Neurological manifestations and toxicities of the antituberculosis drugs. A review

Characteristics of isoniazid-induced psychosis: a systematic review of case reports and case series

PURPOSE

Isoniazid, a first-line antitubercular drug, is associated with nervous system adverse drug reactions such as seizures, peripheral neuropathy, and psychosis. This systematic review of case reports and case series aimed to characterize the demographic, social, and clinical factors associated with isoniazid-induced psychosis in patients with active tuberculosis (TB) and those who received isoniazid for latent TB infection (LTBI).

METHODS

We comprehensively searched the Embase, PubMed, and Scopus databases to identify relevant studies published between the date of inception of the database and June 2024.

RESULTS

A total of 28 studies, including 21 case reports and 7 case series involved 37 patients who developed isoniazid-induced psychosis. A higher frequency of isoniazid-induced psychosis was observed during the first 2 months of treatment, with a relatively early onset observed among patients aged 18 years or less. Delusions and/or hallucinations are the common symptoms of isoniazid-induced psychosis. Psychomotor disturbances, disorganized speech or formal thought disorder, disorganized or abnormal behaviour, and neuropsychiatric symptoms (sleep disturbances, hostility or aggression, confusion, affective symptoms, anxiety symptoms, and cognitive difficulties) were the other symptoms observed in the included studies. More than 80% of cases rechallenged with isoniazid resulted in the recurrence of psychotic symptoms.

CONCLUSION

Patients with TB and LTBI should be assessed for psychotic and neuropsychiatric symptoms during isoniazid therapy, mainly in the first 2 months. Further research is required to understand the impact of underlying risk factors, such as genetic predisposition and isoniazid pharmacokinetics, as well as the clinical utility and dosage recommendations of pyridoxine for managing isoniazid-induced psychosis.

Effect of Multicomponent Exercise Program on Pain and Functional Mobility in Antitubercular Drug Therapy-Induced Peripheral Neuropathy in Pulmonary Tuberculosis Survivors

OBJECTIVES

 Exercise therapy is a pivotal component in the multidisciplinary approach to managing tuberculosis (TB)-related peripheral neuropathy (PN). A personalized exercise protocol maximizes therapeutic benefits while minimizing the risk of symptom exacerbation. This study aimed to determine the effect of multicomponent exercise programs on pain and functional mobility in antitubercular drug therapy-induced PN in pulmonary TB survivors.

METHODS

In the approved experimental study, 110 participants with antitubercular study drug-induced PN were randomly assigned to two groups, and data were analyzed using IBM SPSS Statistics for Windows, Version 26 (Released 2019; IBM Corp., Armonk, New York, United States). The study's purpose was to evaluate the efficacy of a multicomponent exercise program on PN symptoms.

RESULTS

The study assessed a multicomponent exercise regimen's effectiveness in individuals with TB-related PN. The experiment group demonstrated noteworthy pain reduction (p < 0.0001), improvement in neurological symptoms (p < 0.0001), and better functional outcomes in the 12-minute walk test (p < 0.0001) and sit-and-reach test (p < 0.0001). Conversely, the control group exhibited less significant improvements. The low p-values indicate the intervention's effectiveness, emphasizing its impact on pain reduction, neurological symptoms, and functional abilities in comparing the experimental and control groups.

CONCLUSION

The study demonstrated the significant effectiveness of an eight-week multicomponent exercise program in individuals with pulmonary TB-related PN, showcasing notable improvements in pain reduction and functional mobility compared to a conventional single-component regimen in the control group.

Computational and experimental analyses of alanine racemase suggest new avenues for developing allosteric small-molecule antibiotics

Given the ever-present threat of antibacterial resistance, there is an urgent need to identify new antibacterial drugs and targets. One such target is alanine racemase (Alr), an enzyme required for bacterial cell-wall biosynthesis. Alr is an attractive drug target because it is essential for bacterial survival but is absent in humans. Existing drugs targeting Alr lack specificity and have severe side effects. We here investigate alternative mechanisms of Alr inhibition. Alr functions exclusively as an obligate homodimer, so we probed seven conserved interactions on the dimer interface, distant from the enzymatic active site, to identify possible allosteric influences on activity. Using the Alr from Mycobacterium tuberculosis (MT) as a model, we found that the Lys261/Asp135 salt bridge is critical for catalytic activity. The Lys261Ala mutation completely inactivated the enzyme, and the Asp135Ala mutation reduced catalytic activity eight-fold. Further investigation suggested a potential drug-binding site near the Lys261/Asp135 salt bridge that may be useful for allosteric drug discovery.

