Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “ETHAMBUTOL”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,189 records · Page 66Linked to original sources
PubMed1986

American Thoracic Society. Medical Section of the American Lung Association: Treatment of tuberculosis and tuberculosis infection in adults and children.

Treatment of tuberculosis: A 6-month regimen consisting of isoniazid, rifampin, and pyrazinamide given for 2 months followed by isoniazid and rifampin for 4 months is effective treatment in patients with fully susceptible organisms who comply with the treatment regimen. It may be advisable to include ethambutol in the initial phase when isoniazid resistance is suspected. A 9-month regimen consisting of isoniazid and rifampin is also highly successful. The need for an additional drug in the initial phase is not certain unless isoniazid resistance is suspected, in which case ethambutol should be included until susceptibility tests have been reported. In the presence of documented resistance to isoniazid, rifampin and ethambutol, perhaps supplemented initially by pyrazinamide, should be given for minimum of 12 months. Children should be treated in essentially the same ways as adults using appropriately adjusted doses of the drugs. However, consideration must be given to the important differences in the approach to management in children. Extrapulmonary tuberculosis should be managed according to the principles and with the drug regimens outlined to pulmonary tuberculosis. The major determinant of the outcome of treatment is patient compliance. Careful attention should be paid to measures designed to foster compliance and to ensure that patients take the drugs as prescribed. Treatment of tuberculous infection: Preventive therapy with isoniazid given for 6 to 12 months is effective in decreasing the risk of future tuberculosis. (ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Pharmacokinetics of antituberculosis drugs in patients.

The pharmacokinetics of rifampin, isoniazid, and ethambutol were determined in 26 ambulatory male patients (aged 49.5 +/- 9.9 yr) with tuberculosis. Rifampin and isoniazid were given individually or together, with or without ethambutol; studies were done after a single dose and after chronic administration. Under the study conditions, with large variability in the extent of disease and physical status and history of alcohol and tobacco abuse and narrow age range, the pharmacokinetics of these three antituberculosis drugs were not modified significantly by patient age. Furthermore, appreciable drug-drug interactions did not occur when the three drugs were administered concurrently. Self-induction of rifampin clearance by chronic dosing with the drug may lead to subtherapeutic levels of rifampin. Administration of isoniazid and ethambutol in two divided doses resulted in peak plasma concentrations below the accepted therapeutic levels of the two drugs. Our findings indicate that at least in the middle-aged patients with tuberculosis, the current single daily dose, multiple-drug regimen is therapeutically sound pharmacokinetically, and clinicians do not have to make adjustments in dosages of these drugs for age and the extent of disease.

Adult↗
PubMed2005

Inactive hepatitis B surface antigen carrier state and hepatotoxicity during antituberculosis chemotherapy.

