Common uses of Ethionamide in tuberculosis treatment
Ethionamide is an antimycobacterial agent used primarily as part of combination therapy for tuberculosis (TB), especially when the infecting Mycobacterium tuberculosis strain shows resistance to first‑line medications (e.g., isoniazid, rifampin) or when patients cannot tolerate those drugs. It inhibits the synthesis of mycolic acids in the bacterial cell wall, undermining the organism’s structural integrity and survival.
Because monotherapy rapidly selects for resistant bacteria, ethionamide is never used alone. It is typically combined with two or more active agents chosen from other second‑line classes (e.g., fluoroquinolones, cycloserine, clofazimine, bedaquiline, linezolid, PAS), guided by culture and susceptibility testing whenever possible. Infectious disease or TB specialists tailor regimens to disease site, resistance profile, comorbidities, and drug tolerance.
Ethionamide may be used for pulmonary TB and extrapulmonary TB (e.g., lymph node, bone, CNS) when indicated. Treatment duration for drug‑resistant TB is long—often 6 to 24 months, depending on response, regimen, and guidelines. Close monitoring is essential to balance efficacy with safety, given the drug’s gastrointestinal, hepatic, neurologic, and endocrine adverse‑effect profile.
Although ethionamide is an important tool for multidrug‑resistant TB (MDR‑TB), new agents and shorter regimens are increasingly recommended where available. Your TB team will weigh benefits and risks of ethionamide versus alternatives and may adjust therapy as culture results and clinical progress evolve.
Ethionamide dosage and directions
Dosing is individualized and should be set by a clinician experienced in TB care. General adult dosing guidance: initiate 250 mg once daily after food to improve tolerance, then titrate upward by 250 mg every 3 to 7 days as tolerated, dividing the dose twice daily to lessen gastrointestinal effects. Usual total daily dose is 500 to 750 mg/day in 2–3 divided doses. The maximum is 1,000 mg/day. Pediatric dosing is typically 15–20 mg/kg/day (in 2–3 divided doses), not to exceed 1,000 mg/day.
Administration tips: take with meals or milk to reduce nausea, and consider bedtime dosing of the larger split if daytime intolerance occurs. Many clinicians co‑prescribe pyridoxine (vitamin B6) 25–50 mg/day to lower the risk of peripheral neuropathy, especially if other neuropathic agents (like isoniazid or cycloserine) are included.
Ethionamide is only one component of a multidrug regimen. Adherence to the full, prescribed combination is vital; stopping any single agent prematurely can foster additional resistance and treatment failure. Directly observed therapy (DOT) or digital adherence technologies may be used to support consistent dosing. If severe adverse effects occur, do not stop abruptly without contacting your TB team; targeted adjustments and supportive care can often restore tolerability.
Baseline and periodic laboratory monitoring, including hepatic panels and thyroid function tests, are often recommended throughout therapy, particularly when higher doses are required or when combined with other hepatotoxic or endocrine‑active agents.
Ethionamide precautions
Liver health: Ethionamide can cause hepatocellular injury. Patients with pre‑existing liver disease, viral hepatitis, alcohol use disorder, or concomitant hepatotoxic medications require careful risk–benefit assessment, baseline LFTs, and frequent monitoring. Watch for fatigue, right‑upper‑quadrant pain, dark urine, or jaundice.
Neurologic effects: Headache, dizziness, and peripheral neuropathy can occur, especially with co‑administered neurotoxic agents. Vitamin B6 is routinely used to mitigate risk. Report numbness, tingling, burning pain, or gait changes promptly.
Endocrine/thyroid: Hypothyroidism is a recognized effect, with higher risk when ethionamide is combined with PAS or pyrazinamide. Clinicians may monitor TSH periodically and treat thyroid dysfunction if it develops. Symptoms include fatigue, cold intolerance, weight gain, and hair thinning.
Gastrointestinal intolerance: Nausea, vomiting, abdominal pain, and metallic taste are common early in therapy. Taking doses with food, splitting doses, slow titration, and antiemetics can help. Persistent inability to keep doses down warrants reassessment.
Psychiatric considerations: Depression, irritability, and sleep disturbances are reported. Patients with a history of mood disorders require close follow‑up and should report mood changes, anxiety, or suicidal thoughts immediately.
Pregnancy and lactation: Data in pregnancy are limited; ethionamide has shown teratogenicity in animals and is generally avoided during pregnancy if alternatives are available. When treatment is essential, specialist consultation is mandatory. Breastfeeding considerations should be individualized; discuss risks and benefits with your TB specialist.
Diabetes and nutrition: Ethionamide can affect glucose control and appetite. Monitor blood sugars closely and maintain adequate nutrition; dietitian support may be helpful during prolonged therapy.
Alcohol: Avoid alcohol due to increased risk of hepatotoxicity and potential disulfiram‑like reactions (flushing, nausea, vomiting).
Important: Information here is educational and not a substitute for individualized medical advice. TB regimens should be managed by clinicians experienced in mycobacterial disease.
Ethionamide contraindications
Do not use ethionamide if you have a known hypersensitivity to ethionamide or any formulation component.
Use is generally contraindicated or requires extreme caution in severe hepatic impairment due to the risk of hepatotoxicity. Significant baseline psychiatric illness, uncontrolled hypothyroidism, severe gastrointestinal disease with intractable vomiting, or heavy alcohol use may preclude safe use or necessitate alternative strategies. Always evaluate risks in consultation with a TB specialist.
