Seizures in human immunodeficiency virus infection

Virus-Induced Epilepsy vs. Epilepsy Patients Acquiring Viral Infection: Unravelling the Complex Relationship for Precision Treatment

The intricate relationship between viruses and epilepsy involves a bidirectional interaction. Certain viruses can induce epilepsy by infecting the brain, leading to inflammation, damage, or abnormal electrical activity. Conversely, epilepsy patients may be more susceptible to viral infections due to factors, such as compromised immune systems, anticonvulsant drugs, or surgical interventions. Neuroinflammation, a common factor in both scenarios, exhibits onset, duration, intensity, and consequence variations. It can modulate epileptogenesis, increase seizure susceptibility, and impact anticonvulsant drug pharmacokinetics, immune system function, and brain physiology. Viral infections significantly impact the clinical management of epilepsy patients, necessitating a multidisciplinary approach encompassing diagnosis, prevention, and treatment of both conditions. We delved into the dual dynamics of viruses inducing epilepsy and epilepsy patients acquiring viruses, examining the unique features of each case. For virus-induced epilepsy, we specify virus types, elucidate mechanisms of epilepsy induction, emphasize neuroinflammation's impact, and analyze its effects on anticonvulsant drug pharmacokinetics. Conversely, in epilepsy patients acquiring viruses, we detail the acquired virus, its interaction with existing epilepsy, neuroinflammation effects, and changes in anticonvulsant drug pharmacokinetics. Understanding this interplay advances precision therapies for epilepsy during viral infections, providing mechanistic insights, identifying biomarkers and therapeutic targets, and supporting optimized dosing regimens. However, further studies are crucial to validate tools, discover new biomarkers and therapeutic targets, and evaluate targeted therapy safety and efficacy in diverse epilepsy and viral infection scenarios.

Early Initiation of Antiretroviral Therapy is Protective Against Seizures in Children With HIV in Zambia: A Prospective Case-Control Study

BACKGROUND

Seizures are relatively common among children with HIV in low- and middle-income countries and are associated with significant morbidity and mortality. Early treatment with antiretroviral therapy (ART) may reduce this risk by decreasing rates of central nervous system infections and HIV encephalopathy.

METHODS

We conducted a prospective, unmatched case-control study. We enrolled children with new-onset seizure from University Teaching Hospital in Lusaka, Zambia and 2 regional hospitals in rural Zambia. Controls were children with HIV and no history of seizures. Recruitment took place from 2016 to 2019. Early treatment was defined as initiation of ART before 12 months of age, at a CD4 percentage >15% in children aged 12-60 months or a CD4 count >350 cells/mm 3 for children aged 60 months or older. Logistic regression models were used to evaluate the association between potential risk factors and seizures.

RESULTS

We identified 73 children with new-onset seizure and compared them with 254 control children with HIV but no seizures. Early treatment with ART was associated with a significant reduction in the odds of seizures [odds ratio (OR) 0.04, 95% confidence interval: 0.02 to 0.09; P < 0.001]. Having an undetectable viral load at the time of enrollment was strongly protective against seizures (OR 0.03, P < 0.001), whereas history of World Health Organization Stage 4 disease (OR 2.2, P = 0.05) or CD4 count <200 cells/mm 3 (OR 3.6, P < 0.001) increased risk of seizures.

CONCLUSIONS

Early initiation of ART and successful viral suppression would likely reduce much of the excess seizure burden in children with HIV.

Approach to Neurologic Complications in the Immunocompromised Patient

Neurologic complications are common in immunocompromised patients, including those with advanced human immunodeficiency virus, transplant recipients, and patients on immunomodulatory medications. In addition to the standard differential diagnosis, specific pathogens and other conditions unique to the immunocompromised state should be considered in the evaluation of neurologic complaints in this patient population. A thorough understanding of these considerations is critical to the inpatient neurologist in contemporary practice, as increasing numbers of patients are exposed to immunomodulatory therapies. In this review, we provide a chief complaint-based approach to the clinical presentations and diagnosis of both infectious and noninfectious complications particular to immunocompromised patients.

