Hypersensitivity reactions during antiretroviral regimens with protease inhibitors

Cutaneous toxicities of antiretroviral therapy for HIV: part I. Lipodystrophy syndrome, nucleoside reverse transcriptase inhibitors, and protease inhibitors

Antiretroviral medications for the treatment of HIV are common drugs with diverse and frequent skin manifestations. Multiple new cutaneous effects have been recognized in the past decade. Dermatologists play an important role in accurately diagnosing and managing the cutaneous toxicities of these medications, thereby ensuring that a patient has as many therapeutic options as possible for life-long viral suppression. Part I of this two-part series on the cutaneous adverse effects of antiretroviral medications will discuss HIV-associated lipodystrophy syndrome, which can be seen as a result of many antiretroviral medications for HIV, and the specific cutaneous effects of the nucleoside reverse transcriptase inhibitors and protease inhibitors.

Metabolic and hepatobiliary side effects of antiretroviral therapy (ART)

Although antiretroviral therapy (ART) for human immunodeficiency virus (HIV) has been in use since 1987, the initiation of highly active ART has produced an increase in adverse drug reactions. This is a new challenge as many of the adverse drug reactions attributable to ART may be indistinguishable from non-drug-related illnesses. The emergency physician must be aware of the potential complications of ART as affected patients may present with nonspecific symptoms. The focus of this article is the metabolic and hepatobiliary adverse effects of ART.

Adverse cutaneous reactions to antimicrobials in patients with human immunodeficiency virus infection

Adverse reactions to medication are significant contributors to morbidity and mortality in patients with human immunodeficiency virus (HIV) infection. Cutaneous events not only constitute a significant portion of these reactions, they may also herald developing systemic reactions such as hemato-, nephro-, and hepatotoxicity. The identification of cutaneous adverse reactions and drug culprits and the proper management of reactions are of paramount importance for these patients. This review focuses specifically on adverse cutaneous reactions to antimicrobials that are commonly used in the management of patients with HIV infection.

Reacciones de hipersensibilidad a antirretrovirales en pacientes con infección por el virus de la inmunodeficiencia humana

Drug hypersensitivity reactions in the HIV-positive patient are a major problem in management of these patients and, nowadays the antiretroviral agents are the main cause of those reactions, exceeding cotrimoxazole. The present review focuses on immunologic reactions that have been reported associated with antiretroviral agents. We have reviewed case reports on Medline(R) to September 2005. Evidence that these reactions are immune mediated is largely based on the typical symptomatology and few studies have been done to determine the pathogenesis mechanisms. The clinical management of this type of reactions is complex because of differential diagnosis and of potential severity. It is essential that research is now carried out into the pathogenic mechanisms and so, we shall be able to offer an efficacious protocol to manage these situations.

Amprenavir-induced maculopapular exanthem followed by desensitization in a patient with late-stage human immunodeficiency virus

BACKGROUND

Amprenavir, a human immunodeficiency virus type 1 (HIV-1) protease inhibitor, is approved for the treatment of HIV infection in combination with other antiretroviral agents in treatment-naive and experienced patients. Amprenavir is generally well tolerated. However, cutaneous hypersensitivity reactions to amprenavir occur in up to 28% of patients, with treatment discontinuation required in 3% of cases.

OBJECTIVE

To report successful desensitization to amprenavir after the occurrence of a maculopapular exanthem in an HIV-infected patient with late-stage disease and limited antiretroviral treatment options.

METHODS

Incremental doses of 0.025, 0.1, 0.25, 1, 2.5, 7.5, 25, 50, 100, 300, 600, and 1,200 mg of amprenavir oral solution were administered via percutaneous endoscopic gastrostomy tube at 20- to 30-minute intervals.

RESULTS

The patient successfully tolerated amprenavir desensitization and has continued therapy without recurrence of rash at 19 months of follow-up.

CONCLUSION

Desensitization may permit the continued use of amprenavir in HIV-positive patients with a history of amprenavir-induced maculopapular eruptions who have limited alternate treatment options.

Cutaneous manifestations of antiretroviral therapy

The pandemic created by HIV, a retrovirus, has stimulated increased research in viral diseases and has generated greater interest in the development of antiretroviral medications. These new medications are presently divided into 3 categories: protease inhibitors (PIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs), and nucleoside reverse transcriptase inhibitors (NRTIs). These antiretroviral agents carry their own risk for causing adverse reactions, as well as drug interactions. The most recently approved class of antiretrovirals, PIs have been associated with lipodystrophy syndrome, hypersensitivity reactions, urticaria, morbilliform eruptions, and a large number of drug interactions. NNRTIs have resulted in various cutaneous eruptions, as well as a hypersensitivity syndrome. NRTIs have resulted in alterations of the nails, nail and mucocutaneous pigmentation, hair changes, vasculitis, and morbilliform eruptions. This article focuses on the cutaneous manifestations of antiretroviral therapy to help dermatologists recognize them.

