Cutaneous adverse drug reactions to anti-tuberculosis drugs: state of the art and into the future

Clinical management of anti-tuberculosis related cutaneous adverse drug reactions based on reintroduction

The prevalence of anti-tuberculosis related adverse cutaneous reactions is around 1%. The most frequent reaction is exanthema, then urticaria and drug rash with eosinophilia and systemic symptoms (DRESS). Sequential drug reintroduction helped identifying rapidly the main culprit drug with good outcome. Rifampicin and pyrazinamide were the two most culprit drugs. DRESS was attributable to ethambutol and rifampicin.

Cutaneous drug reaction secondary to antitubercular regimen: A case report from Nepal

Cutaneous adverse drug reactions are known side effects of first-line antitubercular therapy, which ranges from mild pruritus to life-threatening toxic epidermal necrolysis. Severe cutaneous adverse drug reactions can lead to antitubercular therapy discontinuation and further complicates tuberculosis treatment. Here we present the case of a 49-year-old obese male who developed a generalized maculopapular rash within 24 hours of initiation of therapy followed by bullae over palms in 3 days. Antitubercular therapy was immediately discontinued, and he was managed with antihistamines, intravenous fluid, and electrolyte supplementation. He was discharged on antihistamines, a short course of systemic steroids, moxifloxacin, and bedaquiline (second-line antitubercular therapy (ATT)). Proper guidelines about rechallenge therapy will enormously aid in managing cutaneous adverse drug reactions, and efficient treatment of tuberculosis in these patients, and ceasing its progression to multisystemic complications. This article aims to discuss the presentation and management of cutaneous adverse drug reactions in the setting of Nepal.

Skin infiltrating T-cell profile of drug reaction with eosinophilia and systemic symptoms (DRESS) reactions among HIV-infected patients

Introduction

Drug Reaction with Eosinophilia Systemic Symptoms (DRESS) is more common in persons living with HIV (PLHIV), and first-line anti-TB drugs (FLTDs) and cotrimoxazole are the commonest offending drugs. Limited data is available on the skin infiltrating T-cell profile among DRESS patients with systemic CD4 T-cell depletion associated with HIV.

Materials and methods

HIV cases with validated DRESS phenotypes (possible, probable, or definite) and confirmed reactions to either one or multiple FLTDs and/or cotrimoxazole were chosen (n = 14). These cases were matched against controls of HIV-negative patients who developed DRESS (n = 5). Immunohistochemistry assays were carried out with the following antibodies: CD3, CD4, CD8, CD45RO and FoxP3. Positive cells were normalized to the number of CD3+ cells present.

Results

Skin infiltrating T-cells were mainly found in the dermis. Dermal and epidermal CD4+ T-cells (and CD4+/CD8+ ratios) were lower in HIV-positive vs. negative DRESS; p < 0.001 and p = 0.004, respectively; without correlation to whole blood CD4 cell counts. In contrast, no difference in dermal CD4+FoxP3+ T-cells was found in HIV-positive vs. negative DRESS, median (IQR) CD4+FoxP3+ T-cells: [10 (0-30) cells/mm² vs. 4 (3-8) cells/mm², p = 0.325]. HIV-positive DRESS patients reacting to more than one drug had no difference in CD8+ T-cell infiltrates, but higher epidermal and dermal CD4+FoxP3+ T-cell infiltrates compared to single drug reactors.

Conclusion

DRESS, irrespective of HIV status, was associated with an increased skin infiltration of CD8+ T-cells, while CD4+ T-cells were lower in HIV-positive DRESS compared to HIV-negative DRESS skin. While inter-individual variation was high, the frequency of dermal CD4+FoxP3+ T-cells was higher in HIV-positive DRESS cases reacting to more than one drug. Further research is warranted to understand the clinical impact of these changes.

Unraveling the Secrets Behind the Multidrug-Resistant Tuberculosis Treatment Outcome in Chronic Renal Failure Patients Requiring Hemodialysis: A Systematic Review

Multidrug-resistant/rifampicin-resistant tuberculosis (MDR/RR TB) is a global concern, with 450,000 new cases and 191,000 deaths in 2021. TB and chronic kidney disease (CKD) have been associated since 1974, with suggested explanations such as oxidative stress, malnutrition, dysfunction in vitamin D metabolism, and a compromised cell-mediated immune response. End-stage renal failure patients are more likely to acquire drug resistance due to poor adherence, adverse drug reactions, and inappropriate dose adjustment. We then aim to evaluate the therapeutic outcome of multidrug-resistant TB of the lungs in patients who require hemodialysis in terms of successful treatment (cured and treatment completed) and the associated factors for a favorable outcome. Our secondary goal is to identify unfavorable treatment outcomes (treatment failed, patient died, or patient lost to follow-up) and the underlying associated factors. We conformed to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 Guidelines for this systematic review. We included adults (>19 years old) with chronic kidney disease who needed hemodialysis and had microbiologically confirmed multidrug-resistant pulmonary TB, excluding patients who had a renal allograft transplant, were on peritoneal dialysis, had extrapulmonary TB, were children and pregnant patients. We searched PubMed, MEDLINE, PubMed Central, ScienceDirect, Public Library of Science (PLOS), and Google Scholar. Keywords were combined with the Boolean "AND" operator to gather results as well as the medical subject heading (MeSH) search strategy. After screening study articles by reading their titles and abstracts, the following tools were used to assess the risk of bias: the Newcastle-Ottawa scale for observational studies, the Assessment of Multiple Systematic Reviews (AMSTAR) checklist for systematic reviews, and the Joanna Briggs Institute (JBI) assessment tool for case reports. Primary and secondary outcomes were assessed, and a conclusion was made. We gathered 21,570 studies from the databases between 2013 and 2023, with 30,062 total participants. There were eight eligible studies for review. Patients with CKD, particularly those on dialysis, are at increased risk of TB due to a combination of factors that contribute to immunosuppression. TB reactivation is common in chronic renal failure patients. Diagnostic samples such as sputum and pleural fluid had lower sensitivity rates compared to tissue samples, which led to delays in diagnosis and treatment and, most importantly, contributed to drug resistance. All new dialysis patients should undergo interferon-gamma release assay testing. TB-infected patients with severe renal disease (eGFR 30 ml/min) had increased morbidity and mortality; however, the use of directly observed treatment, short-course (DOTS), and renal-dose adjustment of anti-TB medications significantly reduced these risks. Drug-induced hepatitis and cutaneous reactions were common adverse effects of anti-TB medications. A therapeutic drug monitoring guideline is required to reduce these adverse events and even mortality. Additional research is required to assess the safety and efficacy of therapeutic regimens, as well as their outcomes, in this population with multidrug-resistant TB.

