Hello dear Understand your concern. Isoniazid can cause nerve problem and twitches. But i think it is not occur after 30 years. I think some other reasons behind that like vitamin deficiency, neurological disorder, trauma, viral disease. Please note the side effects of isoniazid: More common Clumsiness or unsteadiness dark urine loss of appetite nausea or vomiting numbness, tingling, burning, or pain in hands and feet unusual tiredness or weakness yellow eyes or skin Rare Blurred vision or loss of vision, with or without eye pain convulsions (seizures) fever and sore throat joint pain mental depression mood or other mental changes skin rash unusual bleeding or bruising Following are the side effects of disulfiram: Drowsiness, sweatiness, halitosis, alteration in taste, impotence, dizziness and headache. It may be permanent in some case. So it may be due to dislufiram.. Please consult the specialist of neurology. Hope this may help you. Best regards Dr. Sagar