STUDY OBJECTIVES: To determine whether inactive hepatitis B surface antigen (HBsAg) carriers are at a higher risk of drug-induced hepatotoxicity than control subjects during antituberculosis treatment with standard short-course regimens of isoniazid, rifampin, ethambutol, and/or pyrazinamide. DESIGN: Retrospective case-control study. SETTING: Tertiary university medical center. PATIENTS: One hundred ten inactive HBsAg carriers with newly diagnosed active tuberculosis who had been treated with isoniazid, rifampin, ethambutol, and/or pyrazinamide were included in the study population. Inactive HBsAg carriers were defined as follows: (1) positive for HbsAg; (2) negative for hepatitis B e antigen (HBeAg), positive for antibody to HBeAg; (3) < 10(5) copies per mL of serum hepatitis B virus DNA; and (4) normal pretreatment aspartate aminotransferase (AST)/alanine aminotransferase (ALT) levels. Ninety-seven HBsAg-negative patients who received standard antituberculosis medication were selected as control subjects. RESULTS: The baseline characteristics of the 110 inactive HBsAg carriers were similar to those of the 97 noncarriers. A total of 85% of persons in both groups had received an initial treatment regimen that included pyrazinamide. Thirty-eight inactive HBsAg carriers (35%) and 19 control subjects (20%) exhibited elevated liver enzyme levels during antituberculosis treatment (p = 0.016). Drug-induced hepatotoxicity, which was defined as a liver transaminase level of >/= 120 IU/L, occurred more frequently in HBsAg carriers (9 of 110 carriers; 8%) than in control subjects (4 of 97 control subjects; 4%), although this was not a statistically significant discrepancy (p = 0.230). More importantly, HBsAg carriers (n = 9; 8%) who received antituberculosis therapy evidenced a higher proportion of moderate-to-severe drug-induced hepatotoxicity when compared with the control subjects (n = 2; 2%; p = 0.05). Isoniazid and rifampin were reintroduced as therapy after AST/ALT levels returned to baseline values in 10 patients (6 HBsAg carriers and 4 control subjects) among the 13 patients exhibiting drug-induced hepatotoxicity, and these retrials proved to be successful in 7 patients (5 HBsAg carriers and 2 control subjects). CONCLUSIONS: Tuberculosis treatment in HBsAg-positive and HBeAg-negative inactive carriers could be pursued in the usual manner, using standard short-course regimens of isoniazid, rifampin, ethambutol, and/or pyrazinamide, with the condition that monthly liver function tests are performed.

Adult↗
PubMed2005

Susceptibility pattern and epidemiology of Mycobacterium tuberculosis in a Saudi Arabian hospital: a 15-year study from 1989 to 2003.

OBJECTIVES: The objective of this study was to examine the prevalence and trends of drug resistance of Mycobacterium tuberculosis at the Saudi Aramco Medical Services Organization. METHODS: We retrospectively identified M tuberculosis isolates from January 1989 to December 2003. Antimicrobial susceptibility and clinical data were collected and analyzed. RESULTS: From 1989 to 2003, 276 nonrepetitive culture-positive cases were identified. There were 236 Saudis (84.6%), and the remainder were non-Saudis (15.4%). M tuberculosis isolates were obtained from pulmonary specimens (49%) and extrapulmonary sites (51%). The resistance rates of M tuberculosis to tested first-line agents were as follows: isoniazid, 12.5%; ethambutol, 7.5%; streptomycin; 6.9%; and rifampin, 1.1%. The resistance rate to isoniazid and streptomycin was 1.8%, the rate to isoniazid and rifampin was 0.7%, and the rate to isoniazid and ethambutol was 2.5%. The resistance rate to isoniazid, ethambutol, and streptomycin was 0.7% CONCLUSION: M tuberculosis resistance to isoniazid showed a decreased rate over the study period from 20 to 5.7%. The rate of multidrug-resistant M tuberculosis remained low.

Adolescent↗
PubMed1979

Antimicrobial activity of antituberculosis agents against anaerobic bacteria.

Anaerobic infections may coexist with tuberculosis, and can be mistaken for one another. The effect of therapy with antituberculosis chemotherapeutic agents against anaerobic bacteria (with the exception of rifampin) is unknown. We therefore examined the in vitro efficacy of certain commonly used antituberculosis agents (rifampin, isoniazid, and ethambutol) against 370 strains of anaerobic bacteria, including 86 isolates of Bacteroides fragilis. Rifampin at a concentration of 2 microgram/ml inhibited 91 percent of all anaerobic isolates. Both ethambutol and isoniazid were totally ineffective against any of the anaerobes tested, even at 64 microgram/ml. Therapy with rifampin in an unsuspected anaerobic infection can be misdiagnosed for tuberculosis. Therefore, when tuberculosis is suspected, isoniazid and ethambutol can be used and rifampin withheld until the acid-fast bacilli are demonstrated by additional diagnostic procedures, such as transtracheal aspiration.

