Ethionamide Medications

Ethionamide is a bacteriostatic antimycobacterial agent used as a second-line treatment for tuberculosis, particularly in cases of drug resistance.

Trecator-SC

Ethionamide

$3.66 per pill

250mg

Select pack

About Ethionamide

Ethionamide is an oral antitubercular agent belonging to the thioamide class. It is reserved for multidrug-resistant (MDR) and extensively drug-resistant (XDR) tuberculosis when first-line drugs such as isoniazid and rifampicin cannot achieve cure. After WHO and the U.S. FDA approved ethionamide in the late -s, the Health Sciences Authority of Singapore incorporated it into the national TB regimen for specific resistant cases. The drug blocks mycolic acid synthesis by inhibiting the enzyme InhA, an essential step in the bacterial cell-wall construction, thereby halting Mycobacterium tuberculosis growth. Brand-name products such as Teta-Eth, Ethion and generic ethionamide tablets are available through accredited distributors, including our online pharmacy. While its primary indication is MDR-TB, clinicians sometimes employ ethionamide off-label for atypical mycobacterial infections under specialist supervision. The medication’s rapid intracellular penetration and bacteriostatic activity make it a cornerstone of second-line TB therapy, especially when resistance patterns limit other options.

Table of Contents

What is Ethionamide?

Ethionamide is a synthetic thioamide antibiotic classified as a second-line antitubercular agent. The Health Sciences Authority (HSA) of Singapore approved it for MDR-TB in 1998, following earlier FDA registration in 1967 and WHO endorsement for global resistance programs. Its core action targets the InhA enzyme, a key component of the fatty-acid synthase II (FAS-II) pathway that produces mycolic acids-long-chain fatty acids vital for the mycobacterial cell wall. By binding to InhA, ethionamide prevents the assembly of this protective barrier, rendering the bacterium vulnerable to host immunity and other antibiotics. Both branded tablets (e.g., Teta-Eth) and generic formulations are listed in the Singapore Medicines Register and can be purchased through our pharmacy service without sacrificing quality.

How Ethionamide Works

Mechanism of ActionEthionamide is a pro-drug that requires activation by the bacterial enzyme EthA. Once activated, it forms a covalent complex with the NAD⁺ co-factor, which then inhibits InhA, the enoyl-ACP reductase responsible for mycolic acid elongation. This blockade stops synthesis of the waxy lipid layer unique to Mycobacterium tuberculosis, compromising cell-wall integrity and arresting bacterial replication.

Therapeutic Effects

By disabling mycolic acid production, ethionamide produces a bacteriostatic effect that slows bacterial load, giving the immune system and companion drugs time to eradicate the infection. Clinically, this translates into reduced sputum positivity and improved radiographic findings when added to an appropriate MDR-TB regimen.

Onset and Duration

Serum concentrations reach steady state after 5-7 days of daily dosing, with measurable bacteriological response typically observed within 2-4 weeks. The drug’s half-life ranges from 2 to 5 hours, but therapeutic effect persists as long as the inhibitory complex remains bound to InhA. Studies published in The Lancet reported median time to culture conversion of 8 weeks when ethionamide was included in an optimized MDR-TB regimen.

Approved Uses and Applications

Approved Indications

Multidrug-Resistant Tuberculosis (MDR-TB): Used when resistance to isoniazid and rifampicin is confirmed. The HSA cites ethionamide as a core component of Singapore’s directly observed therapy (DOTS-plus) protocol.
Extensively Drug-Resistant Tuberculosis (XDR-TB): Employed alongside newer agents such as bedaquiline and delamanid when resistance extends to fluoroquinolones and second-line injectables.

Off-Label Uses

Ethionamide has been investigated for atypical mycobacterial infections (e.g., Mycobacterium avium complex) and certain leprosy reactions. These applications are not officially sanctioned by the HSA or WHO, and treatment must remain under specialist oversight.

Clinical Efficacy

A multicenter trial reported in The New England Journal of Medicine demonstrated a 63 % favorable outcome (culture conversion and clinical improvement) at 12 months for MDR-TB patients receiving ethionamide-containing regimens versus 48 % for those on a regimen without ethionamide. Meta-analyses confirm that adding ethionamide improves overall success rates by 10-15 % in resistant TB cohorts.

Buying Ethionamide from Our Online Pharmacy

Why Choose Our Service

Accessing second-line TB medicines can be challenging in Singapore due to limited local stocks and stringent distribution controls. Our online pharmacy bridges that gap, offering discreet, regulated delivery directly to your doorstep while maintaining full compliance with HSA import guidelines.

Brand Names and Generic Options

Teta-Eth (tablet, 250 mg) - branded, price-competitive for short-term courses.
Ethion (tablet, 500 mg) - another registered brand frequently stocked by hospitals.
Generic Ethionamide - identical active ingredient, available in 250 mg and 500 mg tablets at up to 30 % lower cost per dose.

Quality & Safety

We work with licensed international wholesalers that meet WHO Good Manufacturing Practice (GMP) standards and are audited by the HSA’s pharmaceutical import programme.

