Ethambutol

Pronunciation: eth-AM-byoo-tol.

Generic name
ethambutol hydrochloride
Brand names
Myambutol, Etibi
Drug class
Antimycobacterial agent (antituberculosis agent)
Form
Tablet (100 mg or 400 mg)
Route
Oral
Legal status
Prescription-only

Availability and supply rules vary by country

Trade names by country: United States · United Kingdom · Canada · Australia · New Zealand

Australia: Myambutol (5), Ethambutol Lupin (5) · Full directory

What ethambutol hydrochloride is and how it works

Ethambutol is a prescription-only antituberculosis medicine used together with other TB medicines to treat tuberculosis. It works by slowing the growth of the bacteria that cause TB. (1)

Ethambutol is always taken as part of a combination of TB medicines, exactly as your prescriber directs, usually once a day. Its most important risk is a dose-related effect on vision, which is why regular eye checks are a required part of treatment -- tell your prescriber immediately about any change in your eyesight, even if it seems minor.

Mechanism of action: how ethambutol hydrochloride works

Ethambutol is bacteriostatic against actively dividing Mycobacterium tuberculosis and M. bovis (MIC 0.5-8 microgram/mL). It appears to inhibit synthesis of one or more metabolites, impairing cell metabolism, arresting bacterial multiplication, and causing cell death in susceptible organisms. (1) (2) (4)

What ethambutol hydrochloride is used for

Tuberculosis (all forms), always in combination therapy

Used together with at least one other antituberculosis medicine to treat pulmonary tuberculosis and other forms of TB, including tuberculous meningitis. Ethambutol is never used as the only TB medicine, since resistance can develop rapidly if it is used alone. (1) (2) (4)

Before taking ethambutol hydrochloride

Do not take / not appropriate for

  • Do not take ethambutol if you have optic neuritis (inflammation of the optic nerve affecting vision), unless your prescriber judges that it is still necessary for your treatment. (all countries) (1) (2) (4)
  • Do not take ethambutol if you have had a hypersensitivity reaction to it. (all countries) (1)
  • Ethambutol is generally not used in young children or anyone else who cannot reliably notice and report changes in their own vision, since eyesight cannot be adequately monitored in that situation. (all countries) (1) (4)

Tell your clinician about

  • Any existing eye conditions, including cataracts, recurrent eye inflammation, or diabetic eye disease affecting the retina.
  • Any kidney problems, since your dose needs to be adjusted for reduced kidney function.
  • Any history of gout or high uric acid levels.
  • All other medicines you take, especially antacids containing aluminium hydroxide.
  • Pregnancy, plans for pregnancy, or breastfeeding.
(1) (2)

How to take ethambutol hydrochloride

  • Take exactly as your prescriber directs, usually as a single dose once every 24 hours, together with your other TB medicines.
  • Ethambutol may be taken with food if it upsets your stomach.
  • Do not take aluminium-hydroxide-containing antacids at the same time as ethambutol -- these reduce how much is absorbed; ask your pharmacist how to space them out.
  • Attend every scheduled eye examination and blood test for the full course of treatment, even if you feel well.
(1)

Procedures and treatment changes

Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (1) (3) (2) (4) (5) (6)

Missed dose

If you forget a dose, take it as soon as you remember unless it is almost time for your next dose -- in that case, skip the missed dose and continue your normal schedule. Do not take a double dose to make up for a missed one.

Overdose

Seek urgent medical attention or contact a poison control centre if an overdose is suspected. A reported symptom of overdose is a change in vision. (4)

Side effects

Side effects and their urgency vary; report severe, persistent, or concerning symptoms.

Loss of appetite, nausea, vomiting, or abdominal pain.

What to notice: Loss of appetite, nausea, vomiting, or abdominal pain.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1)

Headache, dizziness, or a general feeling of being unwell.

What to notice: Headache, dizziness, or a general feeling of being unwell.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1)

Joint pain related to raised uric acid levels.

What to notice: Joint pain related to raised uric acid levels.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1) (2)

Numbness or tingling (peripheral neuropathy) -- uncommon.

What to notice: Numbness or tingling (peripheral neuropathy) -- uncommon.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (2)

Serious warnings

Any change in vision (blurred vision, reduced sharpness, colour changes, or a blind spot) — high caution

Symptoms: Blurred or dimmed vision, difficulty telling red from green, reduced side (peripheral) vision, or a patch of missing vision.

Action: Tell your prescriber immediately about any visual change, no matter how small it seems -- your prescriber will arrange an eye assessment and decide whether ethambutol needs to be stopped. Vision problems are usually reversible if the medicine is reassessed early, but can become permanent if ignored. (1) (2) (4)

Severe skin reaction (Stevens-Johnson syndrome, toxic epidermal necrolysis, or DRESS) — emergency

Symptoms: Widespread rash or blistering, peeling skin, mouth or eye sores, fever, or swollen glands.