MDR Tuberculosis Treatment

Multidrug-resistant (MDR) tuberculosis (TB), resistant to isoniazid and rifampicin, continues to be one of the most important threats to controlling the TB epidemic. Over the last few years, there have been promising pharmacological advances in the paradigm of MDR TB treatment: new and repurposed drugs have shown excellent bactericidal and sterilizing activity against Mycobacterium tuberculosis and several all-oral short regimens to treat MDR TB have shown promising results. The purpose of this comprehensive review is to summarize the most important drugs currently used to treat MDR TB, the recommended regimens to treat MDR TB, and we also summarize new insights into the treatment of patients with MDR TB.

Further Insights into the Oxidative Pathway of Thiocarbonyl-Type Antitubercular Prodrugs: Ethionamide, Thioacetazone, and Isoxyl

A chemical activation study of the thiocarbonyl-type antitubercular prodrugs, ethionamide (ETH), thioacetazone (TAZ), and isoxyl (ISO), was performed. Biomimetic oxidation of ethionamide using H₂O₂ (1 equiv) led to ETH-SO as the only stable S-oxide compound, which was found to occur in solution in the preferential form of a sulfine (ETH═S═O vs the sulfenic acid tautomer ETH-S-OH), as previously observed in the crystal state. It was also demonstrated that ETH-SO is capable of reacting with amines, as the putative sulfinic derivative (ETH-SO₂H) was supposed to do. Unlike ETH, oxidation of TAZ did not allow observation of the mono-oxygenated species (TAZ-SO), leading directly to the more stable sulfinic acid derivative (TAZ-SO₂H), which can then lose a SO_xH group after further oxidation or when placed in a basic medium. It was also noticed that the unstable TAZ-SO intermediate can lead to the carbodiimide derivative as another electrophilic species. It is suggested that TAZ-SOH, TAZ-SO₂H, and the carbodiimide compound can also react with NH₂-containing nucleophilic species, and therefore be involved in toxic effects. Finally, ISO showed a very complex reactivity, here assigned to the coexistence of two mono-oxygenated structures, the sulfine and sulfenic acid tautomers. The mono- and dioxygenated derivatives of ISO are also highly unstable, leading to a panel of multiple metabolites, which are still reactive and likely contribute to the toxicity of this prodrug.

Neurological and Psychiatric Adverse Effects of Antimicrobials

Antimicrobials are a widely used class of medications, but several of them are associated with neurological and psychiatric side effects. The exact incidence of neurotoxicity with anti-infectives is unknown, although it is estimated to be < 1%. Neurotoxicity occurs with all classes of antimicrobials, such as antibiotics, antimycobacterials, antivirals, antifungals and antiretrovirals, with side effects ranging from headaches, anxiety and depression to confusion, delirium, psychosis, mania and seizures, among others. It is important to consider these possible side effects to prevent misdiagnosis or delayed treatment as drug withdrawal can be associated with reversibility in most cases. This article highlights the different neurotoxic effects of a range of antimicrobials, discusses proposed mechanisms of onset and offers general management recommendations. The effects of antibiotics on the gut microbiome and how they may ultimately affect cognition is also briefly examined.

More Than Malnutrition: A Review of the Relationship Between Food Insecurity and Tuberculosis

Despite a significant reduction in tuberculosis (TB) mortality over the past decade, TB remains a leading cause of death worldwide. Food insecurity-through pathways such as malnutrition, mental health impact, and high-risk health behaviors-affects the risk of TB disease, treatment failure, and mortality. We searched the literature for studies reporting on the links between food insecurity and TB. In contrast to the well-documented interactions between food insecurity and HIV/AIDS, we found that the association between food insecurity and TB remains largely understudied-this is especially true with regard to non-nutritional correlations. Mental health and behavioral linkages between TB and food insecurity deserve further attention. An improved understanding of the pathways through which food insecurity impacts TB is crucial to inform evidence-based integration of interventions such as psychological counseling, psychiatric care, harm reduction programs, and efforts to address social determinants of disease within current TB programs.