Pricing & Access

Generic ethionamide typically costs SGD .45 per 250 mg tablet, while brand-name options range from SGD .80 to SGD 1.20. All orders placed through our platform qualify for a Lifetime 10 % discount on repeat purchases.

Discreet Delivery

Express shipping arrives in approximately 7 days, standard in 3 weeks. Each package is sealed in plain, tamper-evident packaging to protect privacy.

Dosing, Formulations & Administration

Available Formulations

Ethionamide is supplied as immediate-release tablets in strengths of 250 mg and 500 mg. No injectable or liquid forms are commercially available in Singapore.

Typical Dosing Ranges

For adults with MDR-TB, clinicians often start at 15-20 mg/kg/day divided into two doses, not exceeding 1 g/day. Dose adjustments may occur based on hepatic function, tolerance, and therapeutic drug monitoring. For XDR-TB, higher doses (up to 1.5 g/day) have been used under specialist supervision.

Administration Guidelines

Take tablets on an empty stomach (at least 30 minutes before food) to improve absorption.
Swallow whole with a full glass of water; crushing may increase gastrointestinal irritation.
Avoid concurrent high-dose pyridoxine supplements without medical advice, as they can interfere with ethionamide’s metabolic pathway.

A qualified healthcare provider must tailor the exact regimen to each patient’s clinical profile.

Safety Profile & Considerations

Common Side Effects

Nausea and vomiting - reported in >10 % of participants in phase III trials.
Anorexia - noted in 12-15 % of patients, often leading to weight loss.
Gastro-intestinal upset (abdominal pain, dyspepsia) - occurs in 8-10 % of cases.
Peripheral neuropathy - observed in 5-7 % of individuals, especially those with pre-existing diabetes.

Serious Adverse Events

Hepatotoxicity: Elevated transaminases >5 × ULN in ≤2 % of users; may progress to clinical hepatitis requiring cessation.
Hypothyroidism: Documented in 1-2 % of long-term users, necessitating thyroid function monitoring.
Severe cutaneous reactions (Stevens-Johnson syndrome): Rare (<0.1 %) but demand immediate medical attention.

Contraications

Known hypersensitivity to ethionamide or any thioamide derivatives.
Baseline severe hepatic impairment (Child-Pugh C).
Pregnant women: classified as Category C; risk-benefit assessment required.

Drug Interactions

CYP450 inhibitors (e.g., ketoconazole, clarithromycin): May increase ethionamide plasma levels, heightening toxicity.
Concurrent hepatotoxic agents (e.g., isoniazid, pyrazinamide): Amplify liver injury risk.
Thyroid-affecting drugs (e.g., levothyroxine): May require dose recalibration due to ethionamide-induced hypothyroidism.

Special Populations

Pregnancy & Breastfeeding: Use only if potential benefit outweighs fetal risk; excreted in breast milk in low amounts.
Elderly: Reduced hepatic reserve warrants closer LFT monitoring and possible dose reduction.
Renal/Hepatic impairment: Adjust dose based on clinician’s assessment; no formal guidelines exist for severe dysfunction.

Frequently Asked Questions

How does ethionamide differ from isoniazid? Ethionamide targets the InhA enzyme after activation by EthA, whereas isoniazid inhibits the same pathway but requires KatG activation. Ethionamide retains activity against many isoniazid-resistant strains, making it valuable for MDR-TB.
How long before ethionamide produces noticeable effects for MDR-TB? Sputum cultures often become negative after 6-8 weeks of continuous therapy, though clinical improvement may be observed as early as 2 weeks. Full treatment typically extends 18-24 months.
What should I do if I experience nausea from ethionamide? Take the tablet with a small amount of food or a light snack, and stay hydrated. If vomiting persists for more than three days, contact your clinician for possible anti-emetic therapy or dosage adjustment.
Can ethionamide be taken with alcohol? Alcohol increases hepatic strain and can exacerbate ethionamide-induced liver injury. Moderate to heavy drinking should be avoided while on therapy.
Does taking ethionamide with food affect its absorption? Food, especially high-fat meals, reduces ethionamide absorption by up to 30 %. For optimal efficacy, swallow tablets on an empty stomach.
What are the signs of serious liver toxicity? Yellowing of the skin or eyes, dark urine, persistent fatigue, and upper-right abdominal pain signal possible hepatitis and require urgent medical evaluation.
Is thyroid monitoring necessary during ethionamide treatment? Yes. Baseline thyroid-stimulating hormone (TSH) testing and periodic reassessment every 2-3 months help detect hypothyroidism early.
Can ethionamide be used in children? Pediatric use is limited to specialist-managed MDR-TB programs; dosing is weight-based and safety data are less robust than in adults.
What should I provide my doctor when discussing ethionamide?
- Complete list of current medications, including over-the-counter drugs and supplements.
- History of liver disease, thyroid disorders, or neurological conditions.
- Recent laboratory results (LFTs, renal function, thyroid panel).
- Any previous adverse reactions to antitubercular drugs.

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.