Trecator SC (ethionamide) is a second-line antibacterial medication specifically formulated for the treatment of active tuberculosis (TB), particularly in cases involving drug-resistant strains such as multidrug-resistant TB (MDR-TB). It is a critical component of combination therapy, never to be used as a monotherapy, and works by inhibiting the synthesis of mycolic acids, an essential component of the Mycobacterium tuberculosis cell wall. Its use is strictly managed by healthcare professionals specializing in infectious diseases or pulmonology to ensure optimal therapeutic outcomes and minimize the development of further resistance.

Features

• Active pharmaceutical ingredient: Ethionamide 250 mg per scored tablet.
• Pharmacologic class: Second-line antituberculosis agent; thioamide derivative.
• Mechanism of action: Inhibits the synthesis of mycolic acids, essential components of the mycobacterial cell wall.
• Form: Oral film-coated tablets, allowing for flexible dosing via tablet splitting.
• Prescription status: Available only by prescription, requiring specialist oversight.

Benefits

• Targets and eliminates drug-resistant Mycobacterium tuberculosis strains, including MDR-TB, when other first-line agents are ineffective.
• Disrupts the structural integrity of the bacterial cell wall, leading to bacterial cell death and reducing the infectious load.
• Serves as a crucial component of a tailored, multi-drug regimen designed to overcome resistance and achieve sputum culture conversion.
• Oral administration facilitates both inpatient and outpatient treatment protocols, supporting long-term therapy adherence.
• Contributes to the global effort to combat complex tuberculosis infections and prevent further transmission within communities.

Common use

Trecator SC is indicated for the treatment of active pulmonary and extrapulmonary tuberculosis in conjunction with other antituberculosis agents. Its primary use is in cases where first-line drugs (e.g., isoniazid, rifampin) have failed due to bacterial resistance or are not tolerated by the patient. It is a cornerstone therapy for managing confirmed or suspected multidrug-resistant tuberculosis (MDR-TB) and is always part of a carefully constructed regimen based on drug susceptibility testing (DST) results to ensure efficacy and prevent amplification of resistance.

Dosage and direction

Dosage must be individualized based on the patient’s regimen, weight, and tolerability. It is typically administered once daily or in divided doses.

• Adults: The usual dose is 15-20 mg/kg per day, not to exceed 1 gram (1000 mg) daily. A common regimen is 250 mg to 500 mg every 12 or 24 hours.
• Children: The recommended dose is 15-20 mg/kg per day, administered in divided doses. The maximum daily dose is 1 gram.
• Administration: Tablets should be swallowed whole with a full glass of water. To minimize gastrointestinal upset, administration with food or after meals is advised, even if it slightly delays absorption. Doses should be taken at regularly spaced intervals to maintain a constant serum level.

Precautions

• Hepatotoxicity: Trecator SC has been associated with severe liver injury. Baseline liver function tests (LFTs) must be obtained before initiation and monitored frequently throughout therapy.
• Gastrointestinal Effects: Nausea, vomiting, and abdominal pain are very common. These can often be managed by taking the drug with food, but persistent symptoms should be reported.
• Endocrine Effects: Hypothyroidism has been reported. Thyroid function should be monitored, especially in patients with pre-existing thyroid disorders.
• Neurological Effects: Peripheral neuropathy and optic neuritis are possible. Concomitant administration of pyridoxine (Vitamin B6) is strongly recommended to help mitigate this risk.
• Psychiatric Effects: Use with caution in patients with a history of psychiatric disorders, as mental depression and other disturbances have been observed.
• Pregnancy and Lactation: Use during pregnancy only if the potential benefit justifies the potential risk to the fetus. Ethionamide is excreted in breast milk; a decision should be made whether to discontinue nursing or discontinue the drug.

Contraindications

Trecator SC is contraindicated in patients with:

• Severe hypersensitivity to ethionamide or any component of the formulation.
• Severe hepatic impairment or active liver disease.
• A history of severe psychiatric reactions to the drug.

Possible side effect

A wide range of side effects is possible, necessitating close patient monitoring.

• Very Common (>10%): Anorexia, nausea, vomiting, metallic taste, abdominal pain, excessive salivation, diarrhea.
• Common (1-10%): Rash, dizziness, drowsiness, headache, postural hypotension, gynecomastia, impotence, menstrual irregularities, thrombocytopenia.
• Uncommon (<1%): Hepatitis, jaundice, blurred vision/diplopia, optic neuritis, peripheral neuropathy, pellagra-like syndrome, hypothyroidism, psychiatric disturbances (including depression, psychosis), photosensitivity, acne, alopecia.

Drug interaction

Trecator SC interacts with several other medications, which must be carefully managed.

• Cycloserine: Concurrent use may increase the risk of central nervous system (CNS) toxicity such as dizziness or seizures.
• Isoniazid: May increase the risk of hepatotoxicity and neurotoxicity.
• Rifampin: Can increase the metabolism of ethionamide, potentially reducing its serum levels and efficacy.
• Oral Hypoglycemic Agents: Ethionamide may potentiate their effects, increasing the risk of hypoglycemia.
• Tyramine-containing foods: While less pronounced than with some other drugs, a tyramine reaction (hypertensive crisis) is theoretically possible. Patients should be cautioned about consuming aged cheeses, cured meats, and tap beer.
• Alcohol: Concurrent use can increase the risk of hepatotoxicity and CNS effects.

Missed dose

If a dose is missed, it should be taken as soon as it is remembered. However, if it is almost time for the next scheduled dose, the missed dose should be skipped. The patient should never take a double dose to make up for a missed one. Maintaining a consistent dosing schedule is critical for therapeutic efficacy and to prevent resistance. Patients should inform their healthcare provider about any missed doses.

Overdose

Symptoms of overdose are primarily extensions of its known adverse effects, particularly severe nausea, vomiting, neurological symptoms (dizziness, seizures), and potential hepatotoxicity. There is no specific antidote for ethionamide overdose. Management is supportive and symptomatic, including gastric lavage if ingestion was recent, maintaining hydration, and monitoring and supporting vital functions. In case of suspected overdose, immediate medical attention is required.

Storage

• Store at controlled room temperature, 20°C to 25°C (68°F to 77°F).
• Protect from light and moisture. Keep the bottle tightly closed.
• Keep out of reach of children and pets.
• Do not flush medication down the toilet or pour it into a drain. Dispose of unused medication via a official take-back program or a pharmacy.

Disclaimer

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or medication. Never disregard professional medical advice or delay in seeking it because of something you have read here. The content has been compiled from various resources but may not be exhaustive or fully updated.

Reviews

• Infectious Disease Specialist, UK: “An irreplaceable, if challenging, agent in our MDR-TB arsenal. Gastrointestinal side effects are almost universal but can be managed. Its efficacy in combination therapy is well-documented. Mandatory pyridoxine co-administration and vigilant LFT monitoring are non-negotiable.”
• Pulmonologist, India: “We use Trecator SC extensively in our DOTS-Plus programs for complex cases. While patient tolerance is a significant hurdle, its role in achieving culture conversion in resistant strains is undeniable. It demands a committed physician and a compliant patient.”
• Clinical Pharmacist, US: “Managing Trecator SC therapy is a exercise in proactive toxicity management. The drug interaction profile is significant, particularly with other second-line TB drugs. Our focus is on patient education regarding side effects and the absolute necessity of adherence to the entire regimen.”
• Patient (Completed treatment): “The side effects were rough, especially the nausea and the metallic taste that made everything taste like coins. But my medical team was supportive, and taking it with food helped. Knowing it was a key drug fighting the resistant bug kept me going. I’m now TB-free.”