Possible side effects of Ethionamide
Common: Nausea, vomiting, abdominal discomfort, loss of appetite, heartburn, metallic or bitter taste, excessive salivation, dizziness, and headaches. These often improve with food co‑administration, divided dosing, slower titration, or antiemetic support.
Neurologic: Peripheral neuropathy (numbness, tingling, burning), weakness, tremor, and, rarely, seizures—especially when combined with other neurotoxic drugs. Prophylactic pyridoxine is commonly used, and prompt reporting of symptoms allows early management.
Hepatic: Asymptomatic LFT elevations are possible; clinical hepatitis is less common but can be serious. Warning signs include fatigue, dark urine, pruritus, jaundice, and right‑upper‑quadrant pain.
Endocrine: Hypothyroidism can develop, particularly with concurrent PAS or pyrazinamide. Symptoms include fatigue, cold intolerance, dry skin, constipation, and weight gain; periodic TSH checks are prudent.
Psychiatric: Depression, anxiety, mood lability, insomnia, and, rarely, psychosis have been reported. New or worsening psychiatric symptoms require immediate clinical attention.
Dermatologic/other: Acneiform eruptions, rash, photosensitivity, gynecomastia, menstrual irregularities, and changes in blood glucose may occur. Severe cutaneous reactions are rare but serious; stop the drug and seek urgent care if you develop widespread rash, blistering, mucosal involvement, or facial swelling.
Seek urgent medical help for severe abdominal pain, persistent vomiting, confusion, severe weakness, jaundice, chest pain, shortness of breath, or signs of an allergic reaction (hives, swelling of face/lips/tongue, difficulty breathing).
Ethionamide drug interactions
Hepatotoxic combinations: Co‑administration with other hepatotoxic agents (e.g., high‑dose isoniazid, rifampin, pyrazinamide, certain azoles, or chronic acetaminophen use) can raise liver risk. Clinicians often stagger initiation, intensify monitoring, or adjust doses.
Neurotoxic combinations: Cycloserine, isoniazid, and linezolid can increase the risk of neuropathy or CNS effects when used with ethionamide. Pyridoxine supplementation and close symptom monitoring are advised.
Endocrine interactions: Concurrent PAS or pyrazinamide increases the likelihood of hypothyroidism; routine TSH checks may be recommended.
Alcohol and disulfiram: Alcohol can potentiate nausea/vomiting and hepatotoxicity and may cause disulfiram‑like reactions. Caution is also warranted with disulfiram due to potential CNS effects.
Diabetes medications: Ethionamide may affect glycemic control; monitor blood glucose and adjust antidiabetic therapy as needed.
Because multidrug TB regimens are complex, always provide your TB team with a complete list of prescription drugs, OTC medicines, vitamins, and herbal supplements (e.g., St. John’s wort) to avoid unexpected interactions and to optimize efficacy and safety.
Missed dose of Ethionamide
If you miss a dose, take it as soon as you remember unless it is close to the time for your next dose. If it is near the next scheduled dose, skip the missed dose and resume your regular schedule. Do not double up to “catch up.” Consistency is critical in TB therapy; alert your care team if you are missing doses due to side effects so they can help with supportive measures or regimen adjustments.
Ethionamide overdose
Suspected overdose may present with severe nausea/vomiting, dizziness, confusion, seizures, profound weakness, or signs of liver injury. This is a medical emergency. Call 911 (or your local emergency number) and, if in the United States, contact Poison Control at 1‑800‑222‑1222 for immediate guidance. Supportive care, airway protection, seizure control, and close monitoring are standard; bring the medication container to the emergency department if safe to do so.
Storage of Ethionamide
Store at controlled room temperature (generally 20–25°C/68–77°F), protected from moisture and excessive heat. Keep tablets in their original, tightly closed container with desiccant if provided. Do not store in bathrooms. Keep out of reach of children and pets. Properly discard expired or unused medication—ask your pharmacist about take‑back programs.
U.S. sale and prescription policy: safe, legal access and HealthSouth Rehabilitation Hospital of Las Vegas
Ethionamide is a prescription‑only medication in the United States. It should be used exclusively under the supervision of clinicians experienced in TB care, and it is not lawful to purchase or import it for personal use without a valid prescription. If you see offers claiming “no prescription needed,” treat them as red flags for safety and legal concerns.
We recognize that people search for phrases like “buy Ethionamide without prescription.” In the U.S., the safe, legal path requires clinician authorization. HealthSouth Rehabilitation Hospital of Las Vegas provides a compliant, structured solution by connecting patients with licensed healthcare professionals for telehealth evaluation; when medically appropriate, a legitimate electronic prescription is issued and filled through our pharmacy. This means you are not asked to bypass medical oversight or handle a paper script—care remains fully within U.S. regulatory standards.
Benefits of this integrated model include coordinated therapy with your TB team, verification of drug supply quality, clear counseling on dosing and side effects, ongoing monitoring support, and secure, discreet delivery. To begin, consult your TB specialist or contact HealthSouth Rehabilitation Hospital of Las Vegas to learn how we coordinate with clinicians and public health programs to ensure access that is both patient‑centered and compliant with U.S. law.
