Isoniazid induced gynaecomastia: a case report

Area of Science:

• Endocrinology
• Pharmacology
• Pulmonology

Background:

• Anti-tubercular chemotherapy is essential for treating tuberculosis.
• Gynaecomastia is an uncommon adverse effect of certain medications.
• Isoniazid is a first-line anti-tuberculosis drug with a known, though rare, association with endocrine disturbances.

Observation:

• A 60-year-old male patient with pulmonary tuberculosis developed painful bilateral gynaecomastia after five months of standard anti-tubercular treatment (ATT).
• The patient was receiving rifampicin, isoniazid, ethambutol, and pyrazinamide initially, followed by rifampicin, isoniazid, and ethambutol.
• The gynaecomastia emerged while on the rifampicin, isoniazid, and ethambutol regimen.

Findings:

• Discontinuation of isoniazid led to a reduction in breast swelling and tenderness.
• The patient experienced partial resolution of gynaecomastia after stopping isoniazid.
• Six months post-treatment, the patient remained asymptomatic with only slight, non-tender bilateral breast enlargement.

Implications:

• This case underscores the importance of considering isoniazid as a potential cause of drug-induced gynaecomastia in patients undergoing tuberculosis treatment.
• Awareness of this rare side effect can aid clinicians in timely diagnosis and management.
• Further investigation into the precise mechanism of isoniazid-induced gynaecomastia may be warranted.