What is the maximum recommended dosage of Ethambutol (Ethambutol hydrochloride) per day?

From the Guidelines

The maximum recommended dosage of Ethambutol (Ethambutol hydrochloride) is 15 mg/kg per day (1.0 g/day) for adults, as stated in the most recent and highest quality study available 1.

Key Considerations

• For persons greater than 59 years of age, the dose should be reduced to 10 mg/kg per day (750 mg) 1.
• The dosing frequency should be reduced to 12--15 mg/kg two or three times per week in persons with renal insufficiency 1.
• It's essential to monitor visual acuity and color discrimination regularly during treatment, as Ethambutol can cause optic neuritis, particularly at higher doses or with prolonged use.
• Patients should be instructed to report any visual changes immediately, and baseline visual testing should be performed before initiating therapy.

Dosing Regimens

• The typical daily dose ranges from 15 mg/kg, with 15 mg/kg being the most common maintenance dose.
• When using intermittent dosing regimens, the maximum recommended dose is not explicitly stated as 50 mg/kg two or three times weekly in the most recent study, but rather the dose should be adjusted based on renal function and other factors 1.

Special Populations

• For children, the dose may need to be adjusted based on age and weight, with a maximum dose of 15-25 mg/kg per day for children with suspected or proven resistance to isoniazid or rifampin 1.
• For patients with HIV, the treatment regimen should be carefully reviewed to ensure optimal treatment for both TB and HIV and to minimize potential toxicities and drug-drug interactions 1.

From the FDA Drug Label

DOSAGE AND ADMINISTRATION Ethambutol hydrochloride should not be used alone, in initial treatment or in retreatment. Ethambutol hydrochloride should be administered on a once every 24-hour basis only. In patients who have not received previous antituberculous therapy, administer ethambutol hydrochloride 15 mg/ kg (7 mg/lb) of body weight, as a single oral dose once every 24 hours. In patients who have received previous antituberculous therapy, administer ethambutol hydrochloride 25 mg/kg (11 mg/lb) of body weight, as a single oral dose once every 24 hours. After 60 days of ethambutol hydrochloride administration, decrease the dose to 15 mg/kg (7 mg/lb) of body weight, and administer as a single oral dose once every 24 hours. Weight-Dose Table 25 mg/kg (11 mg/lb) Schedule ... 219 and Over Over 99 ----------------- 2500

The maximum recommended dosage of Ethambutol (Ethambutol hydrochloride) per day is 2500 mg for patients weighing over 99 kg (or 219 lbs), as a single oral dose once every 24 hours, for the initial 60 days of treatment in patients who have received previous antituberculous therapy 2.

From the Research

Ethambutol Maximum Dosage

The maximum recommended dosage of Ethambutol (Ethambutol hydrochloride) per day is a crucial aspect of its administration, particularly in the treatment of tuberculosis. Several studies have investigated the optimal dosage, efficacy, and toxicity of Ethambutol in both adults and children.

Recommended Dosage

• The usual daily dose of Ethambutol should be 15 mg/kg/day, as proposed by 3.
• However, a study published in 4 suggests that children can be given Ethambutol in daily doses of 20 mg/kg (range 15-25 mg/kg) without undue concern.
• Another study 5 recommends calculating the Ethambutol dosage based on body surface area (867 mg/m2) rather than body weight, leading to higher dosages especially in younger children.

Toxicity and Efficacy

• Ocular toxicity is a significant concern with Ethambutol administration, and its occurrence is dose-related 3, 4, 6.
• A study published in 4 found that the occurrence of ocular toxicity was >40% in adults at doses of >50 mg/kg, and 0-3% at a dose of 15 mg/kg/daily.
• In children, ocular toxicity occurred in 0.7% of cases, and relapses in 0.8% 5.

Special Considerations

• Patients with comprehension or communication difficulties may require regular formal ophthalmological evaluation (e.g., monthly) if receiving higher doses of Ethambutol 3.
• Alternative antituberculous agents should be considered due to the potential for serious visual impairment associated with Ethambutol 6.