Severe and sometimes fatal hepatitis associated with isoniazid therapy may occur and may develop even after many months of treatment. The risk of developing hepatitis is age related. Approximate case rates by age are: 0 per 1,000 for persons under 20 years of age, 3 per 1,000 for persons in the 20–34 year age group, 12 per 1,000 for persons in the 35–49 year age group, 23 per 1,000 for persons in the 50–64 year age group, and 8 per 1,000 for persons over 65 years of age. The risk of hepatitis is increased with daily consumption of alcohol. Precise data to provide a fatality rate for isoniazid-related hepatitis is not available; however, in a U.S. Public Health Service Surveillance Study of 13,838 persons taking isoniazid, there were 8 deaths among 174 cases of hepatitis.
Therefore, patients given isoniazid should be carefully monitored and interviewed at monthly intervals. Serum transaminase concentration becomes elevated in about 10–20 percent of patients, usually during the first few months of therapy, but it can occur at any time. Usually enzyme levels return to normal despite continuance of drug, but in some cases progressive liver dysfunction occurs. Patients should be instructed to report immediately any of the prodromal symptoms of hepatitis, such as fatigue, weakness, malaise, anorexia, nausea, or vomiting. If these symptoms appear or if signs suggestive of hepatic damage are detected, isoniazid should be discontinued promptly, since continued use of the drug in these cases has been reported to cause a more severe form of liver damage.
Patients with tuberculosis should be given appropriate treatment with alternative drugs. If isoniazid must be reinstituted, it should be reinstituted only after symptoms and laboratory abnormalities have cleared. The drug should be restarted in very small and gradually increasing doses and should be withdrawn immediately if there is any indication of recurrent liver involvement. Treatment should be deferred in persons with acute hepatic diseases.
(rifampin and isoniazid capsules USP)
RIFAMATE is a combination capsule containing 300 mg rifampin and 150 mg isoniazid.
For pulmonary tuberculosis in which organisms are susceptible, and when the patient has been titrated on the individual components and it has therefore been established that this fixed dosage is therapeutically effective.
This fixed-dosage combination drug is not recommended for initial therapy of tuberculosis or for preventive therapy.
In the treatment of tuberculosis, small numbers of resistant cells, present within large populations of susceptible cells, can rapidly become the predominating type. Since rapid emergence of resistance can occur, culture and susceptibility tests should be performed in the event of persistent positive cultures.
This drug is not indicated for the treatment of meningococcal infections or asymptomatic carriers of
to eliminate meningococci from the nasopharynx.
Media Articles Related to Rifamate (Rifampin / Isoniazid)
Source: MedicineNet Neutropenia Specialty [2014.01.24]
Title: Tuberculosis (TB)
Category: Diseases and Conditions
Created: 12/31/1997 12:00:00 AM
Last Editorial Review: 1/24/2014 2:28:22 AM
'Alarming' Rise Seen in Drug-Resistant Tuberculosis
Source: MedicineNet Tuberculosis Skin Test (PPD Skin Test) Specialty [2012.08.31]
Title: 'Alarming' Rise Seen in Drug-Resistant Tuberculosis
Category: Health News
Created: 8/30/2012 2:05:00 PM
Last Editorial Review: 8/31/2012 12:00:00 AM
Published Studies Related to Rifamate (Rifampin / Isoniazid)
Treatment completion and costs of a randomized trial of rifampin for 4 months versus isoniazid for 9 months. [2004.08.15]
There is little published information regarding treatment completion, safety, and efficacy of rifampin administered daily for 4 months-a recommended alternative to 9 months of isoniazid for therapy of latent tuberculosis infection. In an open-label randomized trial at a university-affiliated respiratory hospital, consenting patients whose treating physician had recommended therapy for latent tuberculosis infection were randomized to daily self-administered rifampin for 4 months or daily self-administered isoniazid for 9 months...
Initial experience on rifampin and pyrazinamide vs isoniazid in the treatment of latent tuberculosis infection among patients with silicosis in Hong Kong. [2003.12]
CONCLUSION: A higher incidence of hepatotoxicity was associated with rifampin plus pyrazinamide than isoniazid in the treatment of latent tuberculosis infection among patients with silicosis in Hong Kong.
