How often should the drug be discontinued during long-term treatment with cycloserine, which is more in line with safety regulations?

Cycloserine is an oral anti-tuberculosis drug mainly used to treat drug-resistant tuberculosis (MDR-TB) and some recurrent tuberculosis infections. As an antibiotic with a structure similar to amino acids, it prevents the growth of Mycobacterium tuberculosis by inhibiting D-alanyl-D-alanine synthase in bacterial cell wall synthesis. Cycloserine is often used in combination with other anti-tuberculosis drugs in long-term treatment. Because it may cause central nervous system side effects, such as anxiety, depression, insomnia, or epileptic seizures, the arrangement of discontinuation and follow-up is crucial during long-term treatment.

In clinical practice, cycloserine is mostly taken once a day or in divided doses, and the course of treatment can last from 6 months to 18 months, depending on the type of drug-resistant strains, patient tolerance and combination regimen. During treatment, regular follow-up visits are generally recommended rather than arbitrary discontinuation of medication. In routine safety regulations, drug withdrawal arrangements are mostly based on blood drug concentration monitoring and the occurrence of patients’ neurological symptoms. Studies have shown that when the blood drug concentration is maintained within a safe range (usually 15–35 μg/mL) and the patient develops neuropsychiatric symptoms, short-term drug discontinuation or dose adjustment can be considered, and then treatment can be continued under the guidance of a doctor.

Specific to the frequency of drug discontinuation, cycloserine does not recommend regular "preventive drug discontinuation", but should be dynamically adjusted based on the patient's individual response. For example, if a patient develops mild central nervous system symptoms, the doctor may recommend a 1-3 day break to observe symptom improvement, and then gradually resume the original dose; if severe neuropsychiatric symptoms occur, the drug needs to be discontinued immediately and symptomatic treatment must be taken, and then restarted at a low dose after the symptoms are relieved. Long-term regular blood drug concentration testing and mental and neurological status assessment are core measures to ensure drug safety.
Generally speaking, during long-term treatment with cycloserine, drug discontinuation should be based on individualized assessment rather than fixed periodic drug discontinuation. Safety regulations require doctors to flexibly adjust the dosage and withdrawal time based on blood drug concentration, patient tolerance and central nervous system symptoms to ensure that the anti-tuberculosis efficacy is achieved while minimizing the risk of neurological side effects. Strict compliance with the follow-up and monitoring plan is key to long-term safe medication use.
Reference: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7159050/