Seizures following Intoxication with a Common Antituberculosis Drug

Isoniazid is an antimycobacterial agent commonly prescribed in most tuberculosis chemotherapy regimens. Its side effects are widely known including mainly liver toxicity and peripheral neuropathy. The toxic effects of isoniazid are dose-related. Toxic doses are estimated at 35–40 mg/kg and fatal doses at 150 mg/kg. Treatment consists primarily of basic life support, antiepileptic drugs, and pyridoxine. The case is of one of the children with intentional isoniazid poisoning, the drug belonging to an uncle currently under antituberculosis treatment, resulting in tonic-clonic seizures. During her hospitalization in the paediatric intensive care unit, her neurological status as well as her lab values was closely monitored, and despite initial deterioration, the patient was discharged from critical care a week after full recovery.

Complications associated with antibiotic administration: neurological adverse events and interference with antiepileptic drugs

Antibiotic use is associated with toxic effects involving the peripheral and central nervous systems and it may interfere with antiepileptic drugs, causing significant variations in their serum levels and activity. Prompt identification of neurological complications during antibiotic therapy is important in order to make appropriate modifications to medication. Characteristics of the drug and the patient, including age and underlying diseases, may favour these complications. The main aim of this study was to review the neurological adverse events that may follow antibiotic administration, the mechanisms that cause them, and the possibility of prevention and treatment. Moreover, the interference of antibiotics with serum levels and the activity of antiepileptic drugs are discussed. The results demonstrate that antibiotic-associated adverse events involving the nervous system are relatively uncommon and are only rarely severe and irreversible, although neurotoxicity has been reported for several antibiotics. Moreover, for patients receiving antiepileptic drugs, monitoring of drug serum levels to avoid the risk of toxicity or inadequate therapy is mandatory during antibiotic treatment. Areas for future research include the effects of combined antibiotic therapies as well as multiple antiepileptic drugs in study populations with an adequate sample size, including neonates and infants, patients with pharmacoresistant epilepsy and elderly patients.

A Case of Seizure and Metabolic Acidosis Due to Renal Adjustment Dosage of Isoniazid in an Elderly Woman

Isoniazid is one of the most commonly used antituberculosis drug. Acute into xication is characterized by repetitious convulsions, high anion gap metabolic a cidosis and coma. The basis of theraphy consists of parental pyridoxine admi nistration in a dose equivalent to that of isoniazid ingested. Here we present a case of seizure and metabolic acidosis due to only renal adjustment dosage of Isoniazid in an elderly woman.

Psychiatric morbidity and other factors affecting treatment adherence in pulmonary tuberculosis patients

As the overall prevalence of TB remains high among certain population groups, there is growing awareness of psychiatric comorbidity, especially depression and its role in the outcome of the disease. The paper attempts a holistic approach to the effects of psychiatric comorbidity to the natural history of tuberculosis. In order to investigate factors associated with medication nonadherence among patients suffering from tuberculosis, with emphasis on psychopathology as a major barrier to treatment adherence, we performed a systematic review of the literature on epidemiological data and past medical reviews from an historical perspective, followed by theoretical considerations upon the relationship between psychiatric disorders and tuberculosis. Studies reporting high prevalence rates of psychiatric comorbidity, especially depression, as well as specific psychological reactions and disease perceptions and reviews indicating psychiatric complications as adverse effects of anti-TB medication were included. In sum, data concerning factors affecting medication nonadherence among TB patients suggested that better management of comorbid conditions, especially depression, could improve the adherence rates, serving as a framework for the effective control of tuberculosis, but further studies are necessary to identify the optimal way to address such issues among these patients.

Tuberculosis drugs: new candidates and how to find more

The recent years have witnessed significant progress in the development of new drug candidates for the treatment of TB. While many of these are now in clinical trials, continued research is needed in order to sustain the drug discovery pipeline and meet the increasing needs of TB patients. These include shortening treatment, killing drug-resistant strains, and finding medications compatible with antiretroviral and diabetes therapy. Nowadays, TB drug discovery benefits from high-throughput screening methods, availability of conditional expression systems, and biophysical and biochemical techniques that enable target-based rational drug design. This article reviews the current state of TB drug development and discusses possible approaches to finding new leads.