Action: Seek emergency medical help immediately -- these reactions can be life-threatening. A clinician will decide whether ethambutol needs to be stopped and will advise against restarting it afterward. (4) (2)

Signs of liver problems — emergency

Symptoms: Yellowing of the skin or eyes, unusual tiredness, loss of appetite, or dark urine.

Action: Contact your prescriber promptly, or seek emergency help if severe -- liver toxicity, including fatal cases, has been reported. (1)

Signs of a serious allergic or hypersensitivity reaction — emergency

Symptoms: Rash with fever, joint pain, swollen glands, breathing difficulty, or facial/throat swelling.

Action: Seek emergency medical help immediately. (1)

Interactions

  • Antacids containing aluminium hydroxide reduce the amount of ethambutol your body absorbs. Space these apart from your ethambutol dose as your pharmacist advises. (1) (2)

Pregnancy, breastfeeding, kidney/liver function, age

Pregnancy

Ethambutol should be used in pregnancy only if the benefit is judged by your prescriber to outweigh potential risk. Animal studies at high doses showed effects on the developing fetus; discuss the balance of risks and benefits of treating TB during pregnancy with your prescriber. (1) (3) (2) (4) (5) (6)

Breastfeeding

Ethambutol passes into breast milk. UK labelling advises against breastfeeding during treatment; discuss feeding options with your prescriber. (1) (3) (2) (4) (5) (6)

Children

Not recommended in children under 13, and generally avoided in children whose vision cannot be reliably monitored (under about 6 years), because safe use has not been established. (1) (3) (2) (4) (5) (6)

Elderly

No specific dose adjustment based on age alone is described beyond the same individualised, weight- and kidney-function-based dosing used for adults generally. (1) (3) (2) (4) (5) (6)

Hepatic_impairment

Liver problems should be discussed with your prescriber; periodic liver function monitoring is recommended during long-term treatment. (1) (3) (2) (4) (5) (6)

Renal_impairment

Reduced kidney function requires a lower dose and/or less frequent dosing, since ethambutol is cleared through the kidneys and reduced clearance raises the risk of toxicity, including the vision-related risk. (1) (3) (2) (4) (5) (6)

Source_ids

US-DAILYMED-ETHAMBUTOL-2026,UK-EMC-ETHAMBUTOL-2025,CA-HC-ETIBI-PM-2025 (1) (3) (2) (4) (5) (6)

Monitoring

Before starting

  • Baseline eye examination: visual acuity, colour discrimination, and visual field (perimetry) testing
  • Baseline kidney function
  • Baseline liver function
  • Baseline uric acid level where relevant

During treatment

  • Repeat eye examinations periodically, monthly if the dose exceeds 15 mg/kg per day.
  • Being asked regularly about any blurred vision or other visual symptoms.
  • Periodic kidney, liver, and blood count checks during longer courses of treatment.
  • Periodic uric acid checks, since elevated levels can trigger gout.
(1) (2) (4)

Storage

Store at room temperature, 20-25°C (68-77°F); brief excursions between 15-30°C are permitted. Protect from light and moisture. Do not use if the blister pack is torn or broken.

Professional information

Clinician-facing context only, sourced from the current US FDA, UK SmPC, and Health Canada product monograph; verify against the current full label before prescribing.

United States / United Kingdom / Canada

Indication: Tuberculosis, combination therapy

Dose summary: Initial treatment (treatment-naive): 15 mg/kg PO once daily. Retreatment: 25 mg/kg once daily for 60 days or until cultures negative, then step down to 15 mg/kg daily. Intermittent regimens: 50 mg/kg (max 2.5 g) twice weekly, or 25-30 mg/kg (max 2.5 g) three times weekly, both combined with other antituberculous agents given on the same schedule. Not recommended under 13 years (US/Canada); not recommended if vision cannot be monitored (roughly under 6 years).

Renal context: Renal impairment requires reduced dose and/or frequency; UK SmPC specifies for creatinine clearance under 30 mL/min: 15-25 mg/kg (max 2.5 g) three times weekly with plasma level monitoring. Toxic effects are more common with renal impairment. (1) (2) (4)

Mechanism of action

Hepatic guidance

Renal, hepatic, and haematopoietic tests should be performed periodically during long-term therapy; liver toxicity including fatalities has been reported.