Actinomyces↗
PubMed1986

Tuberculosis in Korea. The relationship between prior therapy and drug resistance.

A review of 121 culture-positive cases of pulmonary tuberculosis from 1979 to 1984, including both Korean and American patients, at the major US military hospital in Korea indicated that most antituberculosis drug resistance occurred in patients with a history of previous antituberculosis therapy. The 98 patients without previous therapy who were not household contacts of a known resistant case had low rates of drug resistance (7 percent to isoniazid, 5 percent to streptomycin, 2 percent to p-aminosalicylic acid, and none to rifampin or ethambutol). All were sensitive to at least two of the drugs in the commonly prescribed regimen of isoniazid, rifampin, and ethambutol. In contrast, both patients who were household contacts of a known resistant case and 11 (52 percent) of the 21 patients with previous therapy had drug-resistant organisms. Our data support the use of isoniazid as preventive therapy for those who develop tuberculin reactivity while in Korea, in the absence of close contact with a known resistant case. Our data also suggest that the regimen of isoniazid, rifampin, and ethambutol is appropriate initial therapy for active disease acquired in Korea, provided that an adequate history excluding these risk factors can be obtained.

Aminosalicylic Acid↗
PubMed2001

[Observations of properties of the L-form of M. tuberculosis induced by the antituberculosis drugs].

OBJECTIVES: To investigate the mechanism of generation of L-form of M. tuberculosis and its significance on the development, diagnosis and treatment of tuberculosis. METHODS: M. tuberculosis was inoculated into the non-high osmotic medium with rifampin, isoniazid or ethambutol and then the L-form was observed by microscopy daily. The cultures were filtrated to get the pure cultures of stable L-form by subculture with the non-high osmotic medium and characteristics of morphology, growth, susceptibilities to the antibacterial drugs and the special gene of M. tuberculosis were observed when the pure subcultures of the L-form were isolated. RESULTS: L-form of M. tuberculosis was induced by the concentrations of routine inhibition test of rifampin, isoniazid or ethambutol. The L-form would not be susceptible to the above mentioned antituberculosis drugs but susceptible to streptomycin, erythromycin, ofloxacin, norfloxacin and others. The morphologies of L-form were irregular or spherical with single, paired or chain form, and growth under the bottom of the medium but not movement or adhere to the glass. The L-form was negative by acid-fast stain and negative or positive by Gram stain. The gene of L-form reacted with the PCR kit for the M. tuberculosis and showed the same band. CONCLUSIONS: M. tuberculosis could be killed by rifampin, isoniazid or ethambutol but also could be induced to become the L-form by these antituberculosis drugs, and it is one of the important factor that affecting the effect of treatment of the tuberculosis. The cell wall deficient variants of M. tuberculosis could be determined by the PCR of M. tuberculosis. It is recommended that the L-forms should be noticed during the treatment with the antituberculosis drugs and combination treatment with antituberculous drugs to which the L-forms were susceptible, is also very important.

Antitubercular Agents↗
PubMed2002

Pulmonary disease caused by Mycobacterium avium-intracellulare in HIV-negative patients: five-year follow-up of patients receiving standardised treatment.

SETTING AND OBJECTIVE: Previous reports on small numbers highlighted the need for a prospective study of the clinical features and response to treatment of pulmonary disease caused by Mycobacterium avium-intracellulare (MAC). DESIGN AND METHODS: Patients with two positive cultures were randomised to 2 years of rifampicin and ethambutol or of rifampicin, ethambutol and isoniazid. Clinical, bacteriological and radiological progress was monitored for 5 years. RESULTS: Seventy-five patients entered the study. They had a mean age of 64 years (range 29-87) and the sexes were balanced. Approximately two-thirds had previous/ co-existing lung disease(s). Sputum was positive on direct smear in 56%, and cavitation was observed in 61%, most having at least one large cavity. Just under half had bilateral disease and one-third extensive disease. Disease was confined to upper zone(s) in 25%. Twenty-seven (36%) died within 5 years, three because of MAC disease. There were 11 treatment failures and 10 relapses, with no correlation between those and in vitro resistance. Forty-five (60%) were alive at 5 years, of whom 23 were confirmed cured. CONCLUSION: Pulmonary disease caused by MAC is associated with high morbidity and mortality. Standard susceptibility tests do not correlate with the response of the disease to chemotherapy. Rifampicin and ethambutol, with or without isoniazid, cured 31%, a result comparable with or better than that found previously with more toxic regimens, but mortality (36%) remains high. More effective regimens are needed, and management of coexisting illnesses and general health needs to be to maximised.

