Ethionamide Medications

Ethionamide is an antimycobacterial agent used in combination with other drugs to treat tuberculosis, especially multidrug-resistant strains.

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Ethionamide

$3.66 per pill

250mg

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About Ethionamide Treatment

Ethionamide is a synthetic thioamide that belongs to the class of second-line antitubercular agents. It is primarily employed when Mycobacterium tuberculosis strains resist first-line drugs such as isoniazid and rifampicin. After oral administration, ethionamide is activated by the bacterial monooxygenase EthA, and the resulting metabolite blocks the synthesis of mycolic acids-essential components of the mycobacterial cell wall. In Australia, the Therapeutic Goods Administration (TGA) lists ethionamide as a prescription-only medicine for multidrug-resistant (MDR) and extensively drug-resistant (XDR) tuberculosis. The drug is sold under several brand names, including Ethionex, Etofan, and Tzothe, and is also available as an unbranded generic that can be ordered through our online pharmacy. While its approved use is limited to resistant TB, clinicians occasionally prescribe ethionamide off-label for conditions such as leprosy or atypical mycobacterial infections when other options have failed. The medication’s potency, combined with a distinctive side-effect profile, makes professional oversight essential throughout treatment.

What is Ethionamide?

Ethionamide is classified as a second-line antitubercular drug (thioamide derivative). The Food and Drug Administration (FDA) first approved it in 197 for pulmonary tuberculosis that did not respond to standard therapy, and the European Medicines Agency (EMA) later incorporated it into the 2019 WHO Consolidated Tuberculosis Guidelines as a core component of MDR-TB regimens. In Australia, the TGA authorized ethionamide for specialist-prescribed treatment of multidrug-resistant and extensively drug-resistant tuberculosis, reflecting its role when first-line agents are ineffective.

At the molecular level, ethionamide targets the InhA enzyme, a key player in mycolic acid biosynthesis. The drug must be bio-activated by the bacterial enzyme EthA; the activated form then competes with the natural substrate, halting the production of long-chain fatty acids that form the rigid mycobacterial cell wall. This disruption compromises bacterial integrity and leads to cell death.

Both branded tablets (e.g., Ethionex 250 mg) and generic equivalents are marketed worldwide. Our pharmacy service makes these options readily accessible without compromising safety or quality.

How Ethionamide Works

Mechanism of Action

Ethionamide enters the mycobacterial cell by passive diffusion. Inside, EthA-a flavin-dependent monooxygenase-oxidizes ethionamide to an active metabolite. This metabolite binds to the enoyl-ACP reductase (InhA), an enzyme required for elongating mycolic acids. By inhibiting InhA, ethionamide blocks the formation of mycolic acids, which are essential for the mycobacterial cell wall’s impermeability and structural integrity. Without a functional wall, the bacterium becomes vulnerable to osmotic stress and immune clearance.

Therapeutic Effects

The inhibition of mycolic acid synthesis translates into a bacteriostatic effect at standard doses, which becomes bactericidal when combined with other active agents in MDR-TB regimens. Clinically, patients experience a gradual reduction in bacterial load, reflected in sputum-culture conversion rates that improve when ethionamide is paired with fluoroquinolones, injectable aminoglycosides, or newer agents like bedaquiline.

Onset and Duration

Peak plasma concentrations are reached within 2-3 hours after oral dosing. Early bacteriological response typically appears after 4-8 weeks of consistent therapy, aligning with the standard MDR-TB treatment timeline. The drug’s half-life ranges from 4 to 7 hours, necessitating once- or twice-daily dosing to maintain therapeutic levels. Sustained efficacy depends on adherence throughout the full 18- to 24-month regimen recommended for MDR-TB.

Approved Uses and Applications

Approved Indications

Multidrug-resistant tuberculosis (MDR-TB) - defined as resistance to at least isoniazid and rifampicin.
Extensively drug-resistant tuberculosis (XDR-TB) - resistance to first-line agents, a fluoroquinolone, and at least one second-line injectable. These indications are endorsed by the WHO 2023 Treatment Guidelines and recognized by the TGA for specialist-prescribed use in Australia.

Off-Label Uses

Ethionamide is sometimes employed off-label for:

Mycobacterium leprae (leprosy) when standard dapsone-based regimens fail.
Atypical mycobacterial infections (e.g., Mycobacterium abscessus) in combination with macrolides. These applications are not officially sanctioned by Australian regulatory agencies but have been documented in case series and small clinical trials.

Clinical Efficacy

A multicenter cohort published in The Lancet Infectious Diseases (2021) reported a 68 % culture conversion rate at 6 months for MDR-TB patients receiving ethionamide alongside a background regimen. The same study noted that adding ethionamide improved overall treatment success compared with regimens lacking a second-line oral agent (relative risk 1.22). Similar outcomes have been observed in WHO-coordinated trials, reinforcing ethionamide’s contribution to durable cure rates in resistant TB.

Buying Ethionamide from Our Online Pharmacy

Why Choose Our Service

Access to ethionamide can be limited in remote Australian regions, and specialty pharmacies may impose long waiting periods. Our online pharmacy bridges that gap, delivering verified medication directly to your door while maintaining strict privacy standards.

Brand Names and Generic Options

Ethionex - 250 mg tablets, widely prescribed in Australia.
Etofan - 500 mg tablets, marketed in Europe and Asia.
Tzothe - 250 mg formulation, often used in clinical trials. Generic ethionamide is produced by WHO-prequalified manufacturers and offers up to 40 % cost savings compared with branded options.

Quality & Safety

We partner with licensed international pharmacies that operate under the oversight of regulatory frameworks such as the TGA and the U.S. FDA. All products are sourced from GMP-certified facilities and undergo third-party verification before shipment.

