Adverse effects of drugs used in the management of opportunistic infections associated with HIV infection

Safety and efficacy of reduced-dose pentamidine as second-line treatment for HIV-related pneumocystis pneumonia

OBJECTIVES

Parenteral pentamidine isethionate (PM) 4 mg/kg/day is recommended as an alternative therapeutic regimen after failure of first-line treatment for pneumocystis pneumonia (PCP). However, the dose is often reduced to 3 mg/kg/day in clinical settings because of high rates of adverse events and drug toxicity. Although considered equally efficacious, this lower dose has not been well evaluated.

METHODS

This was a single-center, retrospective cohort study that analyzed 75 patients with HIV-PCP who were treated with trimethoprim-sulfamethoxazole, but discontinued treatment because of treatment failure or adverse events; they were then administered 3 mg/kg/day of intravenous PM as a salvage therapy. The primary outcomes were the regimen completion rate with the reduced PM dose.

RESULTS AND CONCLUSIONS

In total, 40 (53.3%) of the eligible patients completed PCP therapy with reduced-dose PM salvage treatment. The overall survival rate of PCP was 73 (97.3%). The median duration of second-line PM treatment was 8.0 days (interquartile range: 6.0-10.0). Although, the adverse events with reduced-dose PM were observed in 41 (54.7%), including 35 treatment-limiting adverse events, grade 3 or 4 adverse events occurred in only three patients (thrombocytopenia, one patient; neutropenia, two patients). Life-threating adverse events, such as hypoglycemia and arrhythmia, were not observed with reduced-dose PM. Salvage therapy with reduced-dose PM for patients with HIV-PCP is relatively safe and effective; moreover, life-threating adverse events did not occur. This therapy could be recommended for patients with HIV-PCP who fail to respond to first-line treatment with trimethoprim-sulfamethoxazole.

Anidulafungin as an alternative treatment for Pneumocystis jirovecii pneumonia in patients who cannot tolerate trimethoprim/sulfamethoxazole

Evidence supporting the use of an echinocandin alone as an alternative agent for the treatment of Pneumocystis jirovecii pneumonia (PCP) is limited and controversial. This retrospective cohort study was conducted at National Taiwan University Hospital from 1 July 2015 to 31 December 2017. Using multivariable Cox regression analyses, the outcomes of patients receiving trimethoprim/sulfamethoxazole (TMP-SMZ) or anidulafungin single therapy as an alternative treatment for PCP were investigated. A total of 207 patients with PCP were screened and 170 patients were included in the final analysis, among whom 134 (78.8%) received TMP-SMZ and 36 (21.2%) received anidulafungin as alternative anti-PCP treatment. Overall 60-day mortality was 34.1% (58/170), and 60-day mortality did not differ significantly between the anidulafungin group (38.9%; 14/36) and the TMP-SMZ group (32.8%; 44/134) (P = 0.554). Age ≥60 years [hazard ratio (HR) = 1.840, 95% confidence interval (CI) 1.039-3.259; P = 0.036] and HIV infection (HR = 0.102, 95% CI 0.013-0.771; P = 0.027) independently predicted 60-day mortality. Patients with lower SpO₂/FiO₂ ratio (HR = 0.994, 95% CI 0.990-0.998; P = 0.005) showed a higher 60-day mortality. In the Kaplan-Meier survival analysis, anidulafungin as alternative anti-PCP treatment was not correlated with higher mortality (P = 0.605). Using TMP-SMZ or anidulafungin as alternative anti-PCP treatment had similar 60-day mortality. These findings suggest that anidulafungin therapy may be an effective and alternative treatment for PCP in patients who cannot tolerate TMP-SMZ.

Critical Review: What Dose of Rifabutin Is Recommended With Antiretroviral Therapy?

Since the advent of combination antiretroviral therapy to successfully treat HIV infection, drug-drug interactions (DDIs) have become a significant problem as many antiretrovirals (ARVs) are metabolized in the liver. Antituberculous therapy traditionally includes rifamycins, particularly rifampicin. Rifabutin (RBT) has shown similar efficacy as rifampicin but induces CYP3A4 to a lesser degree and is less likely to have DDIs with ARVs. We identified 14 DDI pharmacokinetic studies on HIV monoinfected and HIV-tuberculosis coinfected individuals, and the remaining studies were healthy volunteer studies. Although RBT may be coadministered with most nonnucleoside reverse transcriptase inhibitors, identifying the optimal dose with ritonavir-boosted or cobicistat-boosted protease inhibitors is challenging because of concern about adverse effects with increased RBT exposure. Limited healthy volunteer studies on other ARV drug classes and RBT suggest that dose modification may be unnecessary. The paucity of data assessing clinical tuberculosis endpoints concurrently with RBT and ARV pharmacokinetics limits evidence-based recommendations on the optimal dose of RBT within available ARV drug classes.