Nervous system effects of antituberculosis therapy

Nervous system toxicity with current antituberculosis pharmacotherapy is relatively uncommon, although the frequency of the usage of antituberculosis therapy requires that physicians be aware of such toxicity. Antituberculosis therapy manifests both central and peripheral nervous system effects, which may compromise patient compliance. Among the traditional forms of first-line antituberculosis therapy, isoniazid is most often associated with nervous system effects, most prominently peripheral neuropathy, psychosis and seizures. Adverse events are reported with other antituberculosis therapies, the most prominent being optic neuropathy with ethambutol and ototoxicity and neuromuscular blockade with aminoglycosides. The second-line agent with the most adverse effects is cycloserine, with psychosis and seizures, the psychosis in particular limiting its usage. Fluoroquinolones are rare causes of seizures and delirium. Newer forms of therapy are under development, but to date no significant neurotoxicity is documented with these agents. Future needs include the development of surveillance mechanisms to increase recognition of nervous system toxicities. It is also hoped that the development of new pharmacogenomic assays will help with the identification of patients at risk for these toxicities.

Synthetic EthR inhibitors boost antituberculous activity of ethionamide

The side effects associated with tuberculosis therapy bring with them the risk of noncompliance and subsequent drug resistance. Increasing the therapeutic index of antituberculosis drugs should thus improve treatment effectiveness. Several antituberculosis compounds require in situ metabolic activation to become inhibitory. Various thiocarbamide-containing drugs, including ethionamide, are activated by the mycobacterial monooxygenase EthA, the production of which is controlled by the transcriptional repressor EthR. Here we identify drug-like inhibitors of EthR that boost the bioactivation of ethionamide. Compounds designed and screened for their capacity to inhibit EthR-DNA interaction were co-crystallized with EthR. We exploited the three-dimensional structures of the complexes for the synthesis of improved analogs that boosted the ethionamide potency in culture more than tenfold. In Mycobacterium tuberculosis-infected mice, one of these analogs, BDM31343, enabled a substantially reduced dose of ethionamide to lessen the mycobacterial load as efficiently as the conventional higher-dose treatment. This provides proof of concept that inhibiting EthR improves the therapeutic index of thiocarbamide derivatives, which should prompt reconsideration of their use as first-line drugs.

Oxidative activation of thiacetazone by the Mycobacterium tuberculosis flavin monooxygenase EtaA and human FMO1 and FMO3

Thiacetazone (TAZ) and ethionamide (ETA) are, respectively, thiourea- and thioamide-containing second line antitubercular prodrugs for which there is an extensive clinical history of cross-resistance in Mycobacterium tuberculosis. EtaA, a recently identified flavin-containing monooxygenase (FMO), is responsible for the oxidative activation of ETA in M. tuberculosis. We report here that EtaA also oxidizes TAZ and identify a sulfinic acid and a carbodiimide as the isolable metabolites. Both of these metabolites are derived from an initial sulfenic acid intermediate. Oxidation of TAZ by EtaA at basic pH favors formation of the carbodiimide, whereas neutral or acidic conditions favor formation of the sulfinic acid. The same metabolites are formed from TAZ by human FMO1 and FMO3. The sulfenic acid and carbodiimide metabolites, but not the sulfinic acid product, readily react with glutathione, the first to regenerate the parent drug and the second to give a glutathione adduct. These reactions may contribute to the antitubercular activity and/or toxicity of TAZ.

Traitement des tuberculoses cérébro-méningées

INTRODUCTION

Tuberculous meningitis and brain tuberculomas are currently rare in the western world but remain serious. Improved outcome requires early recognition and treatment of these conditions.

STATE OF ART

Treatment is usually begun before diagnostic confirmation. Therapeutic principles are now better defined thanks to recent recommendations and studies. Antituberculous therapy begins with two months of a combination of four drugs: isoniazid, rifampicin, ethambutol and pyrazinamid. Then follows a longer phase of bitherapy with isoniazid and rifampicin, lasting at least four months but usually extended to seven or ten months as a precaution. Patients at risk of toxic neuropathy should receive pyridoxine supplementation. Corticosteroids must be systematically added during the first eight weeks of treatment, beginning with high dose before progressive tapering. Hyponatremia is common, often induced by emesis and cerebral salt wasting syndrome. Therefore saline supply rather than water restriction is required. Non-obstructive hydrocephaly can usually be managed with diuretic therapy including acetazolamid, sometimes complemented by serial lumbar punctures. Neurosurgical interventions are rarely needed. Monitoring of treatment tolerance and efficacy is mainly clinical. Central nervous system imaging and cerebro-spinal fluid analysis are only required to explain clinical deterioration.