Rifampin and pyrazinamide vs isoniazid for prevention of tuberculosis in HIV-infected persons: an international randomized trial. Terry Beirn Community Programs for Clinical Research on AIDS, the Adult AIDS Clinical Trials Group, the Pan American Health Organization, and the Centers for Disease Control and Prevention Study Group. [2000.03.15]
CONTEXT: Because of problems with adherence, toxicity, and increasing resistance associated with 6- to 12-month isoniazid regimens, an alternative short-course tuberculosis preventive regimen is needed. OBJECTIVE: To compare a 2-month regimen of daily rifampin and pyrazinamide with a 12-month regimen of daily isoniazid in preventing tuberculosis in persons with human immunodeficiency virus (HIV) infection... CONCLUSIONS: Our data suggest that for preventing tuberculosis in HIV-infected patients, a daily 2-month regimen of rifampin and pyrazinamide is similar in safety and efficacy to a daily 12-month regimen of isoniazid. This shorter regimen offers practical advantages to both patients and tuberculosis control programs.
Risk factors for rifampin-monoresistant tuberculosis: A case-control study. [1999.02]
Rifampin is the cornerstone of short-course chemotherapy for the treatment of tuberculosis (TB). Rifampin monoresistance (RMR) is less common than resistance to isoniazid alone or in combination with other antituberculous medications... Cases were frequently noncompliant with previous treatment for TB, had a history of incarceration, and had poor outcomes.
Pharmacokinetics of rifampin under fasting conditions, with food, and with antacids. [1999.01]
STUDY OBJECTIVES: Determine the intrasubject and intersubject variability in, and the effects of food or antacids on, the pharmacokinetics of rifampin (RIF)... CONCLUSIONS: These changes in Cmax, Tmax, and AUC0-infinity can be avoided by giving RIF on an empty stomach whenever possible.
Clinical Trials Related to Rifamate (Rifampin / Isoniazid)
Short-Course Isoniazid and Rifampin Compared With Isoniazid for Latent Tuberculosis Infection [Terminated]
The objective of the study was to compare the compliance and the side effects of a short
course to treatment of latent tuberculosis infection during 3 months(isoniazid plus
rifampin)group I, with the standard course for 6 months(isoniazid)group II .Prospective,
comparative, randomized and open trial of patients with positive TST and the suitable
criteria for treatment, in accordance with the guidelines of the CDC, excluding HIV
infection. 105 patients were included. In Conclusion, a short course with isoniazid plus
rifampin during 3 months shown better compliance with a lower percentage of abandonment that
the course 6H. Tolerance is similar in the two courses.
Isoniazid Dose Adjustment According to NAT2 Genotype (IDANAT2) [Recruiting]
The study is conducted to compare safety and efficacy of isoniazid administered as an
adjusted dose based on NAT2 (arylamine N-acetyltransferase type 2)genotype and as a standard
The hypothesis is that the genotype-adjusted dose is superior to the standard dose with
regard to hepatotoxicity and early treatment failure, respectively, in the group of slow and
rapid acetylators of NAT2.
TBTC Study 24: Intermittent Treatment of TB With Isoniazid Resistance or Intolerance [Active, not recruiting]
This study is a prospective, open-label, nonrandomized trial using a largely-intermittent,
six-month tuberculosis treatment regimen among patients who will not receive isoniazid due to
the presence of initial isoniazid resistance or intolerance. Subjects are enrolled after
resistance or intolerance to isoniazid has been documented, and are treated for a total of
six months (nine months if baseline chest x-ray shows cavitation and 2-month sputum culture
is positive) with twice weekly or thrice weekly rifampin, ethambutol, and pyrazinamide.
A Trial of Isoniazid for the Reversion of Interferon Gamma ELISPOT in Tuberculosis (TB) Case Contacts [Recruiting]
There are new TB vaccines already developed that need to be tried in humans to assess their
The researchers had previously shown that production of interferon gamma by T cells in
response to TB antigens is a more specific marker of TB infection.
The researchers hypothesize that this can be used as a reliable early marker of TB vaccine
efficacy. The researchers expect to show a significantly increased reversion of this test in
household contacts of TB patients given Isoniazid prophylaxis treatment for 6 months.
TBTC Study 23A: Pharmacokinetics of Intermittent Isoniazid and Rifabutin in HIV-TB [Completed]
1) To determine the proportion of patients with HIV-related tuberculosis who have abnormal
pharmacokinetic parameters for isoniazid and rifabutin.
1. To determine risk factors for abnormal pharmacokinetic parameters for isoniazid and
2. To evaluate the correlation between pharmacokinetic parameters of isoniazid and
rifabutin and the occurrence of toxicity attributed to antituberculous therapy.
3. To evaluate the correlation between pharmacokinetic parameters of isoniazid and
rifabutin and the efficacy of TB therapy.
4. To define and correlate phenotypic INH acetylator status with the results of genotypic
acetylator data obtained in the parent trial.
Page last updated: 2014-01-24