Generic Ethionamide

Introduction

Ethionamide is an oral antimicrobial agent supplied as 250 mg tablets. It belongs to the class of second-line anti-tuberculosis drugs and is primarily prescribed for multidrug-resistant (MDR) and extensively drug-resistant (XDR) tuberculosis. The medication is manufactured by several licensed pharmaceutical companies and is distributed worldwide in a standard pill form. In addition to its approved use for resistant Mycobacterium tuberculosis infections, clinicians sometimes consider ethionamide for other mycobacterial diseases, although such applications have not received formal regulatory approval.

What is Ethionamide?

Ethionamide is a synthetic thioamide that functions as a bacteriostatic agent against mycobacteria. It was first introduced in the s as a structural analogue of the naturally occurring antibiotic isoniazid, with the aim of overcoming isoniazid-resistant strains. The drug is marketed globally under various brand names, including Teburic, Ethion, and Eto-M. Because the active ingredient is the same across these products, the 250 mg tablet is considered a generic formulation that can be sourced from multiple reputable manufacturers.

How Ethionamide Works

Ethionamide interferes with mycobacterial cell wall synthesis. After intracellular activation by the bacterial enzyme EthA, the drug forms a covalent adduct with InhA, an enoyl-acyl carrier protein reductase essential for the synthesis of mycolic acids. Mycolic acids are long-chain fatty acids that provide structural integrity to the mycobacterial cell envelope. By inhibiting InhA, ethionamide halts the production of these lipids, leading to a weakened cell wall and eventual bacterial growth arrest.

Key pharmacokinetic points:

• Onset of action: Clinical improvement is usually observed after 2-4 weeks of consistent therapy, reflecting the slow replication rate of Mycobacterium tuberculosis.
• Half-life: Approximately 2-3 hours, but the drug’s effect persists because the active metabolite remains bound to its target.
• Elimination: Primarily hepatic metabolism via oxidation and conjugation; renal excretion accounts for a minor fraction.

Conditions Treated with Ethionamide

The drug is used only when susceptibility testing demonstrates a likely benefit, and it is always combined with other anti-tubercular agents to prevent the emergence of further resistance.

Off-Label and Investigational Uses of Ethionamide

• Nontuberculous Mycobacterial (NTM) skin and soft-tissue infections - Small case series have reported clinical improvement when ethionamide was added to multidrug regimens for refractory NTM cutaneous disease. Evidence remains limited to observational data.
• Adjunctive therapy for chronic pulmonary sarcoidosis - A handful of pilot studies explored ethionamide’s anti-inflammatory properties, but no definitive efficacy has been demonstrated, and the approach is not endorsed by major societies.
• Experimental regimens for XDR-TB in pediatric populations - Compassionate-use protocols have incorporated ethionamide when other options were exhausted, with careful monitoring for hepatotoxicity.

These applications are not approved by the U.S. Food and Drug Administration (FDA), the European Medicines Agency (EMA), or comparable regulatory bodies. Patients should only consider off-label use under the direct supervision of a qualified healthcare professional, and the risk-benefit profile must be evaluated on an individual basis.

Is Ethionamide the Right Medication for You?

Ethionamide is appropriate for adults who:

• Have confirmed MDR-TB or XDR-TB with documented susceptibility to ethionamide.
• Require a second-line agent that can be combined with other effective drugs to construct a regimen of at least four active medications.
• Possess adequate hepatic function (baseline transaminases ≤ 2 × upper limit of normal) because the drug is metabolized in the liver.

Contraindications and cautionary scenarios include:

• Severe liver disease (e.g., cirrhosis, active hepatitis) - the risk of hepatotoxicity outweighs potential benefit.
• Known hypersensitivity to ethionamide or any thioamide class.
• Pregnancy and lactation - animal studies show teratogenic effects; the drug is classified as Pregnancy Category C, and safer alternatives are preferred.
• Pre-existing peripheral neuropathy - ethionamide can exacerbate nerve damage, especially when combined with other neurotoxic agents.

Patients with these conditions should discuss alternative treatment options with their care team.

Risks, Side Effects, and Interactions

Common

• Gastrointestinal upset (nausea, vomiting, abdominal pain) - often mitigated by taking the tablet with food.
• Loss of appetite and weight loss - monitor nutritional status during prolonged therapy.
• Mild hepatotoxicity (elevated ALT/AST) - routine liver function tests are recommended every 2-4 weeks.

Rare

• Hypothyroidism - ethionamide can interfere with thyroid hormone synthesis; periodic TSH assessment is advisable for long-term users.
• Photosensitivity - patients should avoid prolonged sun exposure and use sunscreen.

Serious

• Severe hepatotoxicity (fulminant hepatitis) - presents with jaundice, dark urine, and markedly elevated liver enzymes; immediate discontinuation and medical evaluation are required.
• Peripheral neuropathy - may manifest as tingling, numbness, or burning sensations in the extremities; dose reduction or vitamin B6 supplementation can be considered.
• Severe allergic reactions (Stevens-Johnson syndrome, toxic epidermal necrolysis) - characterized by widespread skin detachment and mucosal involvement; this is a medical emergency.

Drug-Drug Interactions

• Isoniazid, rifampicin, and other anti-TB agents - may increase hepatotoxic risk; liver monitoring is essential.
• Anticonvulsants (e.g., phenytoin, carbamazepine) - can induce hepatic enzymes, potentially lowering ethionamide plasma levels.
• Warfarin - ethionamide may potentiate anticoagulant effect; INR should be checked more frequently.

