but serious visual disturbance requiring immediate discontinuation
Severe skin reactions — Stevens-Johnson syndrome and toxic epidermal necrolysis (very rare)
Exfoliative dermatitis and erythema multiforme
Sialadenitis (parotid gland swelling)
Pancreatitis
Crystalluria (rare with adequate hydration)
Megaloblastic anemia (particularly with folate deficiency)
Intracranial hypertension (pseudotumor cerebri) — rare, particularly in pediatric patients
Alopecia (hair loss) — reversible upon discontinuation
Like all medications, Macrobid can cause side effects. However, not everyone who takes this medication will experience them. Many side effects are dose-dependent and may improve as your body adjusts to the medication. Others may require dose adjustment or medical attention.
Contact your healthcare provider promptly if you experience:
Seek immediate emergency medical care if you experience signs of: