Second-line antituberculosis drug exposure thresholds predictive of adverse events in multidrug-resistant tuberculosis treatment.

OBJECTIVES: This study aimed to investigate the association between drug exposure and adverse events (AEs) during the standardized multidrug-resistant tuberculosis (MDR-TB) treatment, as well as to identify predictive drug exposure thresholds. METHODS: We conducted a prospective, observational multicenter study among participants receiving standardized MDR-TB treatment between 2016 and 2019 in China. AEs were monitored throughout the treatment and their relationships to drug exposure (e.g., the area under the drug concentration-time curve from 0 to 24 h, AUC0-24 h) were analyzed. The thresholds of pharmacokinetic predictors of observed AEs were identified by boosted classification and regression tree (CART) and further evaluated by external validation. RESULTS: Of 197 study participants, 124 (62.9%) had at least one AE, and 15 (7.6%) experienced serious AEs. The association between drug exposure and AEs was observed including bedaquiline, its metabolite M2, moxifloxacin and QTcF prolongation (QTcF >450 ms), linezolid and mitochondrial toxicity, cycloserine and psychiatric AEs. The CART-derived thresholds of AUC0-24 h predictive of the respective AEs were 3.2 mg·h/l (bedaquiline M2); 49.3 mg·h/l (moxifloxacin); 119.3 mg·h/l (linezolid); 718.7 mg·h/l (cycloserine). CONCLUSIONS: This study demonstrated the drug exposure thresholds predictive of AEs for key drugs against MDR-TB treatment. Using the derived thresholds will provide the knowledge base for further randomized clinical trials of dose adjustment to minimize the risk of AEs.

D-Cycloserine-Induced Seizure Activity in the Emergency Department: A Case Report.

D-cycloserine (DCS) is an anti-tuberculosis medication that has been utilized for years for drug-resistant tuberculosis. DCS works via a centrally acting mechanism which can cause neurotoxic adverse effects which has limited its use. This centrally acting mechanism also allows for DCS to be utilized for various neuropsychiatric purposes. Our patient was on high-dose DCS for autism spectrum disorder and presented to the emergency department (ED) with a seizure. The seizure episode was managed with both anti-epileptics and pyridoxine. With increasing novel use of this older medication, it is imperative for ED clinicians to be aware of the different management strategies that may be required when a patient presents with a neurotoxic effect, specifically seizures, secondary to DCS.

Neuropsychiatric toxicity and cycloserine concentrations during treatment for multidrug-resistant tuberculosis.

BACKGROUND: Cycloserine, or its structural analogue terizidone, has been associated with neuropsychiatric toxicity (psychosis, depression, and neuropathy). Prospective clinical data on the incidence of and risk factors for neuropsychiatric toxicity in TB patients treated with cycloserine are limited. METHODS: A prospective evaluation of neuropsychiatric toxicity was performed using validated screening tools in patients with multidrug-resistant tuberculosis treated with terizidone. Cox proportional hazard modelling was performed to explore the effects of clinical variables and measures of cycloserine pharmacokinetics in plasma. RESULTS: A total 144 participants were recruited: 86 were male and 58 were female; their median age was 35.7 years and 91 (63%) were HIV-infected. Fifty-five (38%) participants developed at least one neuropsychiatric event (30 cases per 100 person-months): 50 (35%) neuropathy, 14 (10%) depression, and 11 (8%) psychosis. Neuropathy was independently associated with cycloserine clearance ((adjusted hazard ratio 0.34 (aHR), P = 0.03)) and high-dose pyridoxine (200 mg vs 150 mg daily, aHR: 2.79, P = 0.01). CONCLUSIONS: A high incidence of early neuropsychiatric toxicity was observed in this cohort of patients treated with terizidone. Cycloserine clearance and higher doses of pyridoxine are associated with incident or worsening peripheral neuropathy.

The effectiveness and adverse effects of D-cycloserine compared with placebo on social and communication skills in individuals with autism spectrum disorder.

BACKGROUND: Symptoms of autism spectrum disorder (ASD) have been associated, in part, with the dysfunction of N-methyl-D-aspartate (NMDA) glutamate receptors at excitatory synapses and glutamate abnormalities. Medications related to glutamatergic neurotransmission, such as D-cycloserine - which is a partial agonist of the NMDA glutamate receptor - are potential treatment options for the core features of ASD. However, the potential effect of D-cycloserine on the social and communication skills deficits of individuals with ASD has not been thoroughly explored and no systematic reviews of the evidence have been conducted. OBJECTIVES: To assess the efficacy and adverse effects of D-cycloserine compared with placebo for social and communication skills in individuals with ASD. SEARCH METHODS: In November 2020, we searched CENTRAL, MEDLINE, Embase, six other databases and two trials registers. We also searched the reference lists of relevant publications and contacted the authors of the included study, Minshawi 2016, to identify any additional studies. In addition, we contacted pharmaceutical companies, searched manufacturers' websites and sources of reports of adverse events.  SELECTION CRITERIA: All randomised controlled trials (RCTs) of any duration and dose of D-cycloserine, with or without adjunct treatment, compared to placebo in individuals with ASD. DATA COLLECTION AND ANALYSIS: Two review authors independently selected studies for inclusion, extracted relevant data, assessed the risk of bias, graded the certainty of the evidence using the GRADE approach, and analysed and evaluated the data. We provide a narrative report of the findings as only one study is included in this review. MAIN RESULTS: We included a single RCT (Minshawi 2016) funded by the United States Department of Defense. It was conducted at two sites in the USA: Indiana University School of Medicine and Cincinnati Children's Hospital Medical Centre. In the included study, 67 children with ASD aged between 5 and 11 years were randomised to receive either 10 weeks (10 doses) of (50 mg) D-cycloserine plus social skills training, or placebo plus social skills training. Randomisation was carried out 1:1 between D-cycloserine and placebo arms, and outcome measures were recorded at one-week post-treatment. The 'risk of bias' assessment for the included study was low for five domains and unclear for two domains. The study (67 participants) reported low certainty evidence of little to no difference between the two groups for all outcomes measured at one week post-treatment: social interaction impairment (mean difference (MD) 3.61 (assessed with the Social Responsiveness Scale), 95% confidence interval (CI) -5.60 to 12.82); social communication impairment (MD -1.08 (measured using the inappropriate speech subscale of the Aberrant Behavior Checklist (ABC)), 95% CI -2.34 to 0.18); restricted, repetitive, stereotyped patterns of behaviour (MD 0.12 (measured by the ABC stereotypy subscale), 95% CI -1.71 to 1.95); serious adverse events (risk ratio (RR) 1.11, 95% CI 0.94 to 1.31); non-core symptoms of ASD (RR 0.97 (measured by the Clinical Global Impression-Improvement scale), 95% CI 0.49 to 1.93); and tolerability of D-cycloserine (RR 0.32 (assessed by the number of dropouts), 95% CI 0.01 to 7.68).  AUTHORS' CONCLUSIONS: We are unable to conclude with certainty whether D-cycloserine is effective for individuals with ASD. This review included low certainty data from only one study with methodological issues and imprecision. The added value of this review compared to the included study is we assessed the risk of bias and evaluated the certainty of evidence using the GRADE approach. Moreover, if we find new trials in future updates of this review, we could potentially pool the data, which may either strengthen or decrease the evidence for our findings.

Adverse Events Associated With New Injectable-Free Multidrug-Resistant Tuberculosis Drug Regimens / Efectos adversos asociados a los nuevos tratamientos farmacológicos sin inyectables contra la tuberculosis multirresistente

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Treatment Outcomes and Adverse Drug Effects of Ethambutol, Cycloserine, and Terizidone for the Treatment of Multidrug-Resistant Tuberculosis in South Africa.

Treatment outcomes among multidrug-resistant tuberculosis (MDR-TB) patients receiving ethambutol, cycloserine, or terizidone as part of a standardized regimen were compared, determining occurrence of serious adverse drug events (SADEs). Newly diagnosed adult MDR-TB patients were enrolled between 2000 and 2004, receiving a standardized multidrug regimen for 18 to 24 months, including ethambutol, cycloserine, or terizidone. Cycloserine and terizidone were recorded individually. SADEs and factors associated with culture conversion and unfavorable treatment outcomes (default, death, treatment failure) were determined. Of 858 patients, 435 (51%) received ethambutol, 278 (32%) received cycloserine, and 145 (17%) received terizidone. Demographic and baseline clinical data were comparable. Successful treatment occurred in 56%, significantly more in patients receiving cycloserine (60%) and terizidone (62%) than in those receiving ethambutol (52% [P = 0.03]). Defaults rates were 30% in ethambutol patients versus 15% and 11% for cycloserine and terizidone patients, respectively. Terizidone was associated with fewer unfavorable outcomes (adjusted odds ratio [AOR], 0.4; P = 0.008; 95% confidence interval [CI], 0.2 to 0.8). Patients receiving cycloserine were more likely to achieve culture conversion than those receiving ethambutol or terizidone (AOR, 2.2; P = 0.02; 95% CI, 1.12 to 4.38). Failure to convert increased the odds of unfavorable outcomes (AOR, 23.7; P < 0.001; 95% CI, 13 to 44). SADEs were reported in two patients receiving ethambutol, seven patients receiving cycloserine, and three receiving terizidone (P = 0.05). Ethambutol was associated with high culture conversion and default rates. Cycloserine achieved higher culture conversion rates than terizidone. Fewer patients on terizidone experienced SADEs, with lower default rates. The differences that we observed between cycloserine and terizidone require further elucidation.

Effect of D-Cycloserine on the Effect of Concentrated Exposure and Response Prevention in Difficult-to-Treat Obsessive-Compulsive Disorder: A Randomized Clinical Trial.

Importance: Evidence is lacking for viable treatment options for patients with difficult-to-treat obsessive-compulsive disorder (OCD). It has been suggested that D-cycloserine (DCS) could potentiate the effect of exposure and response prevention (ERP) treatment, but the hypothesis has not been tested among patients with difficult-to-treat OCD. Objective: To evaluate whether DCS potentiates the effect of concentrated ERP among patients with difficult-to-treat OCD. Design, Setting, and Participants: The study was a randomized placebo-controlled triple-masked study with a 12-month follow-up. Participants were adult outpatients with difficult-to-treat OCD. A total of 220 potential participants were referred, of whom 36 did not meet inclusion criteria and 21 declined to participate. Patients had either relapsed after (n = 100) or not responded to (n = 63) previous ERP treatment. A total of 9 specialized OCD teams within the public health care system in Norway participated, giving national coverage. An expert team of therapists from the coordinating site delivered treatment. Inclusion of patients started in January 2016 and ended in August 2017. Data analysis was conducted February to September 2019. Interventions: All patients received individual, concentrated ERP treatment delivered during 4 consecutive days in a group setting (the Bergen 4-day treatment format) combined with 100 mg DCS, 250 mg DCS, or placebo. Main outcomes and Measures: Change in symptoms of OCD and change in diagnostic status. Secondary outcomes measures included self-reported symptoms of OCD, anxiety, depression, and quality of life. Results: The total sample of 163 patients had a mean (SD) age of 34.5 (10.9) years, and most were women (117 [71.8%]). They had experienced OCD for a mean (SD) of 16.2 (10.2) years. A total of 65 patients (39.9%) were randomized to receive 100 mg DCS, 67 (41.1%) to 250 mg of DCS, and 31 (19.0%) to placebo. Overall, 91 (56.5%) achieved remission at posttreatment, while 70 (47.9%) did so at the 12-month follow-up. There was no significant difference in remission rates among groups. There was a significant reduction in symptoms at 12 months, and within-group effect sizes ranged from 3.01 (95% CI, 2.38-3.63) for the group receiving 250 mg DCS to 3.49 (95% CI, 2.78-4.18) for the group receiving 100 mg DCS (all P < .001). However, there was no significant effect of treatment group compared with placebo in obsessive-compulsive symptoms (250 mg group at posttreatment: d = 0.33; 95% CI, -0.10 to 0.76; 100 mg group at posttreatment: d = 0.36; 95% CI, -0.08 to 0.79), symptoms of depression and anxiety (eg, Patient Health Questionnaire-9 score among 250 mg group at 12-month follow-up: d = 0.30; 95% CI, -0.17 to 0.76; Generalized Anxiety Disorder-7 score among 100 mg group at 12-month follow-up: d = 0.27; 95% CI, -0.19 to 0.73), and well-being (250 mg group: d = 0.10; 95% CI, -0.42 to 0.63; 100 mg group: d = 0.34; 95% CI, -0.19 to 0.86). No serious adverse effects were reported. Conclusions and Relevance: In this study, DCS did not potentiate ERP treatment effect, but concentrated ERP treatment was associated with improvement. Trial Registration: ClinicalTrials.gov identifier: NCT02656342.

