Ocular toxicity of ethambutol

OBJECTIVE

To review the literature on ocular toxicity of ethambutol--its background, clinical presentation, toxicity characteristics, management, monitoring, and preventive measures.

DATA SOURCES

Literature search of Medline from 1962 to May 2005.

STUDY SELECTION

All related literature in English using the search formula: (ethambutol OR myambutol) AND (eye* OR ophthal* OR ocular) AND (adverse OR toxic).

DATA EXTRACTION

All information was collected and analysed by authors.

DATA SYNTHESIS

Ethambutol hydrochloride is a commonly used first-line anti-tuberculous agent. Although rare, ocular toxicity in the form of optic neuritis (most commonly retrobulbar neuritis) has been well documented since its first use in the 1960s. Classically described as dose- and duration-related and reversible on therapy discontinuation, reversibility of optic neuritis remains controversial. International guidelines on prevention and early detection of ethambutol-induced ocular toxicity have been published. Nonetheless, opinion of the clinical effectiveness of regular vision tests to enable early detection of toxicity is divided.

CONCLUSIONS

The course of ethambutol-induced ocular toxicity is unpredictable. Measures to ensure a high level of awareness in medical staff and patients of this potential adverse effect appear to be the best current preventive method. Classified by the World Health Organization as a place with an intermediate tuberculosis burden and good health infrastructure, Hong Kong is in a good position to examine the unanswered questions about ethambutol-induced ocular toxicity.

Multidrug-resistant tuberculous spondylodiscitis: need for aggressive management and drug susceptibility testing of Mycobacterium tuberculosis isolates

A 49-year-old woman complaining of thoracic spine pain for 18 months was admitted to the hospital for evaluation. Magnetic resonance imaging of the thoracic spine showed spondylodiscitis of the T8-T9 intervertebral disk. Computed tomography scan-guided fine needle aspiration of the affected area was performed but it did not reveal the cause of the disease. Because of continuing symptoms and lack of diagnosis the patient underwent a vertebrectomy and substitution of the eighth thoracic vertebra with Moss titanium cylinder filled-up with auto-bone grafts. Culture of the extracted bone grew Mycobacterium tuberculosis, which was resistant to isoniazid and rifampin. Persistent and even invasive diagnostic work up is needed for the proper and prompt management of patients with spondylodiscitis.

Comparison of intermittent ethambutol with rifampicin-based regimens in HIV-infected adults with PTB, Kampala

BACKGROUND

The human immunodeficiency virus (HIV) is a key factor responsible for the high rates of tuberculosis (TB) in sub-Saharan Africa. Treatment of TB with rifampicin (R, RMP) containing short-course regimens is highly effective in HIV-infected adults. We conducted a study to compare the efficacy and safety of intermittent ethambutol (E, EMB) with two RMP-containing regimens to treat pulmonary TB in HIV-infected patients.

SETTING

National Tuberculosis Treatment Centre, Mulago Hospital, Kampala, Uganda.

DESIGN

This was a prospective cohort compared to two non-randomised control groups. The study group and the two control arms were treated with 2 months of isoniazid (H), RMP, pyrazinamide (Z) and EMB followed by 6 E3H3 for the study group and 4HR or 6HR for controls.

RESULTS

Between April 1993 and March 2000, 136 patients were enrolled in the 2EHRZ/E3H3 arm, 147 in the 2EHRZ/4HR arm and 266 in the 2EHRZ/6HR arm. The relapse rate was 18.2 per 100 person-years observation (PYO) for the study regimen compared to 9.7/100 PYO (P = 0.0063) and 4.8/100 PYO (P = 0.0001) in patients treated with 2 EHRZ/4HR or 2EHRZ/6HR, respectively.

CONCLUSION

The 2EHRZ/6E3H3 regimen is safe and effective but has a significant risk of relapse.

[Cervical spondylodiscitis: one pathogen may hide another]

A 54-year-old man presented with tuberculous spondylodiscitis associated to E. coli found in an intervertebral disc space needle biopsy. The enterobacteria came from a cholecystitis. The patient was cured by medical treatment, consisting in a non-surgical immobilization, antitubercular quadritherapy in association with a specific antibiotic treatment. No other case of spondylodiscitis caused by a mycobacterial coinfection pathogen has been reported so far.

High hepatotoxicity of pyrazinamide and ethambutol for treatment of latent tuberculosis

Pyrazinamide (PZA) combined with either ethambutol (EMB) or a fluoroquinolone for 6-12 months is one of the treatments recommended for latent tuberculosis infection (LTBI) in contacts exposed to multidrug-resistant tuberculosis (MDR-TB). The aim of the present study was to describe the side effects related to combined PZA and EMB treatment given for LTBI, in contacts previously exposed to MDR-TB. In total, 12 consecutive contacts, all of African origin and aged 38+/-5 yrs, were treated with daily PZA (23+/-4 mg.kg(-1)) and EMB (17+/-4 mg.kg(-1)) at Geneva University Hospital outpatient clinic (Switzerland), as a result of contact-tracing procedures for two patients with contagious MDR-TB. Clinical status and liver function tests (aspartate aminotransferase (ALAT) and alanine aminotransferase (ASAT)) were monitored monthly. In seven cases (58%) treatment was discontinued after a median of 119 days, due to hepatic toxicity in six cases (ALAT or ASAT elevation more than four times the upper normal limit), and gastrointestinal symptoms in one case. In conclusion, combined pyrazinamide and ethambutol for latent tuberculosis infection may be associated with a high risk of hepatic toxicity, and warrants close monitoring. There is clearly a need for alternative preventive treatments for contacts exposed to multidrug-resistant tuberculosis.

[Case of endometrial tuberculosis]

A 66-year-old woman was referred to our hospital because of lochiorrhea. Uterus MRI and ultrasonography showed hydrometra. Endometrium biopsy revealed epithelioid cell granuloma, and vaginal discharge and endometrium culture was positive for M. tuberculosis. She was diagnosed as endometrial tuberculosis. After treatment with INH, RFP, and EB for 9 months, she recovered.