Stealth anti-CD4 conjugated immunoliposomes with dual antiretroviral drugs--modern Trojan horses to combat HIV

Highly active antiretroviral therapy (HAART) is the currently employed therapeutic intervention against AIDS where a drug combination is used to reduce the viral load. The present work envisages the development of a stealth anti-CD4 conjugated immunoliposomes containing two anti-retroviral drugs (nevirapine and saquinavir) that can selectively home into HIV infected cells through the CD4 receptor. The nanocarrier was characterized using transmission electron microscopy, FTIR, differential scanning calorimetry, particle size and zeta potential. The cell uptake was also evaluated qualitatively using confocal microscopy and quantitatively by flow cytometry. The drug to lipid composition was optimized for maximum encapsulation of the two drugs. Both drugs were found to localize in different regions of the liposome. The release of the reverse transcriptase inhibitor was dominant during the early phases of the release while in the later phases, the protease inhibitor is the major constituent released. The drugs delivered via anti-CD4 conjugated immunoliposomes inhibited viral proliferation at a significantly lower concentration as compared to free drugs. In vitro studies of nevirapine to saquinavir combination at a ratio of 6.2:5 and a concentration as low as 5 ng/mL efficiently blocked viral proliferation suggesting that co-delivery of anti-retroviral drugs holds a greater promise for efficient management of HIV-1 infection.

Optimal timing for antiretroviral therapy initiation in patients with HIV infection and concurrent cryptococcal meningitis

BACKGROUND

Currently, initiation of antiretroviral therapy (ART) in most patients with human immunodeficiency virus (HIV) infection is based on the CD4-positive-t-lymphocyte count. However, the point during the course of HIV infection at which ART should be initiated in patients with concurrent cryptococcal meningitis remains unclear. The aim of this systematic review was to summarise the evidence on the optimal timing of ART initiation in patients with cryptococcal meningitis for use in clinical practice and guideline development.

OBJECTIVES

To compare the clinical and immunologic outcomes for early initiation ART (less than four weeks after starting antifungal treatment) versus later initiation of HAART (four weeks or more after starting antifungal treatment) in HIV-positive patients with concurrent cryptococcal meningitis.

SEARCH METHODS

We searched the following databases from January 1980 to February 2011: PubMed, EMBASE, and WHO International Clinical Trials Registry Platform, AEGIS database for conference abstracts, the Cochrane Central Register of Controlled Trials, and the Cochrane Database of Systematic Reviews. A total of 35 full text articles were identified and supplemented by a bibliographic search. We contacted researchers and relevant organizations and checked reference lists of all included studies.

SELECTION CRITERIA

Randomized controlled trials that compared the effect of ART (consisting of three drug combinations) initiated early or delayed in HIV patients with cryptococcal meningitis.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study eligibility, extracted data, and graded methodological quality. Data extraction and methodological quality were checked by a third author who resolved differences when these arose. Where clinically meaningful, we performed a meta-analysis of dichotomous outcomes using the relative risk (RR) and report the 95% confidence intervals (95% CIs).

MAIN RESULTS

Two eligible randomized controlled trials were included (N = 89). In our pooled analysis, we combined the clinical data for both trials comparing early initiation ART versus delayed initiation of ART. There was no statistically significant difference in mortality (RR=1.40, 95% CI [0.42, 4.68]) in the group with early initiation of ART compared to the group with delayed initiation of ART.

AUTHORS' CONCLUSIONS

This systematic review shows that there is insufficient evidence in support of either early or late initiation of ART. For the moment, because of the high risk of immune reconstitution syndrome in patients with cryptococcal meningitis, we recommend that ART initiation should be delayed until there is evidence of a sustained clinical response to antifungal therapy. However, large studies with appropriate comparison groups, and adequate follow-up are warranted to provide the evidence base for effective decision making.

A prospective study of antituberculous drug-induced hepatotoxicity in an area endemic for liver diseases

Purpose

Identification of risk factors associated with antituberculosis drug-induced hepatotoxicity (anti-TB-DIH) is important, especially in endemic area for TB and liver disease. This study assessed the incidence and risk factors of anti-TB-DIH in upper Egyptian patients treated for active pulmonary and extra-pulmonary TB.

Methods

A total of 100 consecutive TB patients were prospectively followed up both clinically and biochemically before and during their course of anti-TB therapy with daily doses of isoniazid, rifampin, ethambutol, and pyrazinamide, or streptomycin.