Adult↗
PubMed1992

[Extracellular and intracellular activity of sparfloxacin against Mycobacterium avium complex and Mycobacterium xenopi].

Activity of the new fluoroquinolone sparfloxacin against 30 strains of M. avium complex and 25 strains of M. xenopi was tested in vitro. Sparfloxacin was used alone (determination of MICs and MBCs) and in combination with ethambutol and rifabutin. Synergy studies with determination of the FIC and FBC indices showed that the sparfloxacin-ethambutol combination was synergistic against 10 M. avium complex strains and 12 M. xenopi strains. With the three-drug combination (sparfloxacin-ethambutol-rifabutin), synergy was found against 12 M. avium and 14 M. xenopi strains. Studies of intracellular bacteria showed that the decrease in viable bacteria with the three-drug combination was 1 log for M. avium and 2 log for M. xenopi.

Acquired Immunodeficiency Syndrome↗
PubMed2003

Drug resistance in tuberculosis in Delhi: a 2 year profile (2001--2002).

234 isolates of Mycobacterium tuberculosis obtained from 1000 suspected cases of tuberculosis reporting at National Institute of Communicable Disease, Delhi for laboratory investigation between Jan 2001 to August 2002 were subjected to invitro drug sensitivity test against the first line drugs (Isoniazid, Streptomycin, Rifampicin, Ethambutol and Thiacetazone) by proportion method using Lowenstein Jensen (LJ) media. Out of 234 isolates of Mycobacterium tuberculosis, 142 were from cases of untreated tuberculosis, whereas only 92 isolates were from treated cases of tuberculosis. An initial drug resistance of 21.83% was seen against INH, 9.85% against Streptomycin, 15.49% against Rifampicin, 4.22% against ethambutol and 2.11% to thiacetazone. Multidrug resistance (MDR-i.e. Resistance to both INH and Rifampicin) was seen in 11.97% of isolates. 4(2.8%) isolates were found to be resistant to all drugs tested. A much higher level of acquired resistance was seen the figures being 61.95% for INH, 53.36% for rifampicin, 35.86% for streptomycin, 20.65% for ethambutol and 10.86% for thiacetazone. Avery high acquired MDR to the tune of 42.39% was seen. 24(26%) isolates were found to be resistant to all drugs tested. No significant difference were observed in the drug resistance pattern between pulmonary and extrapulmonary cases of tuberculosis in both initial and acquired drug resistance category.

Antitubercular Agents↗
PubMed2006

Scanning laser polarimetry in pulmonary tuberculosis patients on chemotherapy.

INTRODUCTION: The aim of this study was to analyse the thickness of the retinal nerve fibre layer (RNFL) of pulmonary tuberculosis patients on ethambutol and isoniazid. MATERIALS AND METHODS: This was a prospective cohort study where patients with newly diagnosed pulmonary tuberculosis requiring chemotherapy, including ethambutol and isoniazid, were imaged using scanning laser polarimetry. Their mean baseline RNFL thickness and various scanning laser polarimetry parameters of both eyes were measured 2 weeks after the commencement of chemotherapy. The measurements were repeated at 3 months and 6 months after treatment. The various parameters of the baseline and the follow-up measurements were compared using paired sample t-test with Bonferroni correction. RESULTS: Twenty-four patients (16 males and 8 females; mean age, 51.0 +/- 17.6 years) were recruited. There was no statistically significant difference between the baseline and the follow-up measurements in RNFL thickness and all other scanning laser polarimetry parameters. CONCLUSION: In this cohort of subjects, there was no subclinical change in RNFL thickness detected by scanning laser polarimetry in pulmonary tuberculosis patients on chemotherapy, including ethambutol and isoniazid, after 6 months of treatment.

