Common Loss of appetite, Nausea, Vomiting, Gastric irritation, Orthostatic hypotension (sudden lowering of blood pressure on standing), Weakness, Depression, Sleepiness.

Expert advice for Ethiobin Tablet

You should always take ethionamide in combination with other anti-tubercular drugs as its use alone in the treatment results in the rapid development of drug-resistant tuberculosis. 
Always adhere to the drug regimen for the full duration of treatment as non-adherence to prescribed treatment can result in treatment failure and in the development of drug-resistant tuberculosis, which can be life-threatening and lead to other serious health risks. 
Tell your doctor if you have diabetes, liver problems, or vision problems.
You may be monitored with blood sugar, liver function, vision and thyroid function tests while on treatment with ethionamide.
Tell your doctor if you are pregnant or planning to become pregnant or are breastfeeding.
Ethionamide is not recommended in children below 12 years unless the organisms are found to be definitely resistant to primary therapy.

Q. What is Ethiobin used for?
Ethiobin is used in combination with other medicines for the treatment of active tuberculosis (infectious disease caused by Mycobacterium tuberculosis).