HIV-Associated Immune Dysregulation in the Skin: A Crucible for Exaggerated Inflammation and Hypersensitivity

Skin diseases are hallmarks of progressive HIV-related immunosuppression, with severe noninfectious inflammatory and hypersensitivity conditions as common as opportunistic infections. Conditions such as papular pruritic eruption are AIDS defining, whereas delayed immune-mediated adverse reactions, mostly cutaneous, occur up to 100-fold more during HIV infection. The skin, constantly in contact with the external environment, has a complex immunity. A dense, tightly junctioned barrier with basal keratinocytes and epidermal Langerhans cells with antimicrobial, innate-activating, and antigen-presenting functions form the frontline. Resident dermal dendritic, mast, macrophage, and innate lymphoid cells play pivotal roles in directing and polarizing appropriate adaptive immune responses and directing effector immune cell trafficking. Sustained viral replication leads to progressive declines in CD4 T cells, whereas Langerhans and dermal dendritic cells serve as viral reservoirs and points of first viral contact in the mucosa. Cutaneous cytokine responses and diminished lymphoid populations create a crucible for exaggerated inflammation and hypersensitivity. However, beyond histopathological description, these manifestations are poorly characterized. This review details normal skin immunology, changes associated with progressive HIV-related immunosuppression, and the characteristic conditions of immune dysregulation increased with HIV. We highlight the main research gaps and several novel tissue-directed strategies to define mechanisms that will provide targeted approaches to prevention or treatment.

Tuberkulose im Erwachsenenalter

Die Tuberkulose ist in Deutschland eine seltene, überwiegend gut behandelbare Erkrankung. Weltweit ist sie eine der häufigsten Infektionserkrankungen mit ca. 10 Millionen Neuerkrankungen/Jahr. Auch bei einer niedrigen Inzidenz in Deutschland bleibt Tuberkulose insbesondere aufgrund der internationalen Entwicklungen und Migrationsbewegungen eine wichtige Differenzialdiagnose. In Deutschland besteht, aufgrund der niedrigen Prävalenz der Erkrankung und der damit verbundenen abnehmenden klinischen Erfahrung, ein Informationsbedarf zu allen Aspekten der Tuberkulose und ihrer Kontrolle. Diese Leitlinie umfasst die mikrobiologische Diagnostik, die Grundprinzipien der Standardtherapie, die Behandlung verschiedener Organmanifestationen, den Umgang mit typischen unerwünschten Arzneimittelwirkungen, die Besonderheiten in der Diagnostik und Therapie resistenter Tuberkulose sowie die Behandlung bei TB-HIV-Koinfektion. Sie geht darüber hinaus auf Versorgungsaspekte und gesetzliche Regelungen wie auch auf die Diagnosestellung und präventive Therapie einer latenten tuberkulösen Infektion ein. Es wird ausgeführt, wann es der Behandlung durch spezialisierte Zentren bedarf.

Die Aktualisierung der S2k-Leitlinie „Tuberkulose im Erwachsenenalter“ soll allen in der Tuberkuloseversorgung Tätigen als Richtschnur für die Prävention, die Diagnose und die Therapie der Tuberkulose dienen und helfen, den heutigen Herausforderungen im Umgang mit Tuberkulose in Deutschland gewachsen zu sein.

IFN-γ ELISpot in Severe Cutaneous Adverse Reactions to First-Line Antituberculosis Drugs in an HIV Endemic Setting

Severe cutaneous adverse reactions related to first-line antituberculosis drugs are associated with high mortality and long-term morbidity. Oral sequential drug challenge, as a form of drug provocation testing, helps to salvage therapy by identifying culprit drugs but is associated with risk and is costly. IFN-γ enzyme-linked immune absorbent spot (ELISpot), an adjunctive in vitro diagnostic tool, may help to guide risk-stratification approaches. To determine the diagnostic accuracy of IFN-γ ELISpot against full-dose sequential drug challenge, we analyzed samples collected prospectively at multiple time points in 32 patients with first-line antituberculosis drug‒associated severe cutaneous adverse reaction (81% HIV infected, 25 with drug reaction with eosinophilia and systemic symptoms, and 7 with Stevens‒Johnson syndrome/toxic epidermal necrolysis). Sensitivity of IFN-γ ELISpot was 33% (4 of 12), 13% (1 of 8), 11% (1 of 9), and 0% (0 of 4) for rifampicin, isoniazid, pyrazinamide, and ethambutol, respectively (positivity threshold ≥50 spot forming units/million cells). Specificity was 100% for all the four drugs. Rifampicin IFN-γ ELISpot sensitivity increased to 58% (7 of 12) if a threshold of 20 spot forming units was used and to 75% (3 of 4) when restricted to samples <12 weeks after acute severe cutaneous adverse reaction event; specificity remained 100% for both. IFN-γ ELISpot offers adequate risk stratification of rifampicin severe cutaneous adverse reaction using acute samples and lowered threshold for positivity. Given the low sensitivity of IFN-γ ELISpot for other first-line antituberculosis drugs, additional optimization is needed to improve risk-stratification potential.

Tuberculosis treatment-related lichenoid drug eruptions

Tuberculosis is one of the leading causes of death from infectious diseases in adults worldwide. Drug hypersensitivity in tuberculosis is an important problem affecting the treatment process. Although treatment is started with isoniazid, rifampicin, ethambutol, and pyrazinamide in drug-sensitive tuberculosis patients, it may not always be continued in this way. When hypersensitivity develops under antituberculosis treatment, type 4 hypersensitivity is the most common, and maculopapular drug eruption develops as a subgroup. Lichenoid drug eruption is very rare. We present our case who was diagnosed with pulmonary tuberculosis, who developed lichenoid drug eruption while receiving treatment, and whose treatment was completed by giving the new regimen with successful desensitization.