CONCLUSION

With adequate and prompt anti-tuberculous, anti-inflammatory and supportive treatment, the prognosis of central nervous system tuberculosis can be greatly improved.

Holmes' tremor following midbrain Toxoplasma abscess: clinical features and treatment of a case

The label Holmes' tremor defines a rare symptomatic movement disorder frequently occurring with midbrain damage. It appears at rest and worsens adopting a posture and on attempting movements. We describe the case of a patient with Holmes' tremor due to a presumed Toxoplasma abscess of the midbrain. The positive response to a combined therapy with levodopa and isoniazid is also reported.

Evaluation of the teratogenic potential of pyrazinamide in Wistar rats

We have tested Pyrazinamide (PZA), an essential component of modern short-course tuberculosis treatment regimen, for teratogenicity using Wistar rats. The drug was given by oral intubation from 6-15 days of gestation, at doses of 0, 25, 100 and 500 mg/kg body weight per day. Reduction in body weight and food consumption were observed in the treated dams. On day 20 of gestation, all the dams were killed by cervical dislocation and signs of maternal toxicity, reproductive indices and fetal measurements were recorded. Dams given doses of 100 and 500 mg/kg had significantly higher incidence of reabsorbed fetuses, reduced litter size, and impaired neonatal growth than those given no PZA or only 25 mg/kg dose. External visceral and skeletal examination of all fetuses of PZA-treated dams showed several types of variations which were neither dose related nor having a consistent pattern. However, these variations occurred mostly in the dams treated with the dose of 500 mg/kg. In conclusion, these data show that in Wistar rats, only high doses of PZA (100 and 500 mg/kg) produced fetotoxicity. No evidence of teratogenic effect of the drug was observed.

Ocular tuberculosis

In recent years tuberculosis has reemerged as a serious public health problem, raising the possibility that tuberculous eye disease may also become more prevalent. The predominant route by which tubercle bacilli reach the eye is through the bloodstream, after infecting the lungs. The pulmonary loci might not be evident clinically or radiographically. The most common manifestation of ocular tuberculosis in patients with pulmonary tuberculosis is choroiditis. Retinal periphlebitis is rarely caused by direct invasion of the retina by tubercle bacilli. Retinal tuberculosis is usually, but not always, secondary to an underlying choroiditis. Tuberculoprotein hypersensitivity may have a role in the pathogenesis of phlyctenulosis and Eales' disease. Both ocular and orbital tuberculosis are usually unilateral. Skin testing should be performed in selected patients based on the clinical presentation and/or a history of exposure to tuberculosis. The specificity of the PPD skin test for Mycobacterium tuberculosis increases with larger skin reactions and with a history of exposure to an active case of tuberculosis. Because of the potential for serious drug toxicities, empiric treatment with antituberculous chemotherapy should be reserved only for those cases that have an identifiable risk of tuberculous disease.

Isoniazid induced encephalopathy in dialysis patients

Three dialysis patients with extrapulmonary tuberculosis developed confusion 4-14 days after commencement of treatment with anti-tuberculosis drugs, despite the use of prophylactic pyridoxine. Full recovery of conscious state resulted within 1 week in all patients after stopping isoniazid. In 2 patients confusion recurred on rechallenge of the drug. The risk factors of isoniazid induced encephalopathy and the dosage of isoniazid in uraemic patients were discussed.

Isoniazid-associated psychosis: case report and review of the literature

OBJECTIVE

To describe a case of isoniazid-associated psychosis and review the incidence of this adverse effect.

DATA SOURCES

Information about the patient was obtained from the medical chart. A MEDLINE search of the English-language literature published from 1950 to 1992 was conducted and Index Medicus was manually searched for current information.

STUDY SELECTION

All case reports describing isoniazid-associated psychosis were reviewed.

DATA EXTRACTION

Studies were evaluated for the use of isoniazid, symptoms of psychosis, onset of symptoms, and dosage of isoniazid.

DATA SYNTHESIS

The case report is compared with others reported in the literature. The incidence of isoniazid-associated psychosis is rare.