[Tuberculoma complicating tuberculous meningitis: description of one paediatric case]

Intracranial tuberculoma is a possible complication of meningeal, miliary or pulmonary tuberculosis. In developing countries it represents 30% of space-occupying intracranial lesions, in industrialised countries only 0.1-0.2%. One recently recognised phenomenon is the development ex novo or the enlargement of the tuberculoma during antitubercular chemo-antibiotic therapy. Here we report the clinical case of an immunocompetent Italian baby girl who presented an intracranial tuberculoma during tuberculous meningitis. We underline how such an event is possible, the need for early neuroradiological evaluation and its favourable course, maintaining adequate antitubercular therapy associated with steroid therapy.

[A case of Mycobacterium intracellulare lung disease that was detected by health examination and was successfully cured by chemotherapy--including discussions on the diagnostic criteria of the disease]

A case was 56 years old woman, and she did not have any subjective symptom. She received multiphasic health screening, and abnormal shadow was detected on her chest radiograph. Chest radiography revealed infiltrations in the middle lobe. Computed tomography (CT) of the thorax showed clusters of small nodules in the middle lobe. The bronchial washing specimen showed acid-fast bacilli identified as Mycobacterium intracellulare by DNA-DNA hybridization (DDH) method. This case was diagnosed as Mycobacterium intracellulare lung disease. The patient received combination therapy with rifampicin, ethambutol, and clarithromycin for one year with radiological improvement. CT findings were characteristic and useful for the early diagnosis of MAC infection, which led to cure of the disease by chemotherapy.

[Procedure in case of suspected mycobacterial infection of lymph nodes of the neck. 2. Therapy]

In the treatment of tuberculosis the patients normally receive a two month daily treatment with Isoniazid, Rifampicin, Pyrazinamid and Ethambutol, followed by a daily treatment with Isoniazid and Rifampicin for four month. The atypical mycobacterial infections can be addressed as a local infection and are amendable to surgical therapy, eventually followed by a daily treatment with antibiotics for four to twelve weeks. In Germany it is obligatory to inform the local public health department about typical mycobacterial infections. Hygiene procedures following German law are discussed in this review.

Ethambutol Ocular Toxicity in Treatment Regimens forMycobacterium aviumComplex Lung Disease

Ethambutol (EMB) is an important component of multidrug treatment regimens for Mycobacterium avium complex lung disease. Ocular toxicity is the most important potential EMB toxicity, especially in the elderly population with M. avium complex lung disease. Two hundred twenty-nine patients with M. avium complex lung disease, 55% women and 53% with nodular/bronchiectatic disease, received a mean of 16.1 +/- 10.8 months of multidrug therapy that included EMB. Fifty patients (22%) were known to have preexisting ocular disease. While on EMB, 97 (42%) patients consulted an opthalmologist and 24 (10%) stopped EMB at least temporarily. Eight of 139 patients (6%) on daily therapy were diagnosed with EMB ocular toxicity, whereas 0 of 90 patients on intermittent therapy had EMB ocular toxicity (p = 0.05). All patients with EMB ocular toxicity developed symptoms between outpatient clinic appointments; none were diagnosed with routine visual acuity and color vision testing. All patients with EMB ocular disease returned to baseline ocular status after discontinuation of EMB. Intermittent EBM administration was associated with less ocular toxicity than daily EMB administration in this patient population.

Establishment of a reference formulation for bioequivalence assessment of rifampicin-containing FDCs: an essential step towards improving tuberculosis treatment

SETTING

Selection of a reference product for bioequivalence studies of rifampicin (RMP) in prequalifying fixed-dose combinations (FDC) for worldwide distribution through the WHO is critical.

OBJECTIVE

To investigate the feasibility of establishing FDC formulations as reference products for bioequivalence studies of RMP in prequalification programmes.

DESIGN

A biostudy was conducted as an open, two-period randomised cross-over trial. Two three-drug FDCs containing RMP, isoniazid and ethambutol hydrochloride were administered to a group of 22 volunteers with a wash-out period of 1 week. Plasma samples were collected and analysed for the concentration of RMP and desacetyl-RMP, a major active metabolite of RMP, up to 24 h. Pharmacokinetic parameters of RMP were calculated: Cmax, AUC0-24, Tmax, kel and absorption efficiencies.

RESULTS

No significant difference was observed between the administered formulations with respect to the major pharmacokinetic parameters Cmax, Tmax and AUC0-24 when evaluated by parametric (two-way ANOVA) and non-parametric (Hauschke's analysis) statistical analysis. The concentration of RMP falls within the reported acceptable therapeutic range.

CONCLUSION

FDCs can be developed as a reference product for bioequivalence studies.

Pharmacodynamics and pharmacokinetics of SQ109, a new diamine-based antitubercular drug

SQ109 is a novel [1,2]-diamine-based ethambutol (EMB) analog developed from high-throughput combinatorial screening. The present study aimed at characterizing its pharmacodynamics and pharmacokinetics. The antimicrobial activity of SQ109 was confirmed in vitro (Mycobacterium tuberculosis-infected murine macrophages) and in vivo (M. tuberculosis-infected C57BL/6 mice) and compared to isoniazid (INH) and EMB. SQ109 showed potency and efficacy in inhibiting intracellular M. tuberculosis that was similar to INH, but superior to EMB. In vivo oral administration of SQ109 (0.1-25 mg kg(-1) day(-1)) to the mice for 28 days resulted in dose-dependent reductions of mycobacterial load in both spleen and lung comparable to that of EMB administered at 100 mg kg(-1) day(-1), but was less potent than INH at 25 mg kg(-1) day(-1). Monitoring of SQ109 levels in mouse tissues on days 1, 14 and 28 following 28-day oral administration (10 mg kg(-1) day(-1)) revealed that lungs and spleen contained the highest concentration of SQ109, at least 10 times above its MIC. Pharmacokinetic profiles of SQ109 in mice following a single administration showed its C(max) as 1038 (intravenous (i.v.)) and 135 ng ml(-1) (p.o.), with an oral T(max) of 0.31 h. The elimination t(1/2) of SQ109 was 3.5 (i.v.) and 5.2 h (p.o.). The oral bioavailability was 4%. However, SQ109 displayed a large volume of distribution into various tissues. The highest concentration of SQ109 was present in lung (>MIC), which was at least 120-fold (p.o.) and 180-fold (i.v.) higher than that in plasma. The next ranked tissues were spleen and kidney. SQ109 levels in most tissues after a single administration were significantly higher than that in blood. High tissue concentrations of SQ109 persisted for the observation period (10 h). This study demonstrated that SQ109 displays promising in vitro and in vivo antitubercular activity with favorable targeted tissue distribution properties.