Clinical standards for the dosing and management of TB drugs

BACKGROUND: Optimal drug dosing is important to ensure adequate response to treatment, prevent development of drug resistance and reduce drug toxicity. The aim of these clinical standards is to provide guidance on 'best practice´ for dosing and management of TB drugs.METHODS: A panel of 57 global experts in the fields of microbiology, pharmacology and TB care were identified; 51 participated in a Delphi process. A 5-point Likert scale was used to score draft standards. The final document represents the broad consensus and was approved by all participants.RESULTS: Six clinical standards were defined: Standard 1, defining the most appropriate initial dose for TB treatment; Standard 2, identifying patients who may be at risk of sub-optimal drug exposure; Standard 3, identifying patients at risk of developing drug-related toxicity and how best to manage this risk; Standard 4, identifying patients who can benefit from therapeutic drug monitoring (TDM); Standard 5, highlighting education and counselling that should be provided to people initiating TB treatment; and Standard 6, providing essential education for healthcare professionals. In addition, consensus research priorities were identified.CONCLUSION: This is the first consensus-based Clinical Standards for the dosing and management of TB drugs to guide clinicians and programme managers in planning and implementation of locally appropriate measures for optimal person-centred treatment to improve patient care.

'Practical management of suspected hypersensitivity reactions to anti-tuberculosis drugs.'

Tuberculosis (TB) is the commonest cause of death by a single infectious agent globally and ranks amongst the top ten causes of global mortality. The incidence of TB is highest in Low-Middle Income countries (LMICs). Prompt institution of, and compliance with, therapy are cornerstones for a favourable outcome in TB and to mitigate the risk of multiple drug resistant (MDR)-TB, which is challenging to treat. There is some evidence that adverse drug reactions (ADRs) and hypersensitivity reactions (HSRs) to anti-TB drugs occur in over 60% and 3-4% of patients respectively. Both ADRs and HSRs represent significant barriers to treatment adherence and are recognised risk factors for MDR-TB. HSRs to anti-TB drugs are usually cutaneous and benign, occur within few weeks after commencement of therapy and are likely to be T-cell mediated. Severe and systemic T-cell mediated HSRs and IgE mediated anaphylaxis to anti-TB drugs are relatively rare, but important to recognise and treat promptly. T-cell mediated HSRs are more frequent amongst patients with co-existing HIV infection. Some patients develop multiple sensitisation to anti-TB drugs. Whilst skin tests, patch tests and in vitro diagnostics have been used in the investigation of HSRs to anti-TB drugs, their predictive value is not established, they are onerous, require specialist input of an allergist and are resource-dependent. This is compounded by the global, unmet demand for allergy specialists, particularly in low income countries (LICs) / LMICs and now the challenging circumstances of the SARS-CoV-2 pandemic. This narrative review provides a critical analysis of the limited published evidence on this topic and proposes a cautious and pragmatic approach to optimise and standardise the management of HSRs to anti-TB drugs. This includes clinical risk stratification and a dual strategy involving sequential re-challenge and rapid drug desensitisation. Furthermore, a concerted international effort is needed to generate real-time data on ADRs, HSRs, safety and clinical outcomes of these interventions.

High occurrence of simultaneous multiple-drug hypersensitivity syndrome induced by first-line anti-tuberculosis drugs

Background

Multiple drug hypersensitivity syndrome (MDHS) results in treatment delay or failure and often results in severe drug hypersensitivity reactions. There are few reports of MDHS in response to anti-tuberculosis drugs; however, clinical information is scarce. Understanding the frequency and clinical characteristics of simultaneous MDHS against first-line anti-tuberculosis drugs in patients with non-severe drug hypersensitivity reactions is necessary.

Methods

We reviewed 27 patients with drug fever or maculopapular exanthem in response to first-line anti-tuberculosis drugs between January 2010 and June 2019. Drug fever or maculopapular exanthem occurred when isoniazid, rifampin, ethambutol, and pyrazinamide were administered simultaneously. Drug provocation tests for the 4 drugs were performed to identify the culprit drugs.

Results

All patients showed positive reactions to 1 or more drugs. MDHS was diagnosed in 13 (48%) patients, of whom 11 and 2 patients reacted to 2 and 3 drugs, respectively. In comparison to the patients with single-drug hypersensitivity, the patients with MDHS did not exhibit any differences in characteristics. Ethambutol and rifampin were the common drugs that induced a reaction, and the combination of these 2 drugs induced MDHS most frequently. Among the patients with MDHS, there were no differences between the drugs that caused drug fever and maculopapular exanthem. All patients with MDHS were successfully treated with alternative drugs.

Conclusions

Simultaneous MDHS may occur frequently in patients with drug fever or maculopapular exanthem caused by first-line anti-tuberculosis drugs, indicating the need to evaluate the allergy responses for all 4 drugs, even in patients without severe drug hypersensitivity. The combination of ethambutol and rifampin was the most common trigger that induced MDHS.

Delabeling Delayed Drug Hypersensitivity: How Far Can You Safely Go?

Delayed immune-mediated adverse drug reactions (IM-ADRs) are defined as reactions occurring more than 6 hours after dosing. They include heterogeneous clinical phenotypes that are typically T-cell-mediated reactions with distinct mechanisms across a wide spectrum of severity from benign exanthems through to life-threatening cutaneous or organ-specific diseases. For mild reactions such as benign exanthem, considerations for delabeling are similar to immediate reactions and may include a graded or single-dose drug challenge with or without preceding skin or patch testing. Evaluation of challenging cases such as the patient who is on multiple drugs at the time a severe delayed IM-ADR occurs should prioritize clinical ascertainment of the most likely phenotype and implicated drug(s). Although not widely available and validated, procedures such as patch testing, delayed intradermal skin testing, and laboratory-based functional drug assays or genetic (human leukocyte antigen) testing may provide valuable information to further help risk stratify patients and identify the likely implicated and/or cross-reactive drug(s). The decision to use a drug challenge as a diagnostic or delabeling tool in a patient with a severe delayed IM-ADR should weigh the risk-benefit ratio, balancing the severity and priority for the treatment of the underlying, and the availability of alternative efficacious and safe treatments.

Severe Cutaneous Adverse Reactions to Anti-tuberculosis Drugs in Korean Patients

Purpose

Anti-tuberculosis drugs (ATDs) can cause severe cutaneous adverse reactions (SCARs) such as Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and drug reaction with eosinophilia and systemic symptoms (DRESS). Underlying tuberculous infection and co-administration of multiple drugs may contribute to the complexity of ATD-related SCARs. This study aimed to investigate the clinical characteristics and outcomes of ATD-related SCARs.

Methods

We analyzed ATD-related SCAR cases in 2010-2015, selected from a web-based Database of the Korean Registry of SCAR.