Results

Anti-TB-DIH developed in 15 (15%) patients within 15–60 days (median: 30 days) from the onset of therapy. Liver function normalized in 10 (60%) patients within 2 weeks from cessation of therapy. No recurrence of DIH was observed after reintroduction of therapy. Only 1 patient died from fulminant hepatic failure despite discontinuation of all anti-TB drugs. By univariate analysis, patients with anti-TB-DIH had more pre-existing liver disease (P = 0.024; OR: 3.60; 95% CI: 1.16–11.18), lower body mass index (BMI; P = 0.037; OR: 3.73; 95% CI: 1.04–10.56), lower serum albumin (P = 0.035; OR: 3.31; 95% CI: 1.04–10.56), and more extensive disease (P = 0.033; OR: 3.50; 95% CI: 1.11–11). Age, gender, raised baseline transaminases level, inclusion of pyrazinamide, and inactive hepatitis B or C carrier state were not significant risk factors of DIH. Using multivariate regression analysis, only pre-existing liver disease and lower BMI of 20 kg/m² or less were independent predictors of DIH (P = 0.024 and P = 0.047, respectively).

Conclusion

Anti-TB-DIH is not uncommon, needs early recognition and treatment, and is more in patients with pre-existing liver disease and low BMI.

HIV-1 infection and the kidney: an evolving challenge in HIV medicine

With the advent of highly active antiretroviral therapy (HAART), the incidence of opportunistic infections has declined substantially, and cardiovascular, liver, and renal diseases have emerged as major causes of morbidity and mortality in individuals with human immunodeficiency virus (HIV). Acute renal failure is common in HIV-infected patients and is associated with acute infection and medication-related nephrotoxicity. HIV-associated nephropathy is the most common cause of chronic kidney disease in HIV-positive African American populations and may respond to HAART. Other important HIV-associated renal diseases include HIV immune complex kidney diseases and thrombotic microangiopathy. The increasing importance of non-HIV-associated diseases, such as diabetes mellitus, hypertension, and vascular disease, to the burden of chronic kidney disease has been recognized, focusing attention on prevention and control of these diseases in HIV-positive individuals. HIV-positive individuals who experience progression to end-stage renal disease and who have undetectable HIV-1 viral loads while receiving HAART should be evaluated for renal transplant. Emerging evidence suggests that HIV-positive individuals may have graft and patient survival comparable to HIV-negative individuals. Several studies suggest that HIV-1 can potentially infect renal cells, and HIV transgenic mice have clarified the roles of a number of HIV proteins in the pathogenesis of HIV-associated renal disease. Host factors may modify disease expression at the level of cytokine networks and the renal microvasculature and contribute to the pathogenic effects of HIV-1 infection on the kidney.

Progression of Pneumocystis jiroveci Pneumonia in Patients Receiving Echinocandin Therapy

Echinocandins are a novel class of antifungal drugs that target beta (1, 3)-D-glucan synthesis. Animal studies have shown that these agents have activity against Pneumocystis jiroveci infection; however, clinical data are lacking. We reviewed all cases of proven P. jiroveci pneumonia (PCP) in non-human immunodeficiency virus-infected patients at our hospital over a 5 year period (2001-2005). Two patients received conventional PCP treatment and concomitant use of echinocandins for presumed invasive aspergillus. In both cases, PCP progressed, and the patient died. The use of echinocandins in the prevention or treatment of PCP cannot be recommended without evidence to support their effectiveness.

An update on current practices in the management of ocular toxoplasmosis

PURPOSE

To update information that was published by the AMERICAN JOURNAL OF OPHTHALMOLOGY in 1991 about treatment practices for ocular toxoplasmosis by uveitis specialists.

DESIGN

Physician survey.

METHODS

A written questionnaire was distributed to all physician-members (n = 147) of the American Uveitis Society. The questionnaire was modeled after a similar device used to survey uveitis specialists in 1991. Information contained on 96 returned questionnaires was tabulated.

RESULTS

Among 79 respondents who evaluate and manage patients with ocular toxoplasmosis, 15% treat all cases regardless of clinical findings (in contrast to 6% in 1991). The major indications for treatment among other respondents were severe inflammatory responses and proximity of retinal lesions to the fovea and optic disk. The majority of clinical factors considered in five categories (vision, lesion location, lesion size, lesion characteristics, and vitreous inflammatory reaction) were identified to be relative or absolute indications for treatment by a greater proportion of respondents in the current survey than in the 1991 survey. A total of nine drugs (or commercially available combinations) were used in 24 different regimens as treatments of choice for typical cases of recurrent toxoplasmic retinochoroiditis, with the combination of pyrimethamine, sulfadiazine, and prednisone being the most commonly used regimen (29% of respondents).

CONCLUSIONS

Uveitis specialists appear to be more likely to treat patients with ocular toxoplasmosis in 2001 than in 1991. Although the majority of survey respondents adhere to a traditional approach to the management of toxoplasmic retinochoroiditis (a discrete course of systemic drug treatment during active disease using multiple antiparasitic drugs with or without corticosteroids), there is still no consensus regarding the choice of antiparasitic agents for treatment regimens. Survey results provide useful information for treating physicians and for clinical investigators interested in therapy.