Enlarged cervical lymph nodes and elevated liver chemistry tests: a therapeutic dilemma

We describe the case of a 36-years-old male patient, originating from India, who presented with enlarged cervical lymph nodes and elevated liver chemistry tests. Histologically necrosing granulomas were observed in the lymph nodes, and PCR revealed DNA from mycobacterium tuberculosis. However, in the liver biopsy granulomatous hepatitis without central necrosis was seen. With a positive PCR for mycobacteria from liver tissue and no evidence for other hepatic diseases we started drug treatment with standard quadruple regimen consisting of isoniazid, rifampicin, ethambutol, and pyrazinamide. Five days after onset of therapy, liver chemistry tests rose 10-fold, forcing us to interrupt treatment. Gradual step-wise re-exposition with the same medication after return of liver chemistry tests to baseline was well tolerated without any further side effects. Liver involvement of tuberculosis can have many facets and may be treated by gradual dosing of standard drugs.

[Two cases of Mycobacterium szulgai pulmonary disease in the elderly]

The rate of pulmonary nontuberculous mycobacteriosis (NTM) in the total pulmonary mycobacteriosis has been continuously increasing. While M. avium complex is the most common cause of NTM, there are a few case reports of pulmonary infection due to M. szulgai. We described two cases of pulmonary NTM caused by M. szulgai. A 75-year-old male was admitted to our hospital because of dyspnea on effort, and productive cough. A chest X-ray showed an infiltrative shadow with cavity in the right upper lobe. A sputum smear for mycobacteria was positive, and a culture grew M. szulgai which was identified by DNA-DNA hybridization. He was treated with isoniazid, rifampicin, and ethambutol. His symptoms and CT and X-ray findings improved, and his sputum smear and culture converted to negative for mycobacteria. Second case was a 73-year-old male who had previously been diagnosed as MAC and pulmonary aspergillosis, and had been treated with antituberculous and antifungal drugs. He was readmitted to our hospital, because of general fatigue and hemoptysis. A chest X-ray revealed a consolidation with bronchiectasis and cavity in the both upper lung fields. A sptum smear for mycobacteria was positive, and a grown culture was identified as M. szulgai. He was treated with rifampicin, ethambutol and kanamycin based on the results of susceptibility testing. After 3 months of this treatment his sputum smear and culture converted to negative for mycobacteria, and his symptoms, and CT and X-ray findings improved.

Treatment outcome of multidrug-resistant tuberculosis among Vietnamese immigrants

OBJECTIVE

To review the outcome for MDR-TB treatment among potential migrants from Vietnam.

SETTING

All cases of documented MDR-TB treated by the International Organization of Migration (IOM) in Vietnam from 1989 to 2000 were reviewed.

METHODS

MDR-TB was defined as isoniazid- and rifampicin-resistant Mycobacterium tuberculosis. All cases of TB treated by the IOM and recorded in the computerised database were reviewed to identify MDR-TB cases. Demographics, chest radiograph results, drug resistance, drug use and dosage, duration of treatment, and outcome were analysed.

RESULTS

Forty-four cases of MDR-TB were identified. Treatment consisted of ambulatory directly observed treatment with an 8-drug protocol: isoniazid, rifampicin, pyrazinamide, ethambutol, capreomycin, ethionamide, ofloxacin and cycloserine. This initial protocol was modified due to drug availability or drug intolerance. Patients were treated with a median of 8 drugs (range 6-12). Mean duration of treatment for MDR-TB was 23.0 (SD+/-11.4) months. Thirty-eight (86%) patients were cured and emigrated, one failed treatment (2%), three were lost to follow-up (7%) and two died (4%).

CONCLUSION

Treatment for MDR-TB provided by the IOM was effective in preparing a low-income population for migration.

Adverse drug reactions observed during DOTS

A total of 8.37% of the 1195 patients treated at NDTB Centre with DOTS under RNTCP between January 2002 to June 2003 presented with adverse drug reactions. Patients showing any sort of adverse reactions were studied in detail by personal interviews and a semi-structured questionnaire. The profile of patients presenting with adverse reactions showed that majority of the patients (53%) had gastrointestinal reactions, the commonest presenting complaint being nausea and vomiting. General aches and pains were complained by about 35% and giddiness was the presenting complaint in 27% irrespective of the use of streptomycin, although giddiness was observed more often in Category II patients (59%). Skin rash and itching was complained by about 17% of patients and 11% complained of arthralgia, while only 1% had hepatotoxicity during treatment. Majority of the adverse reactions (67%) were observed within the first four weeks of treatment and only 0.25% of patients treated with DOTS had interruption of treatment for short periods.

Two 8-month regimens of chemotherapy for treatment of newly diagnosed pulmonary tuberculosis: international multicentre randomised trial

BACKGROUND

A WHO-recommended 8-month regimen based on ethambutol and isoniazid was evaluated in a randomised clinical trial against a 6-month standard regimen.