Results

Among 783, 53 patients with ATD-induced SCARs were enrolled, including 12 with SJS/TEN (22.6%) and 41 with DRESS (77.4%). When comparing the ATD and non-ATD groups, the prevalence of DRESS patients was higher in the ATD group than in the non-ATD group (77.4% vs. 45.8%, P < 0.001). Among patients with ATD-related SCARs, those with SJS/TEN were significantly older, had higher intensive care unit admissions, and had higher mortality than those with DRESS (70.5 vs. 50.0 years, P < 0.001; 41.7% vs. 6.1%, P = 0.010; and 33.3% vs. 2.5%, P = 0.003, respectively). ATDs were challenged in 14 cases. The ATD associated most often with SCAR cases was rifampin (81.8%), followed by isoniazid (66.7%), ethambutol (50.0%), pyrazinamide (33.3%). Six patients (42.9%) had hypersensitivity reactions to 2 or more drugs.

Conclusions

DRESS was more common among the ATD-related SCAR cases. Although treatment with most ATDs carries the risk of SCAR development, the use of rifampin was most frequently involved in the occurrence of SCARs. Multiple hypersensitivity was frequently observed in ATD-related SCARs.

Pyrazinamide enhances lipid peroxidation and antioxidant levels to induce liver injury in rat models through PI3k/Akt inhibition

Pyrazinamide (PZA) is an anti-tuberculosis drug known to causes liver injury. phosphatidylinositol-3-kinase/protein kinase B (PI3K/Akt) signaling protects against liver injury by promoting cellular antioxidant defenses and reducing intracellular reactive oxygen species (ROS) and lipid peroxidation. The regulatory mechanisms and functions of PI3K/Akt signaling during the hepatotoxicity of PZA are however not fully understood. Rats were administered PZA or/and the PI3K activator (740Y-P) for 7 days. The levels of serum parameters were examined via standard enzymatic techniques and the pathological status of the liver was confirmed by H & E staining. The levels of lipid peroxidation and antioxidant production were determined using commercial kits. Liver apoptosis was assessed by TUNEL staining. The expression of apoptosis-related proteins and PI3K/Akt signaling were assessed by western blot analysis. PZA treatment significantly increased serum alanine transaminase, aspartate transaminase, gamma-glutamyl transpeptidase and tall bilirubin leading to liver damage in rats. PZA also facilitated lipid peroxidation and suppressed antioxidant defenses. PZA led to apoptotic induction in rat liver cells through the downregulation of Bcl-2 and the upregulation of Bax and caspase-3. PZA also dramatically inhibited PI3K/Akt signaling in rat liver cells. We further verified that PI3K/Akt signaling in response to 740Y-P could attenuate hepatic injury, lipid peroxidation and apoptosis in rat liver cells in response to PZA. We reveal that PZA-induced liver injury in rats occurs through PI3k/Akt signaling, the recovery of which prevents liver injury in rat models.

Treatment of Drug-Susceptible Tuberculosis

Mycobacterium tuberculosis is a major public health concern and requires prompt treatment. Goals of treatment include curing the individual patient and protecting the community from ongoing tuberculosis transmission. To achieve durable cure, regimens must include multiple agents given concurrently and in a manner to ensure completion of therapy. This article focuses on preferred regimens of drug-susceptible tuberculosis under current guidelines by the American Thoracic Society, Centers for Disease Control and Prevention, and Infectious Diseases Society of America and World Health Organization. In addition, topics including patient centered care, poor treatment outcomes, and adverse effects are also discussed.

Safety implications of combined antiretroviral and anti-tuberculosis drugs

Introduction: Antiretroviral and anti-tuberculosis (TB) drugs are often co-administered in people living with HIV (PLWH). Early initiation of antiretroviral therapy (ART) during TB treatment improves survival in patients with advanced HIV disease. However, safety concerns related to clinically significant changes in drug exposure resulting from drug-drug interactions, development of overlapping toxicities and specific challenges related to co-administration during pregnancy represent barriers to successful combined treatment for HIV and TB.Areas covered: Pharmacokinetic interactions of different classes of ART when combined with anti-TB drugs used for sensitive-, drug-resistant (DR) and latent TB are discussed. Overlapping drug toxicities, implications of immune reconstitution inflammatory syndrome (IRIS), safety in pregnancy and research gaps are also explored.Expert opinion: New antiretroviral and anti-tuberculosis drugs have been recently introduced and international guidelines updated. A number of effective molecules and clinical data are now available to build treatment regimens for PLWH with latent or active TB. Adopting a systematic approach that also takes into account the need for individualized variations based on the available evidence is the key to successfully integrate ART and TB treatment and improve treatment outcomes.

Lichenoid drug reaction due to anti-tubercular therapy presenting as erythroderma

First-line anti-tubercular therapy (ATT) is very effective in management of tuberculosis and is usually well tolerated. Varied spectrum of cutaneous adverse drug reactions is associated with ATT, of which lichenoid drug eruption (LDR) constitutes approximately 10% of the cases. However, LDR presenting as erythroderma is very rare. Here, we report a case of exfoliative dermatitis secondary to LDR which developed after 5 months of ATT.

Cutaneous adverse drug reactions in patients with peripheral blood eosinophilia during antituberculosis treatment

BACKGROUND/AIMS

Peripheral eosinophilia during tuberculosis (TB) treatment is common, but has not been fully evaluated. The aim of this study was to determine the prevalence and clinical significance of peripheral blood eosinophilia in patients undergoing anti-TB treatment.

METHODS

We retrospectively reviewed the clinical and laboratory data of patients who received anti-TB treatment and had peripheral blood eosinophilia (> 5% of the total white blood cell count) at the Chonnam National University Hospital between January 2010 and December 2014.

RESULTS

Of all 2,234 patients with TB who received anti-TB treatment, 397 (17.8%) had peripheral blood eosinophilia. Of the 397 with eosinophilia, we reviewed the data of 262 (66%), and cutaneous adverse drug reactions (CADRs) were observed in 161 (61.5%). Of the 161 with CADRs, itching (47.2%) and skin rash (47.8%) were common. Older age, abnormal liver function, and higher peak blood eosinophil percentage were associated with CADRs in multivariate analysis. There was a significant relationship between increased peak eosinophil counts and the degree of severity of CADRs.