Irreversible neuropathy in extremely-drug resistant tuberculosis: An unfortunate clinical conundrum.

Drug-resistant tuberculosis is an increasing healthcare challenge. Drug regimen building demands the use of different therapeutic groups, many of which harbor neurotoxicity as a side-effect, whether central or peripheral. Peripheral neuropathy is a major concern as it tends to be severe and usually irreversible. Anti-tubercular drugs that may contribute to peripheral neuropathy include INH, ethambutol, linezolid, cycloserine and para-amino salicylic acid. This potential adverse effect must be balanced against the intrinsically grave prognosis that drug resistant tuberculosis harbors. We present such a clinically challenging case of a 25 years-old female with extremely drug resistant tuberculosis whose treatment necessitated the use of several neurotoxic anti-tubercular drugs, leading to severe sensory peripheral neuropathy who did not improve despite the withdrawal of culprit drugs. She developed positive and negative sensory symptoms in both lower limbs. Nerve conduction studies were suggestive of sensory neuropathy affecting both lower limbs. Alternate causes of peripheral neuropathy including HIV, vasculitis, B12 deficiency and diabetes were ruled out. Despite drug withdrawal, the patient did not improve significantly. This case emphasizes the irreversibility of anti-tubercular therapy-induced peripheral neuropathy, demanding more rigorous clinical screening for the same while managing such patients.

Shedding Light on the Transcriptomic Dark Matter in Biological Psychiatry: Role of Long Noncoding RNAs in D-cycloserine-Induced Fear Extinction in Posttraumatic Stress Disorder.

Biological psychiatry scholarship on posttraumatic stress disorder (PTSD) is making strides with new omics technologies. In this context, there is growing recognition that noncoding RNAs are vital for the regulation of gene and protein expression. Long noncoding RNAs (lncRNAs) can modulate splicing, influence RNA editing, messenger RNA (mRNA) stability, translation activation, and microRNA-mRNA interactions, are highly abundant in the brain, and have been implicated in neurodevelopmental disorders. The largest subclass of lncRNAs is long intergenic noncoding RNAs (lincRNAs). We report on lincRNAs and their predicted mRNA targets associated with fear extinction induced by co-administration of D-cycloserine and behavioral fear extinction in a PTSD animal model. Forty-three differentially expressed lincRNAs and 190 differentially expressed mRNAs were found to be associated with fear extinction. Eight lincRNAs were predicted to interact with and regulate 108 of these mRNAs, while seven lincRNAs were predicted to interact with 22 of their pre-mRNA transcripts. Based on the functions of their target mRNAs, we inferred that these lincRNAs bind to nucleotides, ribonucleotides, and proteins; subsequently influence nervous system development, morphology, and immune system functioning; and could be associated with nervous system and mental health disorders. We found the quantitative trait loci that overlapped with fear extinction-related lincRNAs included traits such as serum corticosterone level, neuroinflammation, anxiety, stress, and despair-related responses. To the best of our knowledge, this is the first study to identify lincRNAs and their RNA targets with a putative role in transcriptional regulation during fear extinction in the context of an animal model of PTSD.

Neuropsychiatric reactions induced by cycloserine in the treatment of multidrug-resistant tuberculosis: what an Indian female patient tells us.

Multidrug-resistant tuberculosis continues to be a public health crisis. Urgent action is required to improve the coverage and quality of diagnosis, treatment and care for people affected by drug-resistant tuberculosis. To implement tuberculosis control, in 2018, WHO recommended cycloserine as one of the Group B drugs. Following this recommendation, cycloserine should be generally included in the starting line-up in the longer regimen for the treatment of multidrug-resistant tuberculosis. However, neurological toxicity associated with this drug concerns clinicians and limits its use. In this paper, we present a case of a 48-year-old woman with a diagnosis of multidrug-resistant tuberculosis treated with cycloserine, who developed psychiatric adverse events after 3 months of administration. This case shows the need for close psychiatric follow-up to promptly detect adverse events in patients receiving regimens for multi-drug resistant tuberculosis.

