Isoniazid-induced bullous skin reaction

Response to Modified Antitubercular Drug Regime and Antiretroviral Therapy in a Case of HIV Infection with Disseminated Tuberculosis with Isoniazid Induced Toxic Epidermal Necrolysis

Toxic epidermal necrolysis (TEN) is a potentially life-threatening disorder characterized by widespread erythema, necrosis, and bullous detachment of the epidermis and mucous membranes. Without proper management,TEN can cause sepsis leading to death of the patient. Though TEN is commonly drug induced, Isoniazid (INH) has been uncommonly associated with TEN. As INH is one of the first line drugs in treatment of tuberculosis, TEN induced INH needs modification of antitubercular therapy (ATT) with withdrawal of INH from the treatment regime along with other supportive treatments. Patients with HIV infection and disseminated tuberculosis need to be urgently initiated on an effective ATT on diagnosis of tuberculosis. However, if the patient develops potential life-threatening toxicity to first line antitubercular drugs like INH, an alternative effective ATT combination needs to be started as soon as the condition of the patient stabilizes as most of these patients present in advanced stage of HIV infection and this is to be followed by antiretroviral therapy (ART) as per guidelines. The present case reports the effectiveness of an ATT regime comprising Rifampicin, Pyrazinamide, Ethambutol, and Levofloxacin along with ART in situations where INH cannot be given in disseminated tuberculosis in HIV patients.

Adverse reactions to first-line antituberculosis drugs

INTRODUCTION

Tuberculosis continues to be a major cause of morbidity and mortality worldwide. Currently available drugs are effective for treatment of the disease or latent infection, but may cause serious adverse effects.

METHODS

The authors reviewed the literature for side effects of five first-line antituberculous medications (isoniazid, rifampin, pyrazinamide, ethambutol and streptomycin). Incidence of the major side effects were compiled with particular attention to the incidence of isoniazid hepatotoxicity.

RESULTS

Hepatotoxicity to isoniazid is a serious problem. Although overall incidence may be decreasing, incidence averaged 9.2 per 1000 patients who were compliant, in multiple studies, with a case fatality rate of 4.7%. The incidence is higher with increasing age. Other serious adverse effects include dermatological, gastrointestinal, hypersensitivity, neurological, haematological and renal reactions. They can lead to drug discontinuation (in up to 10% of patients) or even more serious morbidity or mortality.

CONCLUSIONS

Side effects to antituberculosis drugs are common, and include hepatitis, cutaneous reactions, gastrointestinal intolerance, haematological reactions and renal failure. These adverse effects must be recognised early, to reduce associated morbidity and mortality.