Adult↗
PubMed1972

Rifampin.

Rifampin is a potent antituberculous drug. In the treatment of drug-resistant tuberculosis it is highly effective provided it is given in combination with other drugs to which the patient's organisms are sensitive. Rifampin and ethambutol is a particularly powerful combination and will achieve almost 100% sputum conversion. It seems likely that rifampin will replace streptomycin, and ethambutol will replace PAS in first-treatment cases. Optimum first-line treatment will thus consist of rifampin, INH and ethambutol, with the probability of almost 100% success and the possibility also that the total duration of treatment may be considerably reduced. Rifampin is well tolerated but it may give rise to liver dysfunction and thrombocytopenia in a small proportion of patients. Patients treated with rifampin must be kept under close supervision because of the risk of side effects and, more important, because irregular treatment may lead to the development of rifampin-resistant organisms.

Adult↗
PubMed1976

Short-course chemotherapy in pulmonary tuberculosis. A controlled trial by the British Thoracic and Tuberculosis Association.

A rigimen of rifampicin plus isoniazid, supplemented in the first two months by ethambutol or streptomycin, was given for six, nine, twelve, or eighteen months in a controlled study of 696 patients with culture-positive pulmonary tuberculosis. The results obtained in the thirty-three months since the start of treatment when all the patients in the six-month and nine-month groups had completed at least two years and those in the twelve-month group had completed twenty-one months of post-chemotherapy follow-up revealed no relapses among patients receiving nine months chemotherapy and a 1% relapse-rate in the twelve-month group. The same regimen given for only six months resulted in a relapse-rate of 5% during the subsequent twenty-seven months. There were adverse effects with streptomycin but not with ethambutol. It is concluded that treatment with rifampicin plus isoniazid for nine months, supplemented by ethambutol in a dose of 25 mg/kg for the first two months, is now acceptable as standard chemotherapy for pulmonary tuberculosis in Britain.

Adolescent↗
PubMed1994

Treatment of tuberculosis and tuberculosis infection in adults and children. American Thoracic Society.

1. A 6-mo regimen consisting of isoniazid, rifampin, and pyrazinamide given for 2 mo followed by isoniazid and rifampin for 4 mo is the preferred treatment for patients with fully susceptible organisms who adhere to treatment. Ethambutol (or streptomycin in children too young to be monitored for visual acuity) should be included in the initial regimen until the results of drug susceptibility studies are available, unless there is little possibility of drug resistance (i.e., there is less than 4% primary resistance to isoniazid in the community, and the patient has had no previous treatment with antituberculosis medications, is not from a country with a high prevalence of drug resistance, and has no known exposure to a drug-resistant case). This four-drug, 6-mo regimen is effective even when the infecting organism is resistant to INH. This recommendation applies to both HIV-infected and uninfected persons. However, in the presence of HIV infection it is critically important to assess the clinical and bacteriologic response. If there is evidence of a slow or suboptimal response, therapy should be prolonged as judged on a case by case basis. 2. Alternatively, a 9-mo regimen of isoniazid and rifampin is acceptable for persons who cannot or should not take pyrazinamide. Ethambutol (or streptomycin in children too young to be monitored for visual acuity) should also be included until the results of drug susceptibility studies are available, unless there is little possibility of drug resistance (see Section 1 above). If INH resistance is demonstrated, rifampin and ethambutol should be continued for a minimum of 12 mo. 3. Consideration should be given to treating all patients with directly observed therapy (DOT). 4. Multiple-drug-resistant tuberculosis (i.e., resistance to at least isoniazid and rifampin) presents difficult treatment problems. Treatment must be individualized and based on susceptibility studies. In such cases, consultation with an expert in tuberculosis is recommended. 5. Children should be managed in essentially the same ways as adults using appropriately adjusted doses of the drugs. This document addresses specific important differences between the management of adults and children. 6. Extrapulmonary tuberculosis should be managed according to the principles and with the drug regimens outlined for pulmonary tuberculosis, except for children who have miliary tuberculosis, bone/joint tuberculosis, or tuberculous meningitis who should receive a minimum of 12 mo of therapy.(ABSTRACT TRUNCATED AT 400 WORDS)

