Perioperative Management of Anti‑Tubercular Therapy

Patients with Normal Baseline Liver Function (AST/ALT < 2 × Normal)

• Continue all anti‑tubercular drugs (RIPE) without interruption throughout the peri‑operative period; routine pre‑operative liver function monitoring is unnecessary unless the patient develops symptoms such as fever, malaise, vomiting, jaundice, or unexplained deterioration. 1

Patients with Moderately Elevated Transaminases (AST/ALT 2‑5 × Normal)

• Continue anti‑tubercular drugs but obtain liver function tests immediately before anesthesia. 2, 1
• Perform weekly liver function monitoring for the first two weeks, then every two weeks until values normalize. 2
• If transaminase levels are stable or decreasing, proceed with surgery while maintaining all TB medications. 1
• Hold hepatotoxic medications only when AST/ALT rises to ≥ 5 × the upper limit of normal or when bilirubin becomes elevated. 2, 1

Patients with Severe Hepatotoxicity (AST/ALT ≥ 5 × Normal or Any Bilirubin Elevation)

• Immediately discontinue rifampicin, isoniazid, and pyrazinamide. 2, 1
• For patients with active, smear‑positive TB or who are clinically unwell, replace the discontinued drugs with streptomycin and ethambutol until liver function recovers. 2, 1
• For patients with non‑infectious TB who are clinically stable, defer anti‑tubercular therapy until liver function returns to normal. 2, 1

Baseline and Pre‑operative Liver Function Assessment

• Baseline AST, ALT, and bilirubin testing is mandatory before initiating anti‑tubercular therapy; repeat pre‑operative testing is required only if the patient exhibits hepatic symptoms or had abnormal baseline results. 1

Hepatotoxicity Timing and Prognosis

• Early hepatotoxicity (within the first 15 days of therapy) is usually due to rifampicin‑enhanced isoniazid toxicity and carries a generally favorable prognosis; late hepatotoxicity (after > 1 month) is more often related to pyrazinamide and has a poorer prognosis. 2, 1

Impact of Modest Transaminase Elevations

• Small, asymptomatic increases in hepatic transaminases are common in pretreatment liver tests of TB patients and do not warrant interruption of therapy. 2, 1

Surgical Timing Considerations

• There is no evidence supporting postponement of elective surgery in patients receiving stable anti‑tubercular therapy with normal liver function. 1

Re‑introduction of Anti‑tubercular Drugs After Hepatotoxicity

• When sequential re‑introduction is required, avoid fixed‑dose combinations; start with isoniazid (low dose, titrate upward), followed by rifampicin, and finally pyrazinamide, each escalated to full dose as tolerated. 2

Treatment of Peritoneal Tuberculosis

Recommended Treatment Regimen

• The American Thoracic Society recommends a 6-month treatment regimen for peritoneal tuberculosis, consisting of an initial phase with four drugs (isoniazid, rifampicin, pyrazinamide, and ethambutol) for 2 months, followed by a continuation phase with two drugs (isoniazid and rifampicin) for 4 months 3
• The initial phase consists of isoniazid, rifampicin, pyrazinamide, and ethambutol, while the continuation phase consists of isoniazid and rifampicin 3
• The recommended dosages for adults are: isoniazid 5 mg/kg (up to 300 mg) daily, rifampicin 10 mg/kg (up to 600 mg) daily, pyrazinamide 35 mg/kg (up to 2.0 g) daily, and ethambutol 15 mg/kg daily 4, 3, 5

Monitoring and Management of Adverse Effects

• Liver function should be evaluated before starting treatment, and monitoring is not necessary for patients without pre-existing liver disease, but should be repeated if symptoms such as fever, malaise, vomiting, jaundice, or unexplained deterioration occur 6, 7
• If liver enzymes (AST/ALT) increase to five times normal or bilirubin increases, rifampicin, isoniazid, and pyrazinamide should be discontinued 6
• Renal function should be evaluated before starting treatment with streptomycin or ethambutol, and these drugs should be avoided in renal insufficiency if possible, with monitoring of serum concentrations and dose adjustment if necessary 6, 5
• Ocular toxicity due to ethambutol requires evaluation of visual acuity using the Snellen chart before prescribing, and patients should be informed to stop the medication immediately if visual symptoms occur 5

Management of Hepatotoxicity

• If hepatotoxicity develops during treatment, the following algorithm should be followed: suspend treatment until liver function normalizes, and then reintroduce drugs sequentially, starting with isoniazid, followed by rifampicin and pyrazinamide 7, 6, 5
• Isoniazid should be started at 50 mg/day and increased to 300 mg/day after 2-3 days, rifampicin should be added at 75 mg/day after 2-3 days without reaction and increased to the full dose, and pyrazinamide should be added at 250 mg/day and increased to the full dose 4

Combined Drug Preparations

• Combined preparations, such as Rifinah and Rimactazid (isoniazid and rifampicin) and Rifater (isoniazid, rifampicin, and pyrazinamide), are available to facilitate compliance, and can be useful for verifying compliance due to the orange/pink coloration of urine caused by rifampicin 4