METHODS

1355 patients with newly diagnosed smear-positive pulmonary tuberculosis were randomly assigned one of three regimens: daily ethambutol, isoniazid, rifampicin, and pyrazinamide for 2 months, followed by ethambutol and isoniazid for 6 months (2EHRZ/6HE); the same drugs but given three times weekly in the initial intensive phase (2[EHRZ]3/6HE); or the same initial intensive phase as the first regimen, followed by 4 months of daily rifampicin and isoniazid (2EHRZ/4HR). Follow-up was to 30 months after the start of chemotherapy. Sputum was regularly examined by microscopy and culture. Unfavourable outcome was defined as failure during treatment or relapse afterwards. Analyses were by intention to treat.

FINDINGS

At 2 months, a significantly higher proportion of patients assigned the daily intensive phase than of those assigned the three-times-weekly regimen were culture negative (700/828 [85%] vs 333/433 [77%], p=0.001). 12 months after the end of chemotherapy, the proportions of unfavourable outcomes were 36 of 346 (10%) with 2EHRZ/6HE, 48 of 351 (14%) with 2(EHRZ)3/6HE, and 17 of 347 (5%) with 2EHRZ/4HR. Both 8-month regimens were significantly inferior to the control 6-month standard regimen (difference between control and 2EHRZ/6HE 5.5% [95% CI 1.6 to 9.4]; between control and 2(EHRZ)3/6HE 8.8% [4.5 to 13.0]). Adverse effects leading to interruption of treatment for 7 days or longer occurred in 28 patients (12 2EHRZ/6HE, five 2[EHRZ]3/6HE, 11 2EHRZ/4HR).

INTERPRETATION

The results of this study must be taken into account in recommendations on management of new cases of smear-positive tuberculosis.

[Case of pulmonary tuberculosis in late stage of pregnancy]

A 28-year-old woman who was a nurse was admitted to our hospital because her sputum was positive for M. tuberculosis. She was pregnancy of 35 weeks. First, she was administered INH, RFP, PZA and was treated with cesarean section on the 21st day after starting tuberculosis chemotherapy. The operation was done in operating room of negative pressure ventilation. The patient returned to the tuberculosis ward, and the newborn infant entered to a newborn nursery room after confirming negative tubercle bacilli in amnionic fluid by PCR examination. EB was added to the regimen of chemotherapy after childbirth. In general hospitals, infection control is an important issue as seen in this case.

[Miss-management in treatment failure of pulmonary tuberculosis]

PURPOSE

To investigate the risk factor of treatment failure of pulmonary tuberculosis excluding multi-drug resistant cases from the standpoint of both clinical management and tuberculosis control.

OBJECT AND METHOD

Retrospective chart review of patients who admitted to Fukujuji Hospital for treatment failure of pulmonary tuberculosis excluding multi-drug resistant cases from Jan. 1993 to Dec. 2003.

RESULTS

Out of 24 treatment failure cases available for analysis, 4 cases were associated with chronic tuberculous empyema with broncho-pleural fistula, and among them, chronic empyema was considered to be the main cause of treatment failure in one case. In 6 cases, poor adherence to medication was confirmed or suspected, and 2 of these 6 cases was also associated with miss-management. In 9 cases miss-management was found without poor adherence or chronic empyema, and in 8 out of these 9 cases, miss-management was considered to be the main cause of treatment failure. In 5 cases no apparent risk factor was found, but in 2 out of these 5 cases the ignorance of the results of drug sensitivity tests (and, therefore, miss-management) was strongly suspected. Summing up, in 10 out of 24 cases (41.7%), the miss-management was considered to be the main cause of treatment failure, and it was more frequently seen than poor adherence to medication.

CONCLUSION

Clinicians should be aware of these risk factors of treatment failure such as chronic empyema, weak regimen in bacteriological negative cases, rifampicin+ethambutol regimen, and miss-management of drug adverse effect. From the standpoint of tuberculosis control in Japan we considered that, in addition to DOT, strategy to secure the quality of tuberculosis treatment is by all means needed.

[Pulmonary Mycobacterium fortuitum infection with multiple nodular shadows in a healthy man]

We report a case of pulmonary Mycobacterium fortuitum infection with multiple nodular shadows. A 52 year-old male was admitted complaining of fever and chest abnormal shadows. He didn't have pulmonary or systemic underlying diseases. Chest radiograph and computed tomography scan showed multiple nodular shadows in the both lung fields. Isoniazid, rifampicin and ethambutol were administered based on the presumptive diagnosis of tuberculosis. Cultures of the sputum and bronchial washing fluid were repeatedly positive for M. fortuitum, and the case was diagnosed as pulmonary M. fortuitum infection. Although the in vitro susceptibility was resistant to isoniazid, rifampicin and ethambutol, abnormal shadows on the X-ray showed improvement by the combined use of INH, RFP and EB. There are no signs of recurrence after completion of the treatment for 12 months.

The activity of grepafloxacin in two murine models of Mycobacterium avium infection

The activity against Mycobacterium avium complex (MAC) of varying doses of grepafloxacin (GRE; 25 mg/kg, 50 mg/kg, 100 mg/kg, and 200 mg/kg) were compared to clarithromycin (CLA; 100 mg/kg and 200 mg/kg), ethambutol (EMB; 100 mg/kg), and rifabutin (RBT; 10 mg/kg) using an intranasal (IN) infection model compared to an intravenous (IV) infection model. Beige mice (C57BL6/J-Lyst bg J/+) were infected intranasally with about 10(6) organisms and for the IV model about 10(7) organisms. Treatment for both models was started 1 week postinfection and given by gavage 5 days/week for 4 weeks. At the initiation of therapy, an early control group was killed to determine the initial organism load. Three days following the completion of therapy, drug-treated groups of mice and the late control group were killed and the response to therapy measured. The most effective agents were CLA and RBT. GRE and EMB had modest activities in both the IN and the IV models. A matched comparison between IN and IV challenges for each of the agents used revealed greater suppression of MAC in the IN model compared to the IV model.

Split-drug regimens for the treatment of patients with sputum smear-positive pulmonary tuberculosis--a unique approach

OBJECTIVE

To evaluate the efficacy of split-drug regimens for treatment of patients with sputum smear-positive pulmonary tuberculosis in south India.

