II. Indications
- Active Tuberculosis
- Mycobacterium Avium Complex in HIV (off-label use)
III. Mechanism
- Bacteriostatic
- Inhibits arabinogalactan synthesis (key component of the Mycobacterial cell wall)
- Widely distributes including CNS, and concentrates in tubercles
IV. Precautions
- Drug resistance emerges rapidly
- Must be used with other antituberculous drugs
V. Dosing
- Dose based on estimated Lean Body Mass
- Ethambutol is always combined with other agents
- Adult: 15-25 mg/kg (max 1600 mg/day) orally daily
- Weight 40 to 55 kg: 800 mg/day
- Weight 56 to 75 kg: 1200 mg/day
- Weight 79 to 90 kg: 1600 mg/day
- Child: 15-25 mg/kg (max 1000 mg/day) orally daily
-
Renal Dosing
- Reduce dose in Renal Insufficiency
VI. Adverse Effects
-
Vision changes (obtain dilated Eye Exam prior to starting Ethambutol)
- Decreased Visual Acuity
- Retrobulbar Optic Neuritis (2.25% of patients)
- Associated with a loss of central Vision
- Typically reversible
- Peripheral Neuropathy
- Rash
VII. Safety
- Pregnancy Category C
- Considered safe in Lactation
VIII. Monitoring
- Baseline
- Serum Creatinine
- Renal Dosing may be needed due to primarily Renal Clearance
- Visual acquity
- Color Perception
- Serum Creatinine
- Monthly retesting
- Visual acquity
- Color Perception
- Other monitoring
- Consider monitoring blood levels in weight >90 kg
IX. Drug Interactions
- Avoid Antacids with aluminum hydroxide for at least 4 hours after dose
X. Resources
- Ethambutol Tablet (DailyMed)
XI. References
- (2019) Presc Lett, Resource #350309, Tuberculosis Treatment in Adults: FAQ
- (2012) Med Lett Drugs Ther 10(116): 29-36
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Related Studies
| ethambutol (on 12/21/2022 at Medicaid.Gov Survey of pharmacy drug pricing) | ||
| ETHAMBUTOL HCL 400 MG TABLET | Generic | $0.66 each |
Ontology: Ethambutol (C0014964)
| Definition (NCI) | An antibiotic with bacteriostatic, antimicrobial and antitubercular properties. Ethambutol interferes with the biosynthesis of arabinogalactan, a major polysaccharide of the mycobacterial cell wall. It inhibits the polymerization of cell wall arabinan of arabinogalactan and lipoarabinomannan by blocking arabinosyl transferases and induces the accumulation of D-arabinofuranosyl-P-decaprenol, an intermediate in arabinan biosynthesis. This results in halting bacterial growth. |
| Definition (MSH) | An antitubercular agent that inhibits the transfer of mycolic acids into the cell wall of the tubercle bacillus. It may also inhibit the synthesis of spermidine in mycobacteria. The action is usually bactericidal, and the drug can penetrate human cell membranes to exert its lethal effect. (From Smith and Reynard, Textbook of Pharmacology, 1992, p863) |
| Definition (CSP) | antitubercular agent that inhibits the transfer of mycolic acids into the cell wall of the tubercle bacillus; it may also inhibit the synthesis of spermidine in mycobacteria. |
| Concepts | Pharmacologic Substance (T121) , Organic Chemical (T109) |
| MSH | D004977 |
| SnomedCT | 24450004, 387129004 |
| LNC | LP15625-4, MTHU008452 |
| English | Ethambutol, ethambutol, 1-Butanol, 2,2'-(1,2-ethanediyldiimino)bis-, (S-(R*,R*))-, Ethambutol [Chemical/Ingredient], ETHAMBUTOL, Ethambutolol, Ethambutol (product), Ethambutol (substance) |
| Swedish | Etambutol |
| Czech | ethambutol |
| Finnish | Etambutoli |
| Russian | ETAMBUTOL, ЭТАМБУТОЛ |
| Japanese | 塩酸エタンブトール, エタンブトール |
| Polish | Etambutol |
| Spanish | etambutol (producto), etambutol (sustancia), etambutol, Etambutol |
| French | Éthambutol |
| German | Ethambutol |
| Italian | Etambutolo |
| Portuguese | Etambutol |