AIDS-Related Opportunistic Infections↗
PubMed1997

Quality assurance programme for drug susceptibility testing of Mycobacterium tuberculosis in the WHO/IUATLD Supranational Laboratory Network: first round of proficiency testing.

SETTING: Quality assurance of the WHO/IUATLD global tuberculosis drug resistance surveillance programme. OBJECTIVE: To perform a proficiency test of drug susceptibility procedures within the WHO/IUATLD network of supranational reference laboratories (SRL). DESIGN: Identical culture panels consisting of 20 clinical isolates of Mycobacterium tuberculosis containing both drug susceptible and drug resistant cultures were tested by the 16 laboratories of the network for resistance to streptomycin, isoniazid, rifampicin and ethambutol. The drug susceptibility testing procedures included the proportion, absolute concentration and resistance ratio methods as well as their variants, including the radiometric BACTEC 460 method. RESULTS: The first round of proficiency testing has shown that the specificity of drug susceptibility testing within the SRL network was significantly higher than its sensitivity. The testing of isoniazid and rifampicin shows a high degree of agreement between the labs, but discordant results can be obtained with streptomycin and ethambutol. CONCLUSION: Drug susceptibility procedures for the testing of isoniazid and rifampicin, the two anti tuberculosis drugs which define multidrug-resistant tuberculosis, are highly reliable within the SRL network. Procedures for drug susceptibility testing of streptomycin and ethambutol are still in need of standardization.

Antitubercular Agents↗
PubMed2000

[Drug resistance in Mycobacterium tuberculosis. A multicenter study of the Barcelona area. Grupo de Trabajo sobre Resistencias en Tuberculosis].

BACKGROUND: The aims of this multicenter study was to establish the level of primary and acquired drug resistance of M. Tuberculosis strains isolated in Barcelona and to identify possible risk groups using clinical data. PATIENTS AND METHODS: All tuberculosis patients with isolation and identification of M. tuberculosis strains from October 1995 to September 1997 were included. Susceptibility tests isoniazid, rifampin, ethambutol, streptomycin and pyrazinamide were performed using the Bactec 460 system and the proportions method on solid medium. Logistic progression was used for statistical analysis. RESULTS: The total number of patients included was 1,749 (1,535 non-treated and 214 previously treated). Primary drug resistance was 5.7% (isoniazid 3.8%; rifampin 1.0%, streptomycin 2.1%, ethambutol 0.3% and pyrazinamide 1.0%). Acquired drug resistance was 20.5% (isoniazid 17.3%, rifampin 9.8%, ethambutol 1.9%, streptomycin 4.7% and pyrazinamide 6.5%). Primary drug resistance was associated with people over 60 years old and women. CONCLUSIONS: The low level of drug resistance enables antituberculosis treatment of non-treated patients to start with the standardised three-drug regimes except in the case of foreign people from countries with a high level of drug resistance. Susceptibility tests are recommended on all M. tuberculosis strains isolated, together with controlled studies of drug resistance surveillance.