Overdose note

Reported overdose is associated with a change in vision; management is supportive, guided by regional poison control services, with prompt ophthalmologic assessment. (1) (2) (4)

Frequently asked questions

Is ethambutol available in the US, UK, Europe, Canada, Australia, and New Zealand?

Yes. It is approved and available in all of these regions as part of combination tuberculosis treatment, though in New Zealand its availability is confirmed through the government funding schedule rather than a standalone product data sheet. (1) (3) (2) (4) (5) (6)

Why do I need regular eye tests while taking ethambutol?

Ethambutol can cause a dose-related decrease in vision from optic nerve inflammation. Baseline and periodic eye examinations (visual acuity, colour vision, and visual field testing) are required so that any change can be caught and reassessed early by your prescriber, since damage is often reversible if caught promptly but can become permanent if missed. (1) (2) (4)

Can I take ethambutol on its own?

No. Ethambutol is always used together with at least one other antituberculosis medicine. Using it alone allows resistant bacteria to develop rapidly. (1) (2)

What is the mechanism of action of ethambutol hydrochloride?

Ethambutol is bacteriostatic against actively dividing Mycobacterium tuberculosis and M. bovis (MIC 0.5-8 microgram/mL). It appears to inhibit synthesis of one or more metabolites, impairing cell metabolism, arresting bacterial multiplication, and causing cell death in susceptible organisms. (1) (2) (4)

What is the generic name of Ethambutol?

The generic name is ethambutol hydrochloride. It is sold under brand names including Myambutol, Etibi. (1)

What class of drug is ethambutol hydrochloride?

Ethambutol is classed as: Antimycobacterial agent (antituberculosis agent). (1)

References

  1. ETHAMBUTOL HYDROCHLORIDE tablet -- full prescribing informationU.S. Food and Drug Administration / DailyMed (NIH), full prescribing information · United States · dated 2026-01-01 · accessed 2026-07-29 · source 1
  2. Ethambutol 400 mg film-coated tablets -- Summary of Product Characteristicselectronic medicines compendium (emc), United Kingdom -- Brown & Burk UK Limited · United Kingdom · dated 2025-06-11 · accessed 2026-07-29 · source 2
  3. National registers of authorised medicines -- EMA guidance on verifying nationally authorised productsEuropean Medicines Agency (EMA) -- ethambutol is nationally authorised across EU member states via national procedures (a long-established, off-patent WHO Essential Medicines List antituberculosis agent; no centralised EMA EPAR exists for it) · European Union · dated 2026-01-01 · accessed 2026-07-29 · source 3
  4. ETIBI (ethambutol hydrochloride) Tablets, 100 & 400 mg -- Product Monograph Including Patient Medication InformationHealth Canada product monograph, Bausch Health Canada Inc. · Canada · dated 2025-09-26 · accessed 2026-07-29 · source 4
  5. MYAMBUTOL (ethambutol hydrochloride) 400 mg and 100 mg tablets -- ARTG registrationTherapeutic Goods Administration (TGA), Australia · Australia · dated 2008-02-20 · accessed 2026-07-29 · source 5
  6. Ethambutol hydrochloride -- New Zealand Pharmaceutical Schedule listing and Healthify consumer medicine summaryPharmac (Pharmaceutical Management Agency, New Zealand) Schedule Online, cross-referenced with Healthify He Puna Waiora (New Zealand's government-funded consumer health information service) · New Zealand · dated 2026-01-01 · accessed 2026-07-29 · source 6

Brand names by country

Single-ingredient ethambutol hydrochloride names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.

Priority countries

United States

  • Ethambutol Hydrochloride (generic; originator Myambutol) (1)FDA approved currently labeled · 100 mg, 400 mg · multiple generic manufacturers

United Kingdom

  • Ethambutol 400 mg / 100 mg film-coated tablets (2)MHRA licensed emc smpc confirmed · 100 mg, 400 mg · Brown & Burk UK Limited (PL 25298/0274)

Canada

  • ETIBI

Australia

  • Myambutol (5)TGA ARTG registered 2008-02-20 confirmed · 100 mg, 400 mg · Aspen Pharmacare Australia Pty Ltd
  • Ethambutol Lupin (5)TGA ARTG registered 2022-07-13 confirmed · 400 mg · Lupin Australia Pty Limited

New Zealand

  • Ethambutol hydrochloride (unbranded/generic) (6)Pharmac funded confirming Medsafe consent no standalone datasheet located · 100 mg, 400 mg · not specified in fetched sources
View brands in additional countries.

European Union

Ethambutol (nationally authorised generic, various EU member-state marketing authorisation holders) (3)

This page provides general reference information about ethambutol and is not a substitute for advice from the prescriber managing your treatment. All dosing and treatment decisions should be made with your prescriber.

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