CONCLUSION

Peripheral blood eosinophilia is a relatively common occurrence during anti-TB treatment. Peripheral blood eosinophil counts were higher according to the degree of severity of CADRs.

Cost of managing severe cutaneous adverse drug reactions to first-line tuberculosis therapy in South Africa

OBJECTIVE

To compare the cost of managing treatment-limiting cutaneous adverse drug reactions (CADRs) to first-line anti-tuberculosis drugs to an alternative strategy of immediate treatment initiation using second-line drugs in a South African setting.

METHODS

Clinical and cost data were retrospectively collected from patients presenting with a first-line anti-tuberculosis therapy-associated CADR. Costs (2016 US$) were estimated using an ingredient's approach from a healthcare provider perspective. The per-patient and total cost of drug rechallenge, the current management strategy for severe CADR, was calculated. Alternative strategies involving second-line treatment were derived from literature and expert clinical advice.

RESULTS

Drug rechallenge costs US $5831 (95% CI: 5134-6527) per patient. Hospitalisation accounted for 62% of this cost. Alternative CADR management strategies using regimens containing rifabutin, bedaquiline and/or delamanid cost 44%-55% less than drug rechallenge (US $2651-US $3276/patient). In univariate sensitivity analyses, drug rechallenge and alternative strategies were most sensitive to hospitalisation and tuberculosis drug costs, respectively.

CONCLUSION

Cutaneous adverse drug reactions to anti-tuberculosis treatment represent a significant economic burden. An alternate strategy of outpatient-initiated second-line therapy is economically feasible but requires clinical validation to assess effectiveness.

Drug hypersensitivity in HIV infection

PURPOSE OF REVIEW

Immune-mediated adverse drug reactions (IM-ADRs) are many times more common in HIV-infected patients. Usual offending drugs include antiretroviral and antiinfectives, but the burden of specific drug IM-ADRs is population-specific; changing as new and fixed dose combinations enter the market, and drug-resistance patterns demand. This review considers recent literature on epidemiology, mechanisms, clinical management and prevention of IM-ADRs amongst persons living with HIV/AIDS.

RECENT FINDINGS

Epidemiological studies continue to describe high rates of delayed hypersensitivity to known offenders, as well as similar reactions in preexposure prophylaxis. IM-ADRs to oral and injectable integrase strand transfer inhibitors are reported with expanding use. The clinical spectrum and management of IM-ADRs occurring in HIV-infected populations is similar to uninfected; with exceptions such as a recently described severe delayed efavirenz DILI with high mortality. Furthermore, the context can be unique, such as the lower than expected mortality in a Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS/TEN) cohort from a HIV/TB high burden setting. Programmatic data showing the near complete elimination of Abacavir drug hypersensitivity syndrome following implementation of HLA-B57:01 screening is a stellar example of how prevention is possible with mechanistic insight.

SUMMARY

IM-ADRs remain a challenge in persons living with HIV. The complexities posed by polypharmacy, overlapping drug toxicities, drug interactions, overlap of IM-ADRs with other diseases, limited alternative drugs, and vulnerable patients with advanced immunosuppression with high mortality, necessitate increased use of drug provocation testing, treat-through and desensitization strategies. There is an urgent need for improved diagnostics and predictive biomarkers for prevention, or to guide treat-through, rechallenge and desensitization approaches.

An Update on Adverse Cutaneous Drug Reactions in HIV/AIDS

Background

The global mortality from HIV and the cutaneous burden of infective, inflammatory and malignant diseases in the setting of AIDS have significantly declined following the advent of highly active antiretroviral therapy. Regrettably, there has been a contemporaneous escalation in the incidence of adverse cutaneous drug reactions (ACDR), with studies attesting that HIV-positive individuals are a hundred times more susceptible to drug reactions than the general population, and advanced immunodeficiency portending an even greater risk. Several variables are accountable for this amplified risk in HIV.

Summary

Adverse reactions to trimethoprim-sulfamethoxazole are the most common, increasing from approximately 2–8% in the general population over to 43% amongst HIV-positive individuals to approximately 69% in subjects with AIDS. Antituberculosis drugs and antiretrovirals are also well-known instigators of ACDR. Cutaneous reactions range from mild morbilliform eruptions to severe, life-threatening manifestations in the form of Stevens-Johnson syndrome/toxic epidermal necrolysis. Histological features vary from vacuolar interface changes to full-thickness epidermal necrosis with subepidermal blister formation. A precipitous diagnosis of the ACDR, clinically and histologically if necessary, together with the isolation of the causative drug is critical. The identification process, however, is often complex and multifaceted due to polypharmacy and inconclusive data on which drugs are the most likely offending agents, especially against the background of tuberculosis co-infection.

Key Messages

Whilst milder cutaneous reactions are treated symptomatically, severe reactions mandate immediate treatment discontinuation without rechallenge. Further studies are required to establish safe rechallenge guidelines in resource-limited settings with a high HIV and tuberculosis prevalence.

Antibiotic allergy

Antibiotics are the commonest cause of life-threatening immune-mediated drug reactions that are considered off-target, including anaphylaxis, and organ-specific and severe cutaneous adverse reactions. However, many antibiotic reactions documented as allergies were unknown or not remembered by the patient, cutaneous reactions unrelated to drug hypersensitivity, drug-infection interactions, or drug intolerances. Although such reactions pose negligible risk to patients, they currently represent a global threat to public health. Antibiotic allergy labels result in displacement of first-line therapies for antibiotic prophylaxis and treatment. A penicillin allergy label, in particular, is associated with increased use of broad-spectrum and non-β-lactam antibiotics, which results in increased adverse events and antibiotic resistance. Most patients labelled as allergic to penicillins are not allergic when appropriately stratified for risk, tested, and re-challenged. Given the public health importance of penicillin allergy, this Review provides a global update on antibiotic allergy epidemiology, classification, mechanisms, and management.

Prevalence and Clinical Features of Drug Reactions With Eosinophilia and Systemic Symptoms Syndrome Caused by Antituberculosis Drugs: A Retrospective Cohort Study

Purpose

Although there have been reported cases of drug reactions with eosinophilia and systemic symptoms (DRESS) syndrome caused by antituberculosis drugs, there has been no research to examine its prevalence. This study assessed the prevalence and clinical characteristics of DRESS syndrome caused by antituberculosis drugs.

