What urinary side effects are associated with isoniazid (Isoniazid) and rifapentine (Rifapentine) treatment for latent tuberculosis?

Urinary Side Effects of Isoniazid and Rifapentine for Latent TB

Urinary side effects are not documented as recognized adverse effects of the isoniazid-rifapentine (3HP) regimen for latent tuberculosis infection according to CDC guidelines. 1

Documented Adverse Effects (Non-Urinary)

The CDC's comprehensive monitoring guidance for 3HP treatment does not include urinary symptoms in its adverse effect profile. The recognized side effects are:

Common Systemic Reactions (~4% of patients)

• Flu-like symptoms (fever, headache, dizziness, nausea, muscle and bone pain) 1
• Rash, itching, red eyes 1
• These typically occur after the first 3-4 doses, beginning approximately 4 hours after medication ingestion 1

Hematologic and Hepatic Effects

• Neutropenia (uncommon) 1
• Elevation of liver enzymes (uncommon) 1
• Drug-related hepatotoxicity occurs in only 0.4% of patients on 3HP 2

Rare Serious Reactions

• Hypotension and syncope (2 cases per 1,000 persons treated) 1
• Thrombocytopenia 1

Important Caveat: Rare Renal Effects

While not a typical urinary side effect, one case report documented rifampicin-induced minimal change disease presenting with nephrotic syndrome and acute renal failure during latent TB treatment. 3 This patient developed:

• Nephrotic syndrome after 25 days of rifampicin and isoniazid 3
• Acute renal failure requiring temporary dialysis 3
• Complete remission after drug cessation and steroid therapy 3

This case suggests that renal function and proteinuria should be monitored, especially during the first few months of therapy, though this is not part of standard CDC monitoring recommendations. 3

Standard Monitoring Protocol

The CDC does not recommend routine urinalysis or renal function monitoring unless clinically indicated. Standard monitoring includes: 1

• Monthly evaluations (in person or by telephone) for adherence and adverse effects 1
• Baseline hepatic chemistry tests (at least AST) for high-risk patients 1
• Patient education to report symptoms immediately, particularly hypersensitivity reactions, rash, or hypotension 1