Hypersensitivity reactions during therapy with the nucleoside reverse transcriptase inhibitor abacavir

BACKGROUND

Hypersensitivity reactions consist of a variable group of clinical findings and have been described for a wide variety of chemical compounds.

OBJECTIVE

This review characterizes the clinical profile of hypersensitivity to the nucleoside reverse transcriptase inhibitor abacavir sulfate.

METHODS

We performed a retrospective medical review of pooled adverse events data from approximately 200,000 patients who received abacavir in clinical trials, through expanded-access programs, or by prescription from 1996 through 2000. Screened cases of hypersensitivity were classified as either definitive or probable. Definitive cases were identified when initial symptoms resolved on interruption of abacavir therapy and returned on reintroduction of abacavir therapy.

RESULTS

A total of 1803 cases were identified, 1302 in the 30,595 patients participating in clinical trials or the expanded-access program and 501 in patients from the post-marketing experience. On review, 176 (9.8%) of these cases were considered definitive and the remainder probable. Based on the 1302 cases identified in clinical trials or the expanded-access program, the calculated incidence of hypersensitivity was 4.3%. Symptoms reported in > or = 20% of cases of this multiorgan reaction included fever, rash, malaise/fatigue, and gastrointestinal symptoms such as nausea, vomiting, and diarrhea, among others. Respiratory symptoms occurred in 30% of cases and included dyspnea (12%), cough (10%), and pharyngitis (6%). In 90% of cases, hypersensitivity reactions occurred within the first 6 weeks after initiation of abacavir (median time, 11 days); after an initial reaction, rechallenge with abacavir resulted in the reappearance of symptoms within hours of reexposure. Hypotension was present in 25% of these rechallenge reactions. Among patients who received abacavir in clinical trials, the mortality rate was 0.03% (3 per 10,000 patients).

CONCLUSIONS

Hypersensitivity to abacavir is an idiosyncratic reaction and a distinct clinical syndrome characterized predominantly by systemic involvement. It can be expected to appear as a treatment-limiting event in approximately 5% of patients. The appearance of clinical symptoms consistent with this syndrome mandates immediate discontinuation of abacavir. Hypersensitivity to abacavir is an absolute contraindication to subsequent treatment with any formulation that includes this agent.

Incidence of adverse reactions in HIV patients treated with protease inhibitors: a cohort study. Coordinamento Italiano Studio Allergia e Infezione da HIV (CISAI) Group

OBJECTIVE

To assess the probability that protease inhibitor (PI) therapy might be discontinued because of adverse events (AE) and to evaluate the incidence rate of adverse reactions during PI treatment.

DESIGN

A prospective cohort, multicenter study on HIV-positive patients starting treatment with at least one PI.

SETTING

Ten departments of infectious diseases in Northern Italy.

PATIENTS

A total of 1207 patients who started PI therapy in September 1997 and were consecutively observed up to April 1999.

MAIN OUTCOME MEASURES

Adverse reactions following initiation of PI therapy, and time to therapy discontinuation due to AE.

RESULTS

During the study period, 35.9% patients presented adverse reactions of any grade, whereas 9.7% presented at least one serious AE. After 12 months of treatment, the percentage of patients who had interrupted treatment was 36% of ritonavir-treated patients, 14.2% of those treated with indinavir, 13.6% of ritonavir-saquinavir hard gel capsules (HGC)-treated patients, and 8.5% and 2.1%, respectively, for those treated with nelfinavir and saquinavir HGC. Women and patients with hepatitis experienced a significantly greater number of adverse events compared with other categories. Gastrointestinal events were more frequently observed in patients treated with either ritonavir alone or in combination with saquinavir HGC, as well as in patients receiving nelfinavir, although in this group serious events were rare. Here again, neurologic, metabolic, and hepatic toxicity occurred more frequently in ritonavir and ritonavir-saquinavir HGC treated patients. Allergic reactions were more often observed in patients receiving nelfinavir. Indinavir-treated patients presented the highest incidence of renal toxicity.

CONCLUSION

Ritonavir is the drug associated with the largest number of reactions, which appear during the first few months of treatment. Saquinavir HGC and nelfinavir are the best tolerated drugs in a clinical setting.

Indinavir-associated maculopapular eruption

Indinavir-associated adverse dermatologic reactions are rare but do occur. A 39-year-old man who was positive for the human immunodeficiency virus and had no known allergy, developed an erythematous, maculopapular eruption several hours after switching to a new triple-drug regimen consisting of stavudine, didanosine, and indinavir. The eruption completely resolved 2 weeks after he discontinued the antiretroviral combination. To preserve future treatment options, the patient was sequentially rechallenged with each agent and confirmed indinavir as the cause. The patient tolerated and responded to a new combination of stavudine, didanosine, and nelfinavir. The rapid onset of the adverse reaction suggested that it might have been immunoglobulin-E mediated. No cross-sensitivity between indinavir and nelfinavir was apparent.