Methods

The electronic medical records of a cohort consisting of adult patients diagnosed with tuberculosis between July 2006 and June 2010 were reviewed and retrospectively inspected. We searched the surveillance system for adverse drug reactions and the electronic medical records to identify patients who reported severe cutaneous adverse reactions to antituberculosis drugs. These patients were then re-assessed using a European Registry of Severe Cutaneous Adverse Reactions to Drugs and Collection of Biological Samples (RegiSCAR) scoring system. Clinical characteristics, including the symptoms and latency of DRESS syndrome, the therapeutic dosage and period of steroids, and the final duration of tuberculosis therapy, were examined.

Results

Of the 1,253 adult patients with tuberculosis receiving antituberculosis drugs, 15 were identified as potential cases of DRESS syndrome (prevalence of 1.2%). Ethambutol was the most frequently used drug (53.5%), followed by rifampicin (26.7%), pyrazinamide (20.0%), streptomycin (13.3%), and isoniazid (6.7%). The median latency after day 1 of antituberculosis medication was 42 days. The median daily dose of steroids, expressed in prednisone-equivalent units, was 33-mg/day, and the median dosing period was 14 days. The duration of tuberculosis treatment was 76 days longer than the standard treatment period of 180 days. There was a significant difference in the peak eosinophil counts of DRESS syndrome patients according to RegiSCAR scores. Moreover, there was a significant quantitative correlation between the RegiSCAR score and peak eosinophil count. A negative correlation was also found between the RegiSCAR score and latency.

Conclusions

This study confirmed the prevalence of DRESS syndrome in a cohort of adult patients with tuberculosis.

Severe Delayed Cutaneous and Systemic Reactions to Drugs: A Global Perspective on the Science and Art of Current Practice

Most immune-mediated adverse drug reactions (IM-ADRs) involve the skin, and many have additional systemic features. Severe cutaneous adverse drug reactions (SCARs) are an uncommon, potentially life-threatening, and challenging subgroup of IM-ADRs with diverse clinical phenotypes, mechanisms, and offending drugs. T-cell-mediated immunopathology is central to these severe delayed reactions, but effector cells and cytokines differ by clinical phenotype. Strong HLA-gene associations have been elucidated for specific drug-SCAR IM-ADRs such as Stevens-Johnson syndrome/toxic epidermal necrolysis, although the mechanisms by which carriage of a specific HLA allele is necessary but not sufficient for the development of many IM-ADRs is still being defined. SCAR management is complicated by substantial short- and long-term morbidity/mortality and the potential need to treat ongoing comorbid disease with related medications. Multidisciplinary specialist teams at experienced units should care for patients. In the setting of SCAR, patient outcomes as well as preventive, diagnostic, treatment, and management approaches are often not generalizable, but rather context specific, driven by population HLA-genetics, the pharmacology and genetic risk factors of the implicated drug, severity of underlying comorbid disease necessitating ongoing treatments, and cost considerations. In this review, we update the basic and clinical science of SCAR diagnosis and management.

Difficult clinical management of antituberculosis DRESS syndrome complicated by MRSA infection: A case report

RATIONALE

Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is a severe drug-induced hypersensitivity reaction characterized by skin rash, fever, blood abnormalities, and multiple organ involvement. The diagnosis of DRESS syndrome is often delayed because of its variable presentation. Prompt withdrawal of the culprit drug is the definitive treatment. DRESS syndrome induced by antituberculosis drugs has rarely been reported.

PATIENT CONCERNS

A 50-year-old man admitted to our hospital with recurrent episodes of progressive rash, fever, eosinophilia, lymphadenopathy, hepatic, and pulmonary involvement were experienced after repeat trials of the same antituberculosis drugs.

DIAGNOSES

We diagnosed it as DRESS caused by antituberculosis drugs.

INTERVENTIONS

The case responded well to treatment with systemic corticosteroids and intravenous immunoglobulins. However, repeated bouts of infection with methicillin-resistant Staphylococcus aureus occurred during treatment (clavicular osteomyelitis and knee septic arthritis). He was cured after treatment with linezolid.

OUTCOMES

The patient was discharged on day 112. At 8-month follow-up, there was no relapse of drug eruption and joint swelling.

LESSONS

Early diagnosis and prompt withdrawal of all suspected drugs is a key tenet of the treatment of DRESS. Our case report highlights the risks inherent in delayed diagnosis of DRESS and the challenges in the clinical management of this condition. Pulmonary manifestations with radiological changes on chest X-ray and CT can be seen in DRESS. These changes need to be differentiated from those caused by pulmonary infections. Clavicular osteomyelitis infected with MRSA may be caused by iatrogenic injury during subclavian vein catheterization. This type of MRSA infections should be treated for 4 to 6 weeks. Blood eosinophilia could be a useful marker of disease progression and treatment response in patients with DRESS. However, more experience and clinical evidence is needed to confirm this.

Official American Thoracic Society/Centers for Disease Control and Prevention/Infectious Diseases Society of America Clinical Practice Guidelines: Treatment of Drug-Susceptible Tuberculosis

The American Thoracic Society, Centers for Disease Control and Prevention, and Infectious Diseases Society of America jointly sponsored the development of this guideline for the treatment of drug-susceptible tuberculosis, which is also endorsed by the European Respiratory Society and the US National Tuberculosis Controllers Association. Representatives from the American Academy of Pediatrics, the Canadian Thoracic Society, the International Union Against Tuberculosis and Lung Disease, and the World Health Organization also participated in the development of the guideline. This guideline provides recommendations on the clinical and public health management of tuberculosis in children and adults in settings in which mycobacterial cultures, molecular and phenotypic drug susceptibility tests, and radiographic studies, among other diagnostic tools, are available on a routine basis. For all recommendations, literature reviews were performed, followed by discussion by an expert committee according to the Grading of Recommendations, Assessment, Development and Evaluation methodology. Given the public health implications of prompt diagnosis and effective management of tuberculosis, empiric multidrug treatment is initiated in almost all situations in which active tuberculosis is suspected. Additional characteristics such as presence of comorbidities, severity of disease, and response to treatment influence management decisions. Specific recommendations on the use of case management strategies (including directly observed therapy), regimen and dosing selection in adults and children (daily vs intermittent), treatment of tuberculosis in the presence of HIV infection (duration of tuberculosis treatment and timing of initiation of antiretroviral therapy), as well as treatment of extrapulmonary disease (central nervous system, pericardial among other sites) are provided. The development of more potent and better-tolerated drug regimens, optimization of drug exposure for the component drugs, optimal management of tuberculosis in special populations, identification of accurate biomarkers of treatment effect, and the assessment of new strategies for implementing regimens in the field remain key priority areas for research. See the full-text online version of the document for detailed discussion of the management of tuberculosis and recommendations for practice.