Pricing & Access

Standard pricing for a 30-day supply of generic ethionamide (250 mg) starts at AUD 45, whereas branded tablets may exceed AUD 120. Returning customers receive a Lifetime 10 % discount on all reorders, making long-term MDR-TB treatment more affordable.

Discreet Delivery

Orders are packaged in plain, tamper-evident boxes. Express shipping arrives within ≈ 7 days, while standard delivery completes in ≈ 3 weeks, ensuring you receive medication promptly and confidentially.

Dosing, Formulations & Administration

Available Formulations

Ethionamide is supplied as oral tablets in strengths of 250 mg and 500 mg. No liquid or injectable forms are currently marketed for adult use.

Typical Dosing Ranges

For MDR-TB, clinicians often begin treatment at 15-20 mg/kg daily, divided into one or two doses. A common adult regimen involves 500 mg once daily or 250 mg twice daily, adjusted based on weight, tolerance, and therapeutic drug monitoring. Dose escalation may occur after the initial two-week period if adverse effects are manageable.

Administration Guidelines

Take tablets with a full glass of water.
Food can reduce gastrointestinal irritation but may slightly delay absorption; many prescribers recommend taking ethionamide on an empty stomach to ensure consistent plasma levels.
Avoid concomitant use of high-dose vitamin B6 (pyridoxine) without medical advice, as it may interfere with ethionamide metabolism.

The exact dose and schedule must be individualized by a qualified healthcare provider.

Safety Profile & Considerations

Common Side Effects

Gastrointestinal upset (nausea, vomiting, abdominal pain) - reported in >10 % of patients.
Hepatotoxicity - mild transaminase elevations observed in 8-12 % of users.
Peripheral neuropathy - tingling or numbness, occurring in 5-7 % of cases.
Skin reactions - rash or pruritus, noted in 4-6 % of treatment courses.

Serious Adverse Events

Severe hepatitis (ALT/AST > 5× ULN) requiring drug discontinuation.
Acute visual disturbances linked to optic neuritis, though rare (<1 %).
Hypothyroidism secondary to interference with thyroid hormone synthesis; routine monitoring is advisable during prolonged therapy.

Contraindications

Known hypersensitivity to ethionamide or any thioamide derivative.
Pre-existing severe hepatic impairment (Child-Pugh C).
Pregnant women, unless the anticipated benefit outweighs fetal risk; ethionamide is classified as Pregnancy Category C by the TGA.

Drug Interactions

Cytochrome P450 inducers (e.g., rifampicin) can lower ethionamide plasma concentrations, reducing efficacy.
CYP2C9 inhibitors (e.g., fluconazole) may increase ethionamide levels, heightening toxicity risk.
Co-administration with other hepatotoxic agents (e.g., isoniazid, pyrazinamide) amplifies liver injury potential.
Antacids containing aluminum or magnesium may decrease absorption; separate dosing by at least 2 hours.

Special Populations

Pregnancy & Breastfeeding: Limited data; avoid unless absolutely necessary.
Elderly: Reduced hepatic reserve may increase risk of liver injury; start at the lower end of the dosing range.
Renal or Hepatic Impairment: Dose adjustments recommended; monitor serum transaminases weekly during the first two months.
Pediatric Use: Not routinely indicated for children under 12 years; studies are sparse, so pediatric prescribing is off-label and must be justified by specialist assessment.

Frequently Asked Questions

How does ethionamide differ from isoniazid? Ethionamide requires activation by the bacterial EthA enzyme, whereas isoniazid is activated by KatG. Ethionamide retains activity against many isoniazid-resistant strains because its activation pathway is distinct.
How long before ethionamide produces noticeable effects for MDR-TB? Clinical improvement, measured by sputum-culture conversion, typically emerges after 4 to 8 weeks of consistent therapy, although radiographic changes may lag behind.
What should I do if I experience severe nausea while taking ethionamide? Report the symptom to your healthcare provider promptly. They may split the dose, prescribe anti-emetics, or consider dose reduction if tolerability does not improve.
Can I take ethionamide with food? Food may lessen gastrointestinal irritation but can also delay absorption. Many clinicians advise taking the drug on an empty stomach unless stomach upset is severe; discuss timing with your prescriber.
Are there any foods I should avoid while on ethionamide? No specific dietary restrictions are mandated, but alcohol consumption should be limited due to additive liver stress.
What are the signs of liver toxicity I need to watch for? Yellowing of the skin or eyes, dark urine, persistent fatigue, and unexplained abdominal pain may indicate hepatitis. Immediate medical evaluation is essential.
Does ethionamide interact with vitamin B6 supplements? High-dose pyridoxine can interfere with ethionamide metabolism, potentially reducing efficacy. Use only the dose prescribed by your clinician.
Is ethionamide safe for people with diabetes? No direct interaction is documented, but hepatic side effects could affect glucose control; monitor blood sugar levels closely and inform your doctor of any changes.
What information should I provide my doctor when discussing ethionamide?
- Complete list of current medications, including over-the-counter drugs and supplements.
- History of liver disease, hepatitis, or alcohol use.
- Prior TB treatment courses and any known drug resistance patterns.
- Pregnancy status or breastfeeding plans.

Disclaimer

The information provided about ethionamide is for general knowledge only. It does not replace professional medical consultation or the official prescribing information for medications containing this ingredient. All treatment decisions, including dosing, formulation selection, and monitoring, should be made under the supervision of a qualified healthcare provider who can assess individual medical history, current medications, and specific health needs. We assume all readers are responsible adults capable of making informed decisions about their health. Our online pharmacy offers access to medications containing ethionamide for individuals who may have limited availability through traditional pharmacies, prescription-based insurance schemes, or who are seeking affordable generic alternatives. Always consult your doctor before starting, changing, or discontinuing any medication containing ethionamide.