Cycloserine Induced Suicidal Tendencies and Kanamycin Induced Ototoxicity in Indian MDR-TB Patient: A Case Report.

INTRODUCTION: Cycloserine and Kanamycin are approved for treatment of multidrug-resistant tuberculosis with good tolerability in Tuberculosis patients and have various labeled adverse reactions but the neuropsychiatric adverse drug reactions with cycloserine are rarely explained. CASE REPORT: We present a case report on Cycloserine induced Suicidal tendencies and Kanamycin induced decrease in hearing sensation in Indian MDR-TB patient. A 55-year-old male patient who was diagnosed with MDR-TB was prescribed with category IV anti-tubercular therapy. Within one month of initiation of therapy, he developed repeated suicidal thoughts, joint pain, restlessness, depression, constipation, insomnia, tinnitus and a decrease in hearing sensation. RESULTS AND DISCUSSION: Cycloserine and kanamycin were closely associated with suicidal tendency and tinnitus followed by a decrease in hearing sensations respectively. On causality assessment using WHO-UMC Causality assessment scale, Adverse Drug Reaction with Cycloserine was found to be certain and for kanamycin, ADR was found to be possible. CONCLUSION: Early management of such fatal ADR can improve the compliance, thus preventing the relapse of infection as well as improving therapeutic outcome in Tuberculosis patients.

A randomized placebo-controlled pilot study of the efficacy and safety of D-cycloserine in people with chronic back pain.

BACKGROUND: Few effective pharmacological treatment options exist for chronic back pain, the leading cause of disability in the US, and all are associated with significant adverse effects. OBJECTIVE: To determine the efficacy and safety of D-cycloserine, a partial agonist to the N-methyl-D-aspartate receptor, in the treatment of chronic low back pain. METHODS: A total of 41 participants with chronic back pain who met all inclusion and exclusion criteria were enrolled in a double-blind, placebo-controlled randomized pilot trial of D-cycloserine. Treatment was administered orally for six weeks at escalating daily doses of 100 mg, 200 mg, and 400 mg, each for two weeks. The primary outcome measure was back pain intensity using the Numeric Rating Scale (0-10). Secondary measures were back pain-related questionnaires: McGill Pain Questionnaire short form, painDETECT, PANAS, and BDI. The pre-specified analysis was a two-way repeated measures analysis of variance. RESULTS: A treatment difference was observed between groups treated with D-cycloserine and placebo at six weeks of 1.05 ± 3.1 units on the Numeric Rating Scale, with an effect size of 0.4 and p = 0.14. This trend of better chronic back pain relief with D-cycloserine was also observed in the secondary measures. No safety issues were seen. CONCLUSION: The difference in mean pain between the D-cycloserine and placebo groups did not reach statistical significance. However, a clinically meaningful effect size in the magnitude of pain relief was observed with a consistent pattern across multiple outcome measures with good safety, supporting further research into the effectiveness of D-cycloserine for chronic back pain.

Gitelman-like Syndrome with Kanamycin Toxicity.

A 22 year-old lady with multi-drug-resistant pulmonary tuberculosis was on Kanamycin, Cycloserine, Ethionamide, Pyrazinamide and Moxifloxacin since more than two months. She presented with muscle cramps and carpopedal spasm. Investigation revealed hypokalemia and metabolic alkalosis. She also had hypomagnesemia, hypochloremia and hypocalciuria. Serum urea and creatinine levels were normal. Patient was treated with intravenous and oral potassium chloride. Kanamycin was stopped. Metabolic alkalosis and hypokalemia improved gradually over one month. Biochemical parameters were like Gitelman's syndrome but it reversed with stoppage of Kanamycin. Gitelman-like syndrome with Kanamycin toxicity has not been reported in literature previously.

Frequency of adverse events observed with second-line drugs among patients treated for multidrug-resistant tuberculosis.