CONCLUSIONS

The mechanism of isoniazid-associated psychosis is uncertain. It appears that isoniazid was associated with the psychosis evident in our patient and in the cases reviewed.

Clinical features, pathogenesis and management of drug-induced seizures

Many classes of pharmacological agents have been implicated in cases of drug-induced seizures. The list includes antidepressant drugs, lithium salts, neuroleptics, antihistamines (H1-receptor antagonists), anticonvulsants, central nervous system stimulants, general and local anaesthetics, antiarrhythmic drugs, narcotic and non-narcotic analgesics, non-steroidal anti-inflammatory drugs, antimicrobial agents, antifungal agents, antimalarial drugs, antineoplastic drugs, immunosuppressive drugs, radiological contrast agents and vaccines. For each of these classes of drugs, this article offers a revision of the literature and emphasises in particular the frequency of the adverse reaction, its clinical presentation, its presumed epileptogenic mechanism and the therapeutic strategy for the management of drug-induced seizures. An attempt is also made to distinguish seizures induced by standard dosages from those provoked by accidental or self-induced intoxication. For some classes of drugs such as antidepressants, neuroleptics, central nervous system stimulants (e.g. theophylline, cocaine, amphetamines) and beta-lactam antibiotics, seizures are a well recognised adverse reaction, and a large body of literature has been published discussing exhaustively the major aspects of the issue; sufficient data are available also for the other classes of pharmacological agents mentioned above. In contrast, several other drugs [e.g. allopurinol, digoxin, cimetidine, protirelin (thyrotrophin releasing hormone), bromocriptine, domperidone, insulin, fenformin, penicillamine, probenecid, verapamil, methyldopa] have not been studied thoroughly under this aspect, and the only source of information is the occasional case report. This review does not address the issue of seizures induced by drug withdrawal.

A review of the Redman syndrome and rifampicin overdosage

The literature was reviewed for cases of cutaneous pigmentation induced by rifampicin overdosage. 29 examples have been described, in which 2 general groups of individuals were observed. The first consisted of older individuals (average age 27.1 years) who attempted suicide. A prior history of suicide attempts, depression and substance abuse was a predominant factor in these patients. The second group included generally younger patients (average age 2.9 years) in whom misformulation of rifampicin preparations for treatment of Haemophilus influenzae Type B resulted in bright reddish-orange discoloration to the skin. The time to clinical appearance of skin discoloration was approximately 2.2 hours after administration. Periorbital or facial oedema occurred in 72.4% of the patients, pruritus in 62.1% and either nausea, vomiting or diffuse abdominal tenderness in 51.7%. Limited laboratory data are available but these indicate that all patients had elevated levels of total bilirubin. Histological examination in selected individuals revealed rifampicin crystal deposits in the nasopharynx, gastrointestinal tract and lining of the aorta. In adults, it appears that a dose of at least 14 g of rifampicin is necessary before cardiovascular-pulmonary arrest occurs. Other than general supportive measures, very few methods are described in the literature for the treatment of acute intoxications with this drug. A differential diagnosis of other causes of reddish-orange pigmentation is discussed, together with clinical information to differentiate these cases from toxic rifampicin ingestion.

Teratology of the antituberculosis drugs

The teratogenic effects of twelve antituberculosis drugs in animal models and man are reviewed. A number of congenital malformations have been associated with the use of these agents; however, for the most part, the birth defect rate is not above that expected for the normal population. Isoniazid and ethambutol are considered the safest for maternal use. Although rifampicin appears to be more problematic, if the disease is severe or extensive, it may be added, preferably after the first trimester. Streptomycin and kanamycin are associated with eighth cranial nerve damage and should be avoided if possible during cyesis. At least five of these compounds have documented evidence of transplacental passage. In consideration of the number of drugs that are available for treatment, routine therapeutic abortions in pregnant females with tuberculosis is not medically indicated.

Contact dermatitis to antituberculosis drugs

The literature has been reviewed for contact dermatitis occurring to antituberculosis agents. Of the 12 known drugs, 6 (isoniazid, rifampicin, ethambutol, para-aminosalicylic acid, streptomycin and kanamycin) have been documented by patch test to cause this type of dermatitis in certain individuals. Cross sensitization has been observed to contribute significantly to the allergic reactions noted from isoniazid, streptomycin, and kanamycin. Hyposensitization has also been discussed in this review.