A risk-benefit assessment of HIV protease inhibitors

The use of triple regimens, often called highly active antiretroviral therapy (HAART), generally involving 2 nucleoside analogues and an HIV protease inhibitor, have been endorsed as the standard of care for persons with HIV initiating therapy by a number of sets of international guidelines. The widespread availability of protease inhibitor-containing regimens has been associated with a dramatic drop in the incidence of new AIDS events and mortality throughout the developed world. Use of HAART regimens, particularly in treatment-naïve individuals, is also associated with dramatic reductions in HIV RNA load, rises in CD4+ cell numbers and improvements in some aspects of immune function. However, protease inhibitor therapy is associated with a range of adverse effects, which varies between agents, and regimens frequently involve inconvenient administration schedules and disruption to patient's lives. Thus, the undoubted benefits of antiretroviral therapy come at some cost in terms of both physical and psychological morbidity to the recipient. In assessing an individual for therapy, consideration of the risk of disease events and the benefit of therapy in reducing or preventing these events must be weighed against the potential of therapy to cause morbidity. Using these criteria, we suggest that an individual with a 3 year risk of disease progression of less than 10% (based on CD4+ cell count and HIV RNA load) is more likely to a experience a morbidity if treated with HAART than if left untreated and monitored. For individuals with higher risks of HIV progression the risk versus benefit of initiating therapy may, in many cases, still be in favour of no therapy and continued observation. This will vary depending on the individuals risks (such as family and past medical history) and on the choice of agents in the regimen, some regimens having greater risks than others.

Characterization of rash with indinavir in a national patient cohort

OBJECTIVE

To characterize indinavir-associated rash using systematic data collection through postmarketing surveillance in a sample of HIV/AIDS patients.

DESIGN

HIV-infected patients identified through a medication counseling line who reported onset of a rash following initiation of indinavir therapy were included in this case series analysis. Pertinent information regarding onset, description, and management of rash; other medications initiated within two weeks of indinavir or rash onset; and medication allergy history was obtained through follow-up telephone contact. Patients were contacted weekly until the rash resolved or indinavir was discontinued.

SETTING

Stadtlanders Drug Distribution Company, located in Pittsburgh, PA.

RESULTS

Of the 110 patients identified and followed, 67% reported rash onset within two weeks of initiating indinavir therapy. The rash was initially localized in all 110 patients and subsequently spread to other areas of the body in 77% of the patients. The rash spread to the full body in 44% (49) of the patients. The rash was accompanied by pruritus in 86% of the patients, and the majority of patients (87%) were afebrile. Eighty-one patients received treatment with medications such as antihistamines or oral or topical corticosteroids. Fifty percent of patients receiving treatment for the rash reported that these medications were helpful in relieving rash symptoms. Fifty-nine percent of the patients continued indinavir therapy despite the occurrence of rash.

CONCLUSIONS

Results from this study suggest that indinavir-associated rash occurs within two weeks of initiation of therapy for the majority of patients. Typically, the rash is localized with subsequent spread and is associated with pruritus. The majority of patients are able to continue indinavir therapy despite the occurrence of rash.

Managing drug reactions to sulfonamides and other drugs in HIV infection: desensitization rather than rechallenge?

Drug reactions in patients with HIV infection, e.g. fever or rash, are a frequently occurring clinical problem. These side effects particularly are observed with sulfonamides; however, many other drugs have also shown to induce allergic reactions when given to patients with HIV infection. The production of hydroxylamines has been put forward as one of the explanations for these high incidence of reactions on drugs. Since sulfonamides are the first choice of therapy for the treatment and prophylaxis of Pneumocystis carinii pneumonia, several strategies have been developed to circumvent drug reactions. In general rechallenge or desensitization are recommended in literature. This article discusses the results and risks of rechallenge and desensitization with sulfonamides or other drugs, as mentioned in the literature. Furthermore preliminary results of rechallenge with a sulfonamide, which is not metabolized into hydroxylamines, are presented. From the data in the literature it is concluded that desensitization should be preferred to rechallenge.

Clinical aspects of Pneumocystis carinii pneumonia in HIV-infected patients: 1997

In 1997 in Europe P. carinii pneumonia is largely a disease of individuals who are either unaware of their HIV serostatus or who decline prophylaxis despite knowing they are HIV positive. Although fibre optic bronchoscopy and bronchoalveolar lavage is the diagnostic 'gold standard' polymerase chain reaction (PCR) amplification applied to oropharyngeal washings appears to have a moderate to high diagnostic yield. With further development this may provide a truly non-invasive diagnostic test. There is a clear need for an inherently more effective regimen for prophylaxis both for those with adverse reactions (ADR) to co-trimoxazole and also for those with low CD4 lymphocyte counts. Ideally, new drug regimens should afford cross-prophylaxis against bacterial, mycobacterial and other fungal infections. Given the high frequency of ADR to co-trimoxazole when used as treatment for P. carinii pneumonia, there is also a need for effective, non-toxic alternative therapies.