Therapeutic Trial of Rifabutin After Rifampicin-Associated DRESS Syndrome in Tuberculosis-Human Immunodeficiency Virus Coinfected Patients

Elimination of a rifamycin from the treatment regimen for tuberculosis negatively impacts outcomes. Cross-reactivity between the rifamycins after drug eruptions is unclear. We report 6 consecutive human immunodeficiency virus-infected patients with rifampicin-associated drug rash with eosinophilia and systemic symptoms (DRESS) syndrome confirmed on diagnostic rechallenge. The patients subsequently tolerated rifabutin. These data inform clinical management of tuberculosis-associated drug reactions.

Integrated therapy for HIV and tuberculosis

Tuberculosis (TB) has been the most common opportunistic infection and cause of mortality among HIV-infected patients, especially in resource-limited countries. Clinical manifestations of TB vary and depend on the degree of immunodeficiency. Sputum microscopy and culture with drug-susceptibility testing are recommended as a standard method for diagnosing active TB. TB-related mortality in HIV-infected patients is high especially during the first few months of treatment. Integrated therapy of both HIV and TB is feasible and efficient to control the diseases and yield better survival. Randomized clinical trials have shown that early initiation of antiretroviral therapy (ART) improves survival of HIV-infected patients with TB. A delay in initiating ART is common among patients referred from TB to HIV separate clinics and this delay may be associated with increased mortality risk. Integration of care for both HIV and TB using a single facility and a single healthcare provider to deliver care for both diseases is a successful model. For TB treatment, HIV-infected patients should receive at least the same regimens and duration of TB treatment as HIV-uninfected patients. Currently, a 2-month initial intensive phase of isoniazid, rifampin, pyrazinamide, and ethambutol, followed by 4 months of continuation phase of isoniazid and rifampin is considered as the standard treatment of drug-susceptible TB. ART should be initiated in all HIV-infected patients with TB, irrespective of CD4 cell count. The optimal timing to initiate ART is within the first 8 weeks of starting antituberculous treatment and within the first 2 weeks for patients who have CD4 cell counts <50 cells/mm(3). Non-nucleoside reverse transcriptase inhibitor (NNRTI)-based ART remains a first-line regimen for HIV-infected patients with TB in resource-limited settings. Although a standard dose of both efavirenz and nevirapine can be used, efavirenz is preferred because of more favorable treatment outcomes. In the settings where raltegravir is accessible, doubling the dose to 800 mg twice daily is recommended. Adverse reactions to either antituberculous or antiretroviral drugs, as well as immune reconstitution inflammatory syndrome, are common in patients receiving integrated therapy. Early recognition and appropriate management of these consequences can reinforce the successful integrated therapy in HIV-infected patients with TB.

Lack of cross-toxicity between isoniazid and ethionamide in severe cutaneous adverse drug reactions: a series of 25 consecutive confirmed cases

BACKGROUND

Isoniazid and ethionamide are important first- and second-line anti-TB drugs (FLDs and SLDs), respectively. Ethionamide is a structural analogue of isoniazid and the two drugs share other similarities, including their metabolism, therapeutic targets, hepato-toxicity patterns and drug resistance. As a result, there has always been concern about possible cross-reactivity between them.

METHODS

Among 69 patients with drug rash with eosinophilia and systemic symptoms (DRESS), Stevens-Johnson syndrome (SJS) or toxic epidermal necrolysis (TEN) to FLDs, FLDs were stopped and SLDs added when the skin and laboratory parameters had settled. This was followed by sequential and additive rechallenge with FLDs. We report 25 consecutive cases that developed confirmed cutaneous adverse drug reactions (CADRs) to isoniazid or ethionamide used as FLD and SLD, respectively.

RESULTS

Sixty-nine participants who developed CADRs on FLDs were enrolled in the study. Twenty developed a rechallenge reaction to isoniazid and five reacted to ethionamide. Four of the 20 isoniazid cases were patch test positive, 3/20 were skin prick test positive and 13/20 reacted to oral rechallenge. All seven cases that were patch and skin prick test positive were associated with systemic reactions. Twenty of the 25 cases had DRESS and 5 had SJS/TEN. Twenty-three of the 25 cases with rechallenge reactions were HIV infected. Importantly, none of the cases that reacted to ethionamide during the rechallenge reacted to isoniazid and none who subsequently reacted to isoniazid reacted to ethionamide.

CONCLUSIONS

Our findings strongly suggest that the risk of cross-reactivity of isoniazid and ethionamide in DRESS syndrome and SJS/TEN is low. These findings have implications for clinical management.

Immediate-type hypersensitivity reactions due to antituberculosis drugs: a successful readministration protocol

BACKGROUND

Little is known about drug hypersensitivity reactions from antituberculosis drugs.

OBJECTIVE

To determine the frequency, risk factors, and characteristics of immediate-type hypersensitivity reactions from first-line antituberculosis drugs and to evaluate the usefulness of a readministration protocol for culprit drugs in this group of patients.

METHODS

The study population consisted of patients with tuberculosis who were hospitalized and treated in the authors' hospital in 2011. Demographics and disease and treatment characteristics of patients with immediate-type hypersensitivity from antituberculosis drugs were compared with the other patients. Culprit drugs were readministered gradually according to a defined protocol to patients with immediate-type hypersensitivity.

RESULTS

Tree hundred seventy-nine patients were included in the study. Eighteen immediate-type hypersensitivity reactions were detected in 13 patients (3.43%). The only identified risk factor was female sex (odds ratio 4.085). Isoniazid, rifampicin, pyrazinamide, and ethambutol were readministered in 11 patients and rifampicin was readministered in 2 patients, with 6- to 8-step protocols for each drug. Only in 2 patients did allergic reactions with rifampicin develop during the procedure. In these patients, after treatment and complete remission of allergic symptoms, the last tolerated dose was administered and the protocol was completed with the same adjustments.

CONCLUSION

Immediate-type allergic reactions from antituberculosis drugs are not rare and not related to disease or treatment characteristics. The protocols used in this study provide a useful and safe method for readministration of culprit drugs to patients with antituberculosis drug hypersensitivity.

