What medications are safe for treating tuberculosis (TB) in pregnancy?

Safe Medications for Treating Tuberculosis in Pregnancy

Isoniazid, rifampin, and ethambutol are the recommended first-line medications for treating tuberculosis during pregnancy, as they are safe and do not cause fetal malformations. 1, 2

First-Line Treatment Regimen

• Treatment of tuberculosis in pregnant women should be initiated promptly when suspicion of disease is moderate to high because untreated tuberculosis poses a greater risk to both mother and fetus than the medications 2, 3
• The initial treatment regimen should consist of isoniazid, rifampin, and ethambutol 1, 2
• If pyrazinamide is not included in the initial treatment regimen, the minimum duration of therapy is 9 months 1, 2
• Pyridoxine (vitamin B6) supplementation (25 mg/day) should be given to all pregnant women receiving isoniazid to prevent neurotoxicity 1, 4

Medications to Avoid During Pregnancy

• Streptomycin should not be used in pregnant women as it can cause congenital deafness in approximately 17% of exposed fetuses 1, 2
• Other aminoglycosides (kanamycin, amikacin, capreomycin) should also be avoided as they presumably share the same ototoxic potential 2, 3
• Pyrazinamide is generally not recommended in pregnancy in the United States due to insufficient data on teratogenicity, although international organizations like WHO do recommend its routine use 1, 5
• Fluoroquinolones should be avoided if possible during pregnancy due to their association with arthropathies in young animals 1, 2

Monitoring During Treatment

• Baseline liver function tests should be obtained before starting treatment 4
• Regular monitoring of liver function is essential, particularly during the first two months of treatment 4, 1
• Women belonging to minority groups, particularly in the post-partum period, may have a higher risk of isoniazid-associated hepatitis and should be monitored more closely 4

Special Considerations

• Breastfeeding should not be discouraged for women being treated with first-line anti-tuberculosis drugs (isoniazid, rifampin, ethambutol) as the small concentrations in breast milk do not produce toxic effects in the nursing infant 1, 2
• However, drugs in breast milk should not be considered effective treatment for tuberculosis in the nursing infant 1, 2
• Rifampin may alter the metabolism of other drugs due to liver enzyme induction, which should be considered when managing pregnant women on other medications 3

Treatment Duration and Follow-up

• For standard drug-susceptible tuberculosis, if pyrazinamide is not included, the 9-month regimen typically consists of isoniazid and rifampin throughout, with ethambutol in the initial phase until drug susceptibility is confirmed 1
• Close monitoring of treatment response is essential, with clinical and radiographic findings often used to judge response in cases where bacteriologic evaluation may be limited 2
• For multidrug-resistant tuberculosis (MDR-TB), consultation with an expert in tuberculosis management is recommended 1

Important Caveats

• Termination of pregnancy is not medically indicated for women taking first-line anti-tuberculosis drugs 1, 6
• Drug susceptibility testing should be performed on organisms initially isolated from all patients with newly diagnosed tuberculosis to guide appropriate therapy 4
• If the disease is caused by drug-resistant organisms, treatment must be individualized based on susceptibility studies 4, 5