DESIGN

Randomized controlled clinical trial where eligible patients were randomly allocated to: (i) 2RE(3)HZ(3)(alt)/4RH(2) (split I): rifampicin plus ethambutol given on one day and isoniazid plus pyrazinamide the next day for first 2 months followed by rifampicin plus isoniazid twice weekly for 4 months, or (ii) 3RE(3)HZ(3)(alt)/3RH(2) (split II): similar to regimen 1, except duration was 3 months in each phase, or (iii) 2REHZ(3)/4RH(2) (control): rifampicin, isoniazid, ethambutol and pyrazinamide, given thrice weekly for 2 months followed by isoniazid and rifampicin twice weekly for 4 months. All patients were followed up clinically and bacteriologically every month up to 2 years and every 6 months for up to 5 years.

RESULTS

A favourable response (cultures negative for Mycobacterium tuberculosis during the last 2 months of treatment) was observed in 91% of 407 patients in split I, 94% of 415 in split II and 89% of 418 in the control regimen. Ninety-one per cent of 370 patients in split I, 93% of 389 in split II and 90% of 370 in control regimens had quiescent disease at the end of 60 months. Gastrointestinal symptoms were more frequent under the control regimen (P = 0.01).

CONCLUSION

Split-drug regimens were as effective as the control regimen in terms of favourable response at the end of treatment and quiescent disease at 5 years, and caused fewer gastrointestinal side-effects.

[A case of successful desensitization therapy for isoniazid-induced pneumonitis]

A 65-year-old man was admitted to hospital for treatment of pulmonary tuberculosis. He was treated with isoniazid (INH), rifampicin (RFP), ethambutol (EB), and pyrazinamide (PZA). On the 14th day, he developed a fever and interstitial pneumonia, which improved promptly after discontinuation of the antituberculous drugs. Drug lymphocyte stimulation tests against INH, RFP and PZA were negative. However, the provocation test on INH (only) was positive, leading to a diagnosis of pneumonitis caused by INH. We then tried desensitization of INH over a period of two weeks, which was successful and occurred without any clinical event. In the past, five cases of INH-induced pneumonitis were reported, but desensitization of INH did not occur in any. We conclude that physicians should be aware not only of paradoxical reactions but also of drug-induced pneumonitis when a new pulmonary infiltrate develops in the course of tuberculosis treatment. Furthermore, drug desensitization may be possible in some cases of drug-induced pneumonitis.

Development of a liposome formulation of ethambutol

A liposomal formulation capable of encapsulating 76 to 92% of the antimycobacterial drug ethambutol and showing prolonged in vitro release kinetics is described. In vitro efficacy is equivalent to that of the free drug, suggesting that encapsulation of ethambutol has the potential to shorten the current regimens for tuberculosis.

Prescriptions and dosages of anti-tuberculosis drugs in the National Tuberculosis Control Programme of Malawi

SETTING

All 44 non-private hospitals in Malawi treating pulmonary tuberculosis (PTB) patients with an oral regimen (0.5RHZE/1.5R3H3Z3E3/6HE).

OBJECTIVES

In new smear-positive PTB patients, to determine whether: 1) numbers of tablets were correctly prescribed according to pre-treatment weights, and 2) medication dosages were adequate, too low or too high.

DESIGN

Retrospective review of TB registers and TB treatment cards for patients registered with new smear-positive PTB between 1 October and 31 December 2001.

RESULTS

Of 1970 patients aged > or = 15 years, 1211 (62%) had treatment cards and pre-treatment weights. Incorrect prescriptions were given to 88 (7%), and many of these received dosages of anti-tuberculosis drugs that were too high or too low. For those receiving correct prescriptions, daily treatment in the initial and continuation phases was generally associated with adequate dosages of drugs. However, in the initial intermittent phase, between 3% and 40% of patients received anti-tuberculosis drug dosages that were too low.

CONCLUSION

A small percentage of patients receive incorrect prescriptions, which can be resolved by training and supervision. In those receiving correct prescriptions, intermittent treatment provides dosages that are sometimes too low. Weight bands for intermittent treatment should be re-examined.

[Cardiac tamponade with paroxysmal atrial flutter controlled by antituberculous therapy]

We report a rare and unique case of possible extrapulmonary tuberculosis in an 83-year-old man who had cardiac tamponade and paroxysmal atrial flutter. The patient was admitted to our hospital because of syncope. The cardiac tamponade and paroxysmal atrial flutter were treated by pericardiocentesis and drainage of bloody pericardial fluid. Mycobacterium tuberculosis was not detected in diagnostic specimens, nor was any evidence of malignancy found. The remarkable elevation of adenosine deaminase and the predominance of lymphocytes in the pericardial fluid, considering the past history of tuberculosis, led to a diagnosis of extrapulmonary tuberculosis. After receiving standard antituberculous therapy by ethambutol, isoniazid, and rifampicin, the patient recovered and has remained well up to the present day. Thirty-six months have passed since his recovery without the recurrence of cardiac tamponade or any other cardiac events.

Comparison of clinical features in patients with pulmonary Mycobacterium-avium complex (MAC) disease treated before and after proposal for guidelines

We aimed to investigate the transitional pattern of the clinical features of pulmonary Mycobacterium-avium complex (MAC) disease, especially with regard to the clinical effect of treatment, in patients treated before and after the implementation of the 1998 guidelines of the Japanese Society for Tuberculosis for combined chemotherapy for pulmonary MAC disease. The clinical findings and treatments of 220 patients with pulmonary MAC disease during the past 10 years were compared by dividing the patients into two groups, each encompassing a 5-year period. During the past 5 years, we have carried out combined chemotherapy with rifampicin, ethambutol, an aminoglycoside (streptomycin or kanamycin), and clarithromycin (CAM) following the guidelines for the treatment of pulmonary MAC disease proposed in 1998, and we have achieved positive results; both the sputum conversion rate and clinical improvement of the outcome in patients with primary infectious type rose significantly. Although there were no significant differences in the background or in microbiological and radiological findings in the two groups, significant improvement was seen in the sputum conversion rate and in improvement of the clinical effect of treatment. The results of this combined chemotherapy were unsatisfactory, however, when compared with its clinical effect on pulmonary tuberculosis. Therefore, we anticipate the development of new companion drugs for pulmonary MAC disease that are as active as CAM.