Antituberculosis drug-induced hepatotoxicity. The role of hepatitis C virus and the human immunodeficiency virus

Until recently it was thought that age greater than 35 yr was the main risk factor for the development of drug-induced hepatitis (DIH) in patients receiving antituberculosis therapy. We conducted a study to determine whether infection with either the hepatitis C virus or the human immunodeficiency virus (HIV) were significant risk factors for the development of DIH in patients receiving antituberculosis therapy. Our study consisted of two parts. In the first part, 134 consecutive patients admitted for the treatment of tuberculosis (TB) were followed for the development of DIH. All of these patients were also screened for the presence of hepatitis C and HIV. In the second part of the study, those patients who were hepatitis C positive and who developed DIH on repeated reintroduction of the anti-TB drugs were offered a liver biopsy. If active inflammation, which may be suggestive of hepatitis C infection, was present on the biopsy specimen, treatment with alpha-interferon was begun and the anti-TB drugs were subsequently reintroduced. During the 18 mo of the study, 22 patients developed DIH. The relative risk of developing DIH if the patient was hepatitis C or HIV positive was fivefold and fourfold, respectively (p < 0.05). If a patient was coinfected with both hepatitis C and HIV the relative risk of developing DIH was increased 14.4-fold (p < 0.002). In the treatment part, four patients were treated with alpha-interferon, and all were able to undergo the reintroduction of anti-TB therapy without reoccurrence of DIH. Infection with hepatitis C and HIV are independent and additive risk factors for the development of DIH during TB therapy. The treatment of hepatitis C with alpha-interferon may allow the reintroduction of anti-TB agents in those who previously developed DIH when exposed to these drugs.

Drug-induced uveitis

Uveitis has been reported in association with a variety of topical, intraocular, periocular, and systemic medications. To establish causality of adverse events by drugs, in 1981, Naranjo and associates proposed seven criteria, which are related to the frequency and documentation of the event; circumstances of occurrence, recovery, and recurrence; and coexistence of other factors or medications. Rarely does a drug meet all seven criteria. The authors review reports of drug-associated uveitis, applying the seven criteria and examining possible mechanisms. Only systemically administered biphosphonates and, perhaps, topical metipranolol meet all seven criteria. Systemic sulfonamides, rifabutin, and topical glucocorticoids fulfill at least five criteria.

Population pharmacokinetics of atovaquone in patients with acute malaria caused by Plasmodium falciparum

The population pharmacokinetics of atovaquone were examined in 458 black, Oriental, and Malay patients with acute Plasmodium falciparum malaria receiving atovaquone alone or concomitantly with other drugs. Oral clearance (CL/F) showed a 0.674 power relationship with weight and is similar in Oriental and Malay subjects but 58.5% lower in black subjects. On the basis of mean body weight, the population estimate of CL/F is 3.28, 8.49, and 9.13 L/hr in black, Oriental, and Malay subjects, respectively. The relationship between apparent volume of distribution (V area/F) and weight was linear and similar in all three races at 7.98 L/kg. The population estimate of V area/F is 345, 383, and 428 L in black, Oriental, and Malay subjects, respectively. The bioavailability of the high and low doses of atovaquone was similar. Neither CL/F nor V area/F were significantly affected by age, gender, and the coadministration with chloroguanide (proguanil), pyrimethamine, and tetracycline. Half-life (t1/2) showed a 0.326 power relationship with weight; thus, the population estimate of t1/2 in black, Oriental, and Malay subjects is 72.9, 31.3, and 32.5 hours, respectively. The final magnitudes of interpatient variability in CL/F and V area/F were 68% and 49%, respectively.

Antibacterial-induced hepatotoxicity. Incidence, prevention and management

Hepatotoxic reactions to antibacterials are rare, occurring with an estimated frequency of between 1 and 10 per 100,000 drug prescriptions for most antibacterials. Although many antibacterial-induced hepatotoxic reactions have a characteristic clinical and biochemical pattern e.g. cholestatic hepatitis (flucloxacillin) or fatty liver (tetracycline), many can also present with a variety of clinicopathological patterns e.g. nitrofurantoin is associated with the development of acute hepatitis, granulomatous hepatitis and chronic active hepatitis. Almost all reactions are idiosyncratic, with no diagnostic laboratory tests to aid the diagnosis. Early diagnosis is essential and requires a vigilant physician to elicit a detailed drug history. Although the outcome is usually good when the offending antibacterial is withdrawn, morbidity may persist for years and fatalities have occurred, particularly when there is a delay in recognising the hepatotoxic antibacterial. There is no specific treatment for antibacterial-induced hepatotoxicity other than withdrawing the implicated drug. For severe disease, however, liver transplantation should be considered.