Adolescent↗
PubMed2001

Safety of an ofloxacin-based antitubercular regimen for the treatment of tuberculosis in patients with underlying chronic liver disease: a preliminary report.

BACKGROUND AND AIMS: Hepatotoxicity is a major side-effect of antitubercular drugs (ATD). As these drugs are metabolized in the liver, there is a theoretical risk of increased hepatotoxicity in patients with underlying chronic liver disease (CLD). Ofloxacin has antitubercular activity and has exclusive renal clearance. The aim was to study the efficacy and safety of an ofloxacin-based antitubercular regimen for treating tuberculosis in patients with underlying CLD. METHODS: Thirty-one cases were randomly assigned to two drug regimens using WHO dosage schedules: (i) regimen A (n = 15): isoniazid, rifampicin and ethambutol for 2 months, followed by isoniazid and rifampicin for a further 7 months; and (ii) regimen B (n = 16): isoniazid, pyrazinamide, ethambutol and ofloxacin for 2 months, followed by isoniazid, ethambutol and ofloxacin for a further 10 months. Hepatotoxicity was diagnosed if alanine aminotransferase/aspartate aminotransferase increased > fivefold from the baseline or to > 400 IU/L, or if bilirubin increased by > 2.5 mg/dL from the baseline. RESULTS: The response to ATD was achieved in all the patients who completed the therapy. Four (26.6%) patients on regimen A developed hepatotoxicity as compared to none on regimen B (P = 0.043). None of these patients could be restarted on ATD using the same regimen A because of the persistently deranged liver functions. CONCLUSIONS: In patients with tuberculosis who have underlying CLD: (i) an ofloxacin-based antitubercular regimen without rifampicin is as effective as a rifampicin-based regimen; and (ii) a combination of isoniazid with rifampicin is more hepatotoxic than a combination with ofloxacin and pyrazinamide.

Adolescent↗
PubMed2001

Progressive rise of Mycobacterium tuberculosis resistance to rifampicin and streptomycin in Riyadh, Saudi Arabia.

OBJECTIVE: The aim of this study was to investigate, for the first time, the factors associated with resistance to antituberculous drugs in Saudi Arabia, and to follow the long-term trends in drug resistance. METHODOLOGY: A retrospective study of patients with positive Mycobacterium tuberculosis recorded at the Riyadh Tuberculosis Center in 1990 was undertaken. The resistance figures from the same centre for the period July 1996 to June 1997 were reviewed for comparison. RESULTS: Resistance was significantly higher in those previously treated (71%) than in those who denied previous treatment (34%). There was a trend towards association of resistance with cavitatory, multilobar, and acid fast bacilli-positive cases. Nationality (Saudis, Yemenis, others) had no significant effect on resistance. The Riyadh Region now has the same high prevalence of rifampicin resistance as previously reported in the Western Region of the Kingdom. The figures on resistance for the years 1986-88, 1990, and 1996-97 were: isoniazid 19.5/13.8/11.1%, rifampicin 10/20.7/24.6%, streptomycin 5/22/27.4%, ethambutol 3.7/3.9/1.8%, respectively. The reduction in isoniazid and ethambutol resistance coincided with a rise in resistance to rifampicin and streptomycin. We speculate that this resulted from the fact that isoniazid and ethambutol are restricted only to the treatment of tuberculosis and cannot, by law, be dispensed by general practitioners or private pharmacies. Rifampicin and streptomycin, however, are widely used for brucellosis; an endemic disease in Saudi Arabia where up to 12 weeks of rifampicin therapy is recommended. CONCLUSIONS: There has been a significant increase in rifampicin and streptomycin resistance in Saudi Arabia over the last 10 years. Possible causes include poor compliance and wide use of these two drugs for non-tuberculosis conditions. These findings could jeopardize the benefits of the directly observed therapy short course policy which is being implemented in Saudi Arabia. Consideration should be given to prohibiting the routine use of rifampicin for the treatment of brucellosis.

Adult↗