[Efficiency of an intensive stage of chemotherapy for tuberculosis in elderly and senile patients]

A hundred new cases of active pulmonary tuberculosis whose age was 60 to 87 years were treated by the intensive chemotherapy regimen recommended by the WHO. Most (n = 78) patients satisfactorily tolerated the intensive stage, fully completed the regimen, and made up a study group (Group 1). Group 2 comprised the remaining 22 patients who had, due to its poor tolerance, to transfer to their individual regimen. The higher incidence of significant cardiovascular diseases in Group 2 patients is the only significant difference between these two identified groups. The advantages of the standard chemotherapy regimen are the more rapid elimination of symptoms of tuberculous intoxication; the earlier and more frequent disappearance of Mycobacterium tuberculosis from the sputum even with the primary drug resistance of the causative agent; as well as a more frequent closure of decay cavities. The findings make it possible to recommend a wider use of the standard intensive chemotherapy regimens for elderly and senile patients with tuberculosis.

[Use of lymphotropic therapy in the multimodality treatment of patients with pulmonary tuberculosis and comorbidity]

Regional lymphotropic therapy involving 10% isoniazid administration was included into multimodality treatment in 250 patients with pulmonary tuberculosis and comorbidity. The findings have indicated that the lymphotropic therapy during the use of rifampicin, streptomycin, ethambutol enhances the efficiency of chemotherapy in different forms of pulmonary tuberculosis, including the latter concurrent with hepatic lesion or diabetes mellitus. Lymphotropic therapy is particularly beneficial to patients with poor drug tolerability. The use of lymphotropic isoniazid in the multimodality treatment of pulmonary tuberculosis leads to the earlier disappearance of the symptoms of tuberculous intoxication (by 1-1.5 months) in 80-92% of the patients, to abacillation in the same periods, to the increased frequency of decay cavity closure by an average of 15% as compared to the conventional treatment, and, in most cases, to the normalization of the biochemical parameters of hepatic function.

Septische Lockerung eines Wagner-Revisionsschaftes durch Mycobacterium tuberculosis

Only a few cases of specific tuberculous infections of total hip arthroplasties have been published. We report the case of a 66-year-old male patient who received a cementless total hip arthroplasty due to osteoarthritis of the left hip in 1990. Four years later, revision arthroplasty with a Wagner revision stem was performed because of aseptic loosening. In 1995 revision of a loosened acetabular cup was necessary. In 1996 we saw the patient for the first time in our outpatient unit. He complained of increasing pain in the region of the left hip. X-rays showed loosening of the Wagner stem. Aspiration of the synovial fluid of the left hip revealed an infection with mycobacterium tuberculosis (radioimmunoassay). There were no signs of tuberculous infection in the patient's history. Treatment consisted of removal of the prosthesis followed by antituberculosis chemotherapy for 12 months with rifampicin, ethambutol, isoniazid, and pyrazinamide. In April 2001 revision of the left hip joint and implantation of a MRP titanium revision stem and reconstruction of the acetabulum with an acetabular reconstruction ring was done. Until today the patient exhibits no signs of recurrence of the tuberculous infection.

[Tuberculous pneumonia in children]

Tuberculosis (TB) is one of the most common infectious diseases worldwide. Data from WHO show that one third of the world population is estimated to be infected with Mycobacterium Tuberculosis (TM). TB remains an important problem for adults and children in Lithuania as number of new diagnosed children's TB cases vary between 16.7-21.8 per 100 000 population. The aim of this article is to present the TB pneumonia in childhood: peculiarities of clinical forms, symptoms, diagnostics, treatment and results. The diagnosis of TB in children more often is made on epidemiological data, supposed by clinical symptoms, tuberculin skin test and chest radiography results, rather than bacteriological data. Clinical symptoms of TB pneumonia are mostly similar to atypical pneumonia, caused by Mycoplasma pneumoniae and Chlamydia pneumoniae. We discussed similarities and differences between atypical and TB pneumonia, based on 10-year data of our patient ill with atypical and TB pneumonia, (123 - 63.7%) and (69 - 36.3%) respectively. Chemotherapy of TB is directed towards the eradication of TM. The main principle of TB chemotherapy is regular, directly controlled and long-term usage of several antituberculous drugs. The child, ill with TB, is totally cured, when he has no clinical symptoms or laboratory findings specific for TB and is able to return to his normal social life. Two clinical cases of children ill with TB pneumonia are discussed as well. We hope that this article and two clinical cases would remind pediatricians and family doctors to be aware of still possible TB in childhood.

[Remission of pulmonary alveolar proteinosis during antituberculosis chemotherapy]

The patient was a 32-year-old man in whom pulmonary tuberculosis had occurred 5 years after the presumptive onset of pulmonary alveolar proteinosis. A diagnosis of pulmonary tuberculosis was made by sputum smears positive for acid-fast bacilli. Computer tomography of the chest showed ground glass opacities, consolidation and cavitation. Rifampicin, isoniazid and ethambutol were given daily, and streptomycin three times a week. Serial chest radiographs revealed progressive clearing not only of the new but also of the old lung infiltrates thought to be due to pulmonary alveolar proteinosis. Serum LDH and CEA returned to normal values. This case indicates the possibility of improving pulmonary alveolar proteinosis by tuberculosis infection or antituberculosis therapy.

The clearance of theophylline is increased during the initial period of tuberculosis treatment

OBJECTIVE

To evaluate the effects of combined anti-tuberculosis treatment including isoniazid (INH), rifampicin (RMP), ethambutol (EMB) and pyrazinamide (PZA), on the pharmacokinetics of theophylline during the initial phase of treatment.

DESIGN

Prospective, controlled clinical study.