Anti-tuberculosis drugs adverse reactions: a review of the Iranian literature

INTRODUCTION

Tuberculosis (TB) treatment, in particular therapy for multidrug-resistant TB (MDR-TB), is associated with toxicities and adverse drug reactions (ADRs).

AREAS COVERED

This paper reviews Iranian literature reporting ADRs which occurred during tuberculosis treatment. English language papers were sourced from PubMed, ScienceDirect, Wiley, Ovid and Proquest, with Google Scholar searched for Persian language articles. Reported ADRs, proportion of patients with ADRs, risk factors and determinants, as well as the characteristics of the studies were reviewed. 21 articles were included; about 60% of them were in English and three included patients with MDR-TB. The ratio of ADR per capita was 1.9 (in 6 studies) and 33.63% of patients developed an ADR (in 7 studies). Hepatitis (2.5 - 45.3%) was reported in nearly all of the studies. The mean time from initiation of medication to development of hepatitis ranged from 4.67 to 25.25 days (in 6 studies). Most cases of mortality were due to hepatotoxicity. Except for comorbidities and female gender, other risk factors such as HIV and length of hospitalization were only reported in one article.

EXPERT OPINION

The pattern of ADRs in Iranian articles was found to be similar to many other studies in the present review. We suggest that future studies resolve the confounding factors in this area that are mentioned in this review.

A retrospective study on sequential desensitization-rechallenge for antituberculosis drug allergy

Background

Antituberculosis (anti-TB) drug allergy often involves multiple concurrently administered drugs which subsequently need to be reinitiated as no better alternatives exist.

Objective

To describe the results of tailored sequential desensitization-rechallenge (D-R) for anti-TB drug allergy.

Methods

Consecutive patients who had undergone D-R to anti-TB drugs between 1 September 1997 and 31 January 2012 were recruited. Following resolution of the acute reaction, anti-TB drug was restarted at 1:6,000 to 1:3 of the final daily dose (FDD), with gradual single or multiple step daily dose escalation to the FDD. Subsequent drugs were sequentially added ≥3 days later when the preceding drug was tolerated. Full blood count and liver function tests were monitored prior to addition of each new drug.

Results

There were 11 patients of whom 10 were male, predominantly Chinese (8 patients). Regimens comprised at least 3 drugs: isoniazid (INH), rifampicin (RIF), ethambutol (EMB), pyrazinamide (PZA), or streptomycin. All patients had nonimmediate reactions, with cutaneous eruptions, where maculopapular exanthema (MPE) was the most common (8 patients). Drug-induced hypersensitivity syndrome (DIHS) occurred in 6 patients, and Stevens Johnson syndrome (SJS) in 2 patients. D-R to INH was successful in 7/9 patients (77.8%) and to RIF/EMB/PZA/streptomycin in all. Of the 2 patients who failed INH D-R, 1 developed fever and MPE on day 3, the other MPE on day 8. D-R with INH and RIF respectively was successful in 2 patients with SJS. Among DIHS patients, 1 failed D-R with INH (fever and MPE on day 3). There were 23/25 (92%) successful D-R among the 11 patients. All patients completed TB treatment of ≥5 months' duration with no cases of drug-resistant TB.

Conclusion

Tailored sequential TB drug D-R is successful where no better alternative therapies are available, with careful dose escalation and close monitoring, and after a careful risk-benefit assessment.

Management of patients with multidrug-resistant/extensively drug-resistant tuberculosis in Europe: a TBNET consensus statement

The emergence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) tuberculosis (TB) substantially challenges TB control, especially in the European Region of the World Health Organization, where the highest prevalence of MDR/XDR cases is reported. The current management of patients with MDR/XDR-TB is extremely complex for medical, social and public health systems. The treatment with currently available anti-TB therapies to achieve relapse-free cure is long and undermined by a high frequency of adverse drug events, suboptimal treatment adherence, high costs and low treatment success rates. Availability of optimal management for patients with MDR/XDR-TB is limited even in the European Region. In the absence of a preventive vaccine, more effective diagnostic tools and novel therapeutic interventions the control of MDR/XDR-TB will be extremely difficult. Despite recent scientific advances in MDR/XDR-TB care, decisions for the management of patients with MDR/XDR-TB and their contacts often rely on expert opinions, rather than on clinical evidence.

This document summarises the current knowledge on the prevention, diagnosis and treatment of adults and children with MDR/XDR-TB and their contacts, and provides expert consensus recommendations on questions where scientific evidence is still lacking.

TBNET consensus statement on the management of patients with MDR/XDR-TB has been released in theEur Respir Jhttp://ow.ly/uizRD

Clinical presentations of severe cutaneous drug reactions in HIV-infected Africans

Sub-Saharan Africa is the epicenter of the HIV pandemic and HIV-infected people are more susceptible to inflammatory dermatoses, infections, and drug eruptions. Many of the drugs used for HIV-associated opportunistic infections are associated with a higher incidence of drug-related toxicities and drug interactions. This article discusses the epidemiology, pharmacogenetics, and clinical features of idiosyncratic drug reactions in HIV-infected Africans. Special considerations in this population, including immune reconstitution inflammatory syndrome, multiple drug hypersensitivity syndrome, drug reactions in pregnancy, drug rechallenge in lichenoid drug eruptions, and anxiety/depression after cutaneous adverse drug reactions, are also briefly discussed.

Management of HIV-associated tuberculosis in resource-limited settings: a state-of-the-art review

The HIV-associated tuberculosis (TB) epidemic remains a huge challenge to public health in resource-limited settings. Reducing the nearly 0.5 million deaths that result each year has been identified as a key priority. Major progress has been made over the past 10 years in defining appropriate strategies and policy guidelines for early diagnosis and effective case management. Ascertainment of cases has been improved through a twofold strategy of provider-initiated HIV testing and counseling in TB patients and intensified TB case finding among those living with HIV. Outcomes of rifampicin-based TB treatment are greatly enhanced by concurrent co-trimoxazole prophylaxis and antiretroviral therapy (ART). ART reduces mortality across a spectrum of CD4 counts and randomized controlled trials have defined the optimum time to start ART. Good outcomes can be achieved when combining TB treatment with first-line ART, but use with second-line ART remains challenging due to pharmacokinetic drug interactions and cotoxicity. We review the frequency and spectrum of adverse drug reactions and immune reconstitution inflammatory syndrome (IRIS) resulting from combined treatment, and highlight the challenges of managing HIV-associated drug-resistant TB.