As the core drug for the treatment of multidrug-resistant tuberculosis, the use and dosage of Bedaquiline should strictly follow the weight stratification scheme. For special populations, the dosage should be adjusted according to the liver and kidney functions and age characteristics. The following provides a systematic explanation from two aspects: standard dosing regimens and adjustments for special populations.

1. Usage and dosage

(1) Adult standard protocol: Take 400mg orally daily for the first 2 weeks, then switch to 200mg three times a week for the next 22 weeks, with a total duration of 24 weeks. It should be used in combination with at least 3 sensitive anti tuberculosis drugs.

(2) Weight adjustment: For those weighing less than 50kg, the dosage can be reduced to 300mg/day for the first 2 weeks, but 200mg/time is still required during the maintenance period to ensure effective blood drug concentration.

(3) Medication timing: It is recommended to take it immediately after meals. A low-fat diet can increase bioavailability by 20%, and avoid taking it with high-fat foods.

2. Medication for special populations

(1) Liver dysfunction

Mild impairment (Child Pugh A): No dose adjustment is required, but ALT needs to be monitored monthly and stopped when it increases by more than 3 times ULN.

Moderate to severe impairment (Child Pugh B/C): contraindicated, as decreased drug clearance can double the risk of QT prolongation.

(2) Renal insufficiency

Mild to moderate impairment (eGFR ≥ 30mL/min): Regular dosage use, renal excretion ratio<5% without adjustment.

Severe damage (eGFR<30mL/min): Lack of data, it is recommended to reduce dosage by 50% and closely monitor electrocardiogram.

(3) Elderly patients

Patients aged ≥ 65 years: starting at standard dose, but requiring enhanced QT interval monitoring and weekly electrocardiogram examination due to reduced clearance rate.

(4) Children and adolescents

Prohibited for those under 18 years old: Lack of safety and efficacy data, alternative treatment options need to be selected.

(5) Pregnancy and lactation period

Pregnant women are prohibited: Animal studies have shown lethal effects on embryos, and women of childbearing age should use dual contraception measures when taking medication.

Breastfeeding prohibition: Medications may be secreted through breast milk. Avoid breastfeeding during treatment and for 3 months after discontinuation of medication.