BACKGROUND: Multidrug-resistant tuberculosis (MDR-TB) is considered to be a worldwide problem with notoriously difficult and challenging treatment. Adverse events associated with second-line drugs (SLDs) can have severe impact on efficient management. OBJECTIVE: To know the frequency of adverse events due to SLDs in patients of MDR-TB. DESIGN: A prospective cohort analysis of 98 MDR-TB patients enrolled between June 2009 to February 2010 was conducted in Department of Pulmonary Medicine, King George Medical University, Lucknow, India. All the patients were provided standardized regimen. Adverse events associated with treatment were recognized primarily by clinical evidence and/or laboratory investigations that were advised at baseline and whenever clinically indicated during course of treatment. Adverse events were considered major if required permanent discontinuation or substitution of drugs. RESULTS: 119 adverse events were reported in 46 (46.9%) patients. The grouped adverse events were most commonly gastrointestinal that was observed with a frequency of 48 (40.3%) followed by ototoxicity in 28 (23.6%), and neurological in 21 (17.6%). 17 (17.4%) patients had major adverse events requiring permanent discontinuation or substitution of drugs that included deafness and tinnitus in 5 (5.1%) followed by psychosis in 4 (4.1%). None of the patients stopped complete regimen due to adverse events. The treatment success rate was observed to be 71 (72.4%). CONCLUSIONS: MDR-TB can be cured successfully with appropriate combination of drugs if adverse events associated with them can be managed aggressively and timely. Newer and less toxic drugs are urgently needed to treat MDR-TB patients.

A randomized, placebo-controlled trial of D-cycloserine for the enhancement of social skills training in autism spectrum disorders.

BACKGROUND: Researchers have demonstrated that d-cycloserine (DCS) can enhance the effects of behavioral interventions in adults with anxiety and enhances prosocial behavior in animal models of autism spectrum disorders (ASD). This study extended upon this background by combining DCS with behavioral social skills therapy in youth with ASD to assess its impact on the core social deficits of ASD. We hypothesized that DCS used in combination with social skills training would enhance the acquisition of social skills in children with ASD. METHODS: A 10-week, double-blind, placebo-controlled trial of DCS (50 mg) given 30 min prior to weekly group social skills training was conducted at two sites. Children with ASD were randomized to receive 10 weeks (10 doses) of DCS or placebo in a 1:1 ratio. RESULTS: No statistically significant difference attributable to drug treatment was observed in the change scores for the primary outcome measure, the Social Responsiveness Scale (SRS), total score (p = 0.45), or on secondary outcome measures. CONCLUSIONS: The results of this trial demonstrated no drug-related short-term improvement on the primary outcome measure, or any of the secondary outcome measures. However, an overall significant improvement in SRS total raw score was observed from baseline to end of treatment for the entire group of children with ASD. This suggests a need to further study the efficacy of the social skills training protocol. Limitations to the current study and areas for future research are discussed. TRIAL REGISTRATION: ClinicalTrials.govNCT01086475.

D-Cycloserine in Neuropsychiatric Diseases: A Systematic Review.

D-Cycloserine, known from tuberculosis therapy, has been widely introduced to neuropsychiatric studies, since its central active mechanism as a partial NMDA-agonist has been found. In this review, we evaluate its therapeutic potential in neuropsychological disorders and discuss its pitfalls in terms of dosing and application frequency as well as its safety in low-dose therapy. Therefore, we identified 91 clinical trials by performing a Medline search. We demonstrate in part preliminary but increasing evidence that D-cycloserine may be effective in various psychiatric diseases, including schizophrenia, anxiety disorders, addiction, eating disorders, major depression, and autism as well as in neurological diseases, including dementia, Alzheimer's disease, and spinocerebellar degeneration. D-Cycloserine in low-dose therapy is safe, but there is still a need for new drugs with higher specificity to the different N-methyl-D-aspartate-receptor subunits.

Neuroleptic malignant syndrome in cycloserine-induced psychosis.

A 33-year-old multidrug-resistant tuberculosis female patient diagnosed as cycloserine-induced psychosis developed several neuroleptic side effects such as extrapyramidal reaction, neuroleptic malignant syndrome, and drug-induced parkinsonism while she was being treated with initially haloperidol and then olanzapine over a period of 2 months. Patient's antipsychotic medications were withdrawn, and treatment with bromocriptine showed prompt recovery. The multiple neurological adverse effects which the patient developed had implications on the management of the complications as well as her illness.