PATIENTS AND METHODS

Twenty patients with pulmonary tuberculosis received 7.35 mg/kg/day of aminophylline intravenously combined with anti-tuberculosis agents. The first theophylline serum concentration was measured before administration of INH, RMP, EMB and PZA, and samples were obtained once daily for 6 consecutive days after initiation of treatment. All patients in this study were non-smokers with normal hepatic and renal function, and they were not given any other drugs that could affect the clearance of theophylline.

RESULTS

The concentration and half-life of theophylline was decreased and its clearance was increased significantly at days 5-7 after administration of antituberculosis agents compared to before the therapy was started.

CONCLUSIONS

These results suggest that patients with asthma or chronic obstructive pulmonary disease administered combinations of anti-tuberculosis agents and theophylline during the initial phase of tuberculosis treatment should be monitored closely for changes in theophylline concentration, and that the dose of theophylline should be adjusted accordingly.

[Acquired circinated ichthyosis revealing a lymph node tuberculosis]

BACKGROUND

Acquired ichthyosis usually reveals or is associated with an internal disease. The classical clinical aspect is vulgaris ichthyosis. We report a case of acquired ichthyosis, presenting original clinical features, revealing a lymph node tuberculosis.

CASE REPORT

A 63-year-old male patient without past history of skin disease consulted for a generalized eruption. The eruption was composed of multiple erythemato-squamous plaques. The edge of the plaque was raised and circinated. Histologic examination of the edge and the centre of the lesion supported the clinical diagnosis of ichthyosis. The diagnosis of lymph node tuberculosis based on large inguinal nodes was confirmed by the fast acid-bacilli found in the lymph node. Initiation of antituberculosis therapy was followed by the rapid and complete disappearance of the skin lesions.

DISCUSSION

We report a case of acquired ichthyosis with original clinical features and we propose to coin the term "acquired circinated ichthyosis". This entity was clinically distinct from ichthyosis vulgaris or pityriasis rotunda. This dermatosis was concomitant to lymph node tuberculosis and healed under antituberculosis therapy.

Bactericidal and sterilizing activities of antituberculosis drugs during the first 14 days

Colony-forming units of Mycobacterium tuberculosis in sputum were counted at 2-day intervals in 100 patients treated with 22 regimens of isoniazid, rifampin, pyrazinamide, ethambutol, or streptomycin, given alone or in combinations. The exponential fall in colony-forming units was measured by linear regression coefficients of the log counts during the initial 2-day phase of rapid, drug-determined killing and during the subsequent 12 days of much slower sterilizing activity. The regression coefficients during the first 2 days varied significantly according to the drug; the greatest effects in multiple regression analyses were due to isoniazid (p < 0.001) and rifampin (p = 0.027). The rapid kill obtained with isoniazid was unaffected by addition of other drugs, so that a change in activity after adding an unknown drug to isoniazid would not be measurable. In multiple regression analysis of the coefficients during Days 2-14, rifampin and streptomycin had significant effects (p = 0.007 and 0.006, respectively), indicating that both drugs had important sterilizing activity, streptomycin particularly early. Isoniazid and pyrazinamide had no significant effects. In analyses of combined drug regimens only, ethambutol had an effect (p = 0.01) in reverse direction to that of rifampin, suggesting it antagonized the sterilizing activity of other drugs.

[An adult case of tuberculous meningitis]

A 36-year-old man was referred to our hospital with complaints of high fever and headache. A diagnosis of miliary tuberculosis with tuberculous meningitis was made. He was treated with isoniazid (400 mg/day), rifampicin (300 mg/day), ethambutol (750 mg/day), pyrazinamide (1.0 g/day) and prednisolone (60 mg/day). However, he lost consciousness because of hydrocephalus on the second day of hospitalization. Emergency cerebrospinal fluid drainage improved his neurological symptoms. After two months, he again complained of headache with nausea and double vision. Numerous tuberculomas were found not only in the cerebrum but also in the liver, the spleen and the retina. Recurrent hydrocephalus was treated with a V-P shunt, and combination therapy with four antituberculous agents was maintained for 18 months. He was discharged in a healthy condition, although a mild left facial palsy remained. In addition, we examined the inflammatory cytokine levels in both the CSF and the serum over the period of the patient's hospitalization. We concluded that the cytokine levels in the CSF may be associated with the progress and the prognosis of tuberculous meningitis.

A pilot stability study on four-drug fixed-dose combination anti-tuberculosis products

A pilot stability study was carried out on four fixed-dose combination anti-tuberculosis products at 40 degrees C and 75% RH. The strip-packed products were stable, while the blister-packed products showed both physical and chemical changes. The products in unpacked conditions showed severe (approximately 60%) decomposition of rifampicin and extensive physical changes. The main decomposition product in the solid state was isonicotinyl hydrazone of 3-formylrifamycin and isoniazid. It is suggested that attention should be paid to the detection and quantitation of this product in the marketed formulations. The packing material used in the manufacture of FDC products should also be of the highest quality.

Pharmaceutical formulation of a fixed-dose anti-tuberculosis combination

SETTING

Department of Pharmacy and Pharmacology, University of the Witwatersrand. Despite the availability of highly effective treatment regimens for tuberculosis (TB), the cure rate still remains relatively low. This may be attributed to the high incidence of patient non-compliance, which subsequently leads to the emergence of multidrug-resistant TB (MDR-TB). To avoid the problem of further creation and propagation of MDR-TB, it may be proposed that patients should be given fixed-dose combinations of anti-tuberculosis drugs whenever self-administration is permitted.

OBJECTIVE

To optimise an anti-tuberculosis extemporaneous powder formulation for suspension in order to develop a fixed combination of rifampicin, isoniazid, pyrazinamide and ethambutol hydrochloride as a powder to be reconstituted with water by the patient prior to administration.

METHODS

Different suspending agents were evaluated for their influence on powder flow properties, and sediment volume on the powder blends. Sodium starch glycolate was selected as the suspending agent because of its favourable powder flow properties and sediment volume produced. The dissolution characteristics of the extemporaneous powder for suspension were also compared to the dissolution profiles of commercially available anti-tuberculosis tablet dosage forms.

