Spontaneous bleeding associated with the use of the protease inhibitor ritonavir in a hemophiliac patient with human immunodeficiency virus infection

Tolerabilities of antiretrovirals in paediatric HIV infection

Data on the efficacy and tolerability of antiretrovirals in children are limited as, in contrast to adult studies, large paediatric cohort studies are lacking. Thus, data pertaining to adults are often extrapolated to children despite the acknowledgement that children are not little adults. This review summarises information gathered from existing reports and focuses on the tolerabilities of antiretrovirals in children infected with HIV-1. The efficacy of antiretrovirals is not included in the scope of the discussion. Taste of antiretrovirals should be an important factor when considering the tolerability of antiretrovirals in children. However, antiretroviral options are often limited in young children as only some of the antiretrovirals are available as paediatric formulations. All antiretrovirals have been associated with toxicities in children, but in general, they are relatively well tolerated. The gastrointestinal system including hepatic system is most prone to being affected by these drugs. Skin rashes and hypersensitivity reactions are also associated with antiretroviral use, particularly with the non-nucleoside reverse transcriptase inhibitors. Mitochondrial toxicities that lead to impairment of liver function, pancreatic function and lactic acidosis are associated with most of the nucleoside analogues. Haematological toxicity is often a dose limiting adverse effect especially of the nucleoside analogues, in particular zidovudine. The protease inhibitors are associated with gastrointestinal intolerance (diarrhoea) and metabolic derangements that can lead to hypercholesterolaemia and hypertriglyceridaemia, which in turn and can lead to changes in body habitus. The renal system is also affected by several drugs, the most important of which is indinavir, which has been associated with renal stones and damage to the renal tubules. Fortunately, with lower incidence of major toxicity and with the range of drugs now available for paediatric use, toxicities are usually not a barrier to effect antiretroviral therapy in children.

The role of protease inhibitor therapy in children with HIV infection

In comparison with HIV infection in adults, higher HIV RNA levels in children with perinatal HIV infection, differences in the natural history of HIV disease progression, and the presence of a relatively immature immune system contribute to the more complex and problematic nature of pediatric antiretroviral therapy. Current US treatment guidelines for pediatric HIV infection advocate aggressive therapy with potent combination antiretroviral regimens, to achieve profound and durable suppression of viral replication and preservation of immune function. The combination of a protease inhibitor (PI) and dual nucleoside reverse transcriptase inhibitors (NRTIs) is the most commonly recommended form of highly active antiretroviral treatment (HAART). However, use of PI therapy in pediatrics has been constrained by the lack of suitable drug formulations, a paucity of pharmacokinetic and safety data, and drug intolerance. Pharmacokinetic studies of PIs demonstrate frequent differences between children and adults, and greater variability among children, which has led to subtherapeutic dosage regimens and the development of viral resistance. The optimal dosage of many PIs in younger children is not yet known. A therapeutically important drug interaction associated with PIs is that occurring between the various PIs themselves, which allows lower doses of PI at less frequent intervals. Dual PI regimens will probably become more common, as they permit a simpler antiretroviral regimen, lower pill/medication burden, fewer adverse effects and improved adherence. Poor adherence to antiretroviral therapy remains the greatest barrier to overall success in the treatment of HIV-infected children. The key to improving adherence in HIV-infected children is to find treatment regimens that are better suited to their normal life. With improvements in existing PIs and the development of newer ones, simplification of current antiretroviral therapy to once-daily regimens without loss of potency should be achievable. PI-containing HAART has transformed HIV infection into a chronic illness, and HIV-infected children now live longer.

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.

Possible linkage of amprenavir with intracranial bleeding in an HIV-infected hemophiliac

The use of protease Inhibitors (PI) has been associated with many adverse effects including increased tendency to bleed, which is particularly problematic in individuals with congenital coagulation disorders. We report the occurrence of spontaneous intracranial bleeding in an human immunodeficiency virus (HIV)-infected adolescent with hemophilia A who was receiving amprenavir (APV). The bleeding resolved on discontinuation of APV. This case report highlights a need for awareness of increased bleeding as a potentially serious complication associated with the use of all currently licensed PIs in individuals with hemophilia.

Acute hepatitis and bleeding possibly induced by zidovudine and ritonavir in an infant with HIV infection

Acute hepatitis led to abnormal coagulopathy, bleeding, and death in a nonhemophiliac infant infected with the human immunodeficiency virus, possibly due to zidovudine or ritonavir or both. Acute hepatitis during ritonavir treatment and episodes of spontaneous bleeding have been reported in patients with hemophilia. Zidovudine is associated with elevated liver enzymes, elevated bilirubin, and hepatomegaly leading to abnormal coagulopathy, bleeding, and death in adults. A temporal relationship between the start of combination antiretroviral therapy and onset of hepatosplenomegaly and rise in liver enzymes suggests that zidovudine or ritonavir, or both, are the likely cause of this adverse event. Ritonavir is believed to cause direct hepatotoxicity, probably by inducing acute mitochondrial toxicity, and may hasten reverse transcriptase inhibitor-induced liver toxicity. Liver function of patients receiving a combination of nucleoside reverse transcriptase inhibitor and protease inhibitors should be closely monitored.