Drug-Food Interactions

• High-fat meals - can delay absorption but do not significantly alter overall exposure; taking the tablet with a light snack is acceptable.
• Alcohol - concurrent use heightens the risk of liver injury and should be avoided.

Use: Dosing, Missed Dose, Overdose

Standard dosing for adults with MDR-TB typically starts at 250 mg once daily, with the possibility of increasing to 500 mg daily (divided into two doses) based on susceptibility results, tolerability, and therapeutic drug monitoring. Treatment duration is usually 18-24 months, aligned with the overall TB regimen.

• Missed dose: If a dose is forgotten within 12 hours, take it as soon as remembered. If more than 12 hours have passed, skip the missed dose and resume the regular schedule. Do not double-dose to compensate.
• Overdose: Acute ingestion of more than 2 g may cause severe nausea, vomiting, and hepatic injury. Seek emergency medical care immediately; activated charcoal may be administered if presentation is early.

Practical administration tips

• Swallow the tablet whole with a glass of water; crushing or chewing can affect drug release.
• Avoid alcohol and limit exposure to bright sunlight while on therapy.
• Do not operate heavy machinery or drive if you experience dizziness or visual disturbances.

FAQ

• What should I do with ethionamide tablets when traveling abroad? Store the tablets in their original container, protected from heat and moisture. Carry a copy of the prescription (or a physician’s letter) in case customs officials request documentation.

• Can I take ethionamide with vitamin B6 supplements? Vitamin B6 (pyridoxine) is often prescribed alongside ethionamide to reduce the risk of peripheral neuropathy. Discuss the appropriate dose with your healthcare provider.

• How long does it take for ethionamide to appear on a drug test? Standard urine drug screens do not detect ethionamide. Specialized analytical methods would be required, and the drug is unlikely to be screened for in occupational testing.

• Are there any known differences between ethionamide tablets manufactured in the United States versus Europe? The active ingredient and dosage strength are identical, but inactive excipients (binders, fillers) may vary. Patients with specific allergies should review the full ingredient list provided by the manufacturer.

• What is the recommended storage temperature for ethionamide tablets? Store at 20-25 °C (68-77 °F) in a dry place, away from direct sunlight. Do not refrigerate or freeze the medication.

• Can ethionamide be taken with antacids? Antacids do not significantly affect ethionamide absorption, but taking them at the same time may increase gastrointestinal discomfort. Spacing them by at least one hour is advisable.

• Is it safe to use ethionamide while breastfeeding? Ethionamide is excreted in breast milk in small amounts. Because of potential infant hepatotoxicity, most guidelines recommend avoiding breastfeeding or using an alternative medication.

• How does ethionamide differ from isoniazid in terms of side-effect profile? Both drugs can cause hepatotoxicity, but ethionamide has a higher incidence of gastrointestinal upset and peripheral neuropathy, while isoniazid more commonly leads to pyridoxine-deficiency neuropathy.

• What should I do if I experience a rash while on ethionamide? A mild rash may be benign, but any skin eruption that spreads, blisters, or involves mucous membranes warrants immediate medical evaluation for possible severe hypersensitivity.

• Can I store ethionamide tablets in a bathroom cabinet? Bathrooms often experience high humidity, which can degrade the tablet’s stability. It is better to keep the medication in a cool, dry drawer or a dedicated medication box.

Glossary

Mycolic acids

Long-chain fatty acids that form a crucial component of the mycobacterial cell wall, providing resistance to chemical damage and dehydration.

Enzyme induction

The process by which a drug increases the activity of metabolic enzymes, potentially lowering the plasma concentration of co-administered medications.

Hepatotoxicity

Liver injury caused by a chemical agent, manifested by elevated liver enzymes, jaundice, or, in severe cases, liver failure.

Peripheral neuropathy

Damage to the peripheral nerves resulting in symptoms such as tingling, numbness, or pain, often dose-related with certain antimicrobials.

Buying Ethionamide from Our Online pharmacy

Ethionamide is available for purchase through our online pharmacy. We source the 250 mg tablets from licensed, audited manufacturers that meet international quality standards, ensuring the product matches the potency and purity required for MDR-TB therapy.

• Cost-effective pricing: Because we operate as a pharmacy-broker service, we can offer the generic formulation at a price close to the manufacturer’s cost, reducing the financial burden for patients who need long-term treatment.
• Verified quality: Every batch is accompanied by a certificate of analysis and is stored under controlled conditions before shipment.
• Discreet, reliable delivery: Orders are packaged in unmarked envelopes and dispatched via secure carriers. Standard international airmail typically arrives within three weeks, while express options are available for faster receipt.
• Privacy-focused service: We respect patient confidentiality; no personal health information is displayed on the exterior of the package, and all communications are encrypted.

For individuals facing limited access to ethionamide through local pharmacies or insurance formularies, our service provides a safe, affordable pathway to obtain the medication they need.

Disclaimer

The information presented about Ethionamide is intended for general educational purposes only and does not substitute professional medical advice. Treatment decisions, including any off-label applications, must be made under the supervision of a qualified healthcare provider. Readers are presumed to be responsible adults capable of evaluating health information critically. Our online pharmacy supplies Ethionamide to patients who may encounter restricted availability through conventional channels or who seek cost-effective generic alternatives. Always consult a qualified clinician before initiating, modifying, or discontinuing any medication.