RESULTS

The powder for suspension for rifampicin, isoniazid, pyrazinamide and ethambutol hydrochloride all compared favourably to the dissolution rate from the commercially available tablet dosage forms.

[Assessment of the use of a multicomponent drug in the treatment of new cases of pulmonary tuberculosis]

The multicomponent drug Mairin-P that contains isoniazid, 60 mg, rifampicin, 120 mg, pyrazinamide, 300 mg, and ethambutol hydrochloride, 225 mg, has been pharmacokinetically and clinically studied. There was no significant difference in the pharmacokinetic parameters of rifampicin as a component of Mairin-P and in combination with antitubercuous agents as free dosage forms. Treatment of first detected patients with pulmonary tuberculosis who isolate drug-sensitive Mycobacterium tuberculosis with Mairin-P is as effective as conventional treatment regimens with antituberculous drugs. Adverse reactions, including non-correctable one, due to the use of Mairin-P occur less frequently than to that of antituberculous drugs.

Study of drug resistance in previously treated tuberculosis patients in Gujarat, India

SETTING

Department of Tuberculosis and Chest Diseases and State Tuberculosis Diagnosis and Training Centre (STDTC), a DOTS centre in Ahmedabad, Gujarat State, India. The study was carried out by retrospectively reviewing patient data between January 2000 and August 2001.

OBJECTIVE

To evaluate the pattern of drug resistance among previously treated tuberculosis patients who remained symptomatic or smear-positive despite receiving anti-tuberculosis drugs under DOTS for a minimum of 5 months.

DESIGN

A total of 1472 pulmonary tuberculosis patients who had taken anti-tuberculosis treatment were evaluated retrospectively with respect to their drug resistance pattern by sputum culture for acid-fast bacilli (AFB) and sensitivity testing with isoniazid, rifampicin, streptomycin and ethambutol (E).

RESULT

Of the 1472 patients evaluated, 804 (54.6%) were treatment failure cases and 668 (45.4%) were relapse cases; 822 patients (373 failure and 449 relapse) were culture-positive. Of these 822 patients, 482 (58.64%, 261 failure and 221 relapse) were resistant to one or more drugs. Resistance to one drug was observed in 86 patients (10.46%), to two drugs in 149 (18.13%), to three drugs in 122 (14.84%) and to four drugs in 125 (15.21%). Single drug resistance was most commonly seen with isoniazid (62 patients, 7.5%), followed by streptomycin (12 patients, 1.4%), rifampicin (eight patients, 0.97%) and ethambutol (four patients, 0.4%). Resistance to isoniazid plus rifampicin alone was seen in 76 patients (9.2%).

CONCLUSION

Drug resistance is a major problem in the treatment of pulmonary tuberculosis. Detection of drug resistance patterns and treatment with second-line anti-tuberculosis drugs in appropriate regimens are necessary in the treatment of failure and relapse cases in order to reduce the emergence of multidrug-resistant tuberculosis.

Results of a 12-month regimen for drug-resistant pulmonary tuberculosis

SETTING

Several therapeutic regimens for drug-resistant tuberculosis have been suggested, most of them with a total duration of 18-24 months.

OBJECTIVE

To report our experience using a shorter regimen.

DESIGN

Fifty patients with drug-resistant pulmonary tuberculosis were managed by withdrawing all anti-tuberculosis drugs until the results of a drug sensitivity test were obtained (approximately 3 months), and then a 12-month self-administered regimen with four to six anti-tuberculosis drugs at full daily doses was initiated, based primarily on the sensitivity test and secondarily on the history of previous treatment.

RESULTS

In 31 patients treatment was completed as planned, in six it was irregular and 13 definitively abandoned it. In the best scenario, 90.3% (28/31) of patients with full treatment were cured; this outcome was similar for both multidrug-resistant (MDR, n = 18, 88.9%) and non-MDR (n = 13, 92.3%) patients. Six months later, the relapse rate was 4.8%, and after a 5-year follow-up 14 out of 18 cured patients who were located remained asymptomatic (77.8%). If the worst scenario was applied, a 62.0% cure rate (31/50) was obtained.

CONCLUSIONS

A 12-month regimen with a minimum of four anti-tuberculosis agents at full dose, essentially selected on drug sensitivity testing, could be an alternative option for the treatment of drug-resistant pulmonary tuberculosis.

Bioequivalence assessment of rifampicin, isoniazid and pyrazinamide in a fixed dose combination of rifampicin, isoniazid, pyrazinamide and ethambutol vs. separate formulations

Depending on the patient category, tuberculosis requires treatment with 3 to 5 drugs which means that patient's compliance to therapy may not be optimal. To increase patient's adherence to treatment schedules, these drugs can be given as single drug preparations or fixed dose combinations (FDCs) of 2 or more drugs in a single formulation. However, an important issue associated with a rifampicin-containing FDC is its quality. Hence, to avoid spurious formulations entering the market, the World Health Organization and the International Union Against Tuberculosis and Lung Disease have recommended FDCs only of proven bioavailability. In this study, the relative bioavailability of rifampicin, isoniazid and pyrazinamide was assessed in a group of 14 healthy male subjects using the FDC tablet containing 4 drugs versus separate formulations at the same dose levels. The study was designed as an open, crossover trial. A total of 9 blood samples were collected over a period of 24 h. The concentration of rifampicin, its main metabolite desacetyl rifampicin, isoniazid and pyrazinamide in plasma were assessed using HPLC analysis. The pharmacokinetic parameters AUC(0-24) and Cmax were subjected to parametric and non-parametric statistical tests at 90% confidence interval. In addition, time to reach peak concentration (tmax), elimination rate constant (Kel) and terminal elimination half-life (t1/2) for each drug were also calculated. It was concluded that the FDC tablet containing 4 drugs is bioequivalent to separate rifampicin, isoniazid and pyrazinamide formulations at the same dose levels.