Seizure in HIV-infected patients: clinical presentation, cause and treatment outcome in Ethiopia-a retrospective study

BACKGROUND

The estimated number of adult patients living with HIV infection in Ethiopia in 2012 was approximately 800,000. Seizure occurs in 2 to 3% and 6.1% to 34.3% in patients with HIV infection and patients with neurological complications of HIV infection, respectively. Studies on HIV infection and seizure are rare in Ethiopia. The purpose of this study was to assess clinical presentation, cause and treatment outcome of patients with HIV infection presented with seizure.

METHODS

In this retrospective study, patients aged ≥ 13 years with HIV infection presented with seizure were included. Medical records were reviewed and demographic and clinical data were collected.

RESULTS

Records of 146 patients were analysed. Males were 55.5% and the mean age was 34 years. The diagnosis of HIV infection was made after current hospital admission in 69% of patients. Almost all patients (98.6%) had stage 4 HIV infection with very low CD4 count (mean = 77/mm³). In almost all patients seizure was a recent onset at current admission; either it started after admission (42.5%) or within 3 months prior to admission (52.5%). The types of seizures were: generalized tonic-clonic seizure [GTCS] (69.2%), focal motor with secondarily generalization [FMWSG] (19.9%) and simple focal motor (11%). The common causes of seizure were: cerebral toxoplasmosis (46%), tuberculous meningitis (35.6%) and cryptococcal meningitis (13.7%). Case-fatality was 53% and predictors of mortality were: seizure started after admission, change in mentation and comatose at initial evaluation.

CONCLUSIONS

Most patients had stage 4 HIV infection with very low CD4 count and a recent onset seizure which started within 3 months at initial evaluation. GTCS was the commonest seizure type and most causes of seizure were central nervous system opportunistic infections. The case-fatality was high and change in sensorium was an independent predictor of mortality. To prevent the high mortality and morbidity prevention of HIV infection, early diagnosis and treatment, improving diagnostic facilities and access to non-enzyme inducing antiepileptic drugs are recommended.

Current epidemiological and etiological characteristics and treatment of seizures or epilepsy in patients with HIV infection

Seizures or epilepsy is one of the common serious complications in patients with advanced human immunodeficiency virus (HIV) infection or diagnosed with immune deficiency syndrome, with higher incidence and prevalence than in the general population. Generalized seizures are the most common type in the patients. Opportunistic infections are a stereotypical predisposing factor for seizures in HIV patients, but a variety of pathogenic factors can also be found in these patients, such as metabolic perturbation and drug-drug interactions. The diagnostic criteria for seizures in these patients are the same as those in the general population. As HIV patients with seizures need to take both antivirals and antiepileptic drugs, the risk of drug-drug interactions is greatly increased, and the side effects of drugs may also become more prominent. At present, most experience in antiepileptic drug usage has come from the general population, and there is still a lack of guidance of antiepileptic drug use in special groups such as the HIV-infected people. Unlike the old-generation drugs that involve metabolisms through CYP450, the first-line antiepileptic drugs usually bypass CYP450, thus having less drug-drug interactions. In this review, we summarize the recent research progress on the above-mentioned widely discussed topics and make a prospect on future research direction.

Seizures and epilepsy secondary to viral infection in the central nervous system

Viral infection in the central nervous system (CNS) is a common cause of seizures and epilepsy. Acute symptomatic seizures can occur in the context of almost all types of acute CNS viral infection. However, late unprovoked seizures and epilepsy may not be frequent after viral infection of the CNS. The incidence of seizures and epilepsy after CNS viral infection is mainly dependent on the brain region of infection. It remains to be determined whether treatment of CNS viral infection using antiepileptic drugs (AEDs) can prevent seizures and subsequent epilepsy in patients, particularly with regard to the timing, drug choice and dosage, and duration of AEDs. The postoperative outcome of seizures in patients with intractable epilepsy caused by viral encephalitis primarily depends on the epileptogenic zone. In addition, neuroinflammation is known to be widely involved in the generation of seizures during CNS viral infection, and the effects of anti-inflammatory therapies in preventing seizures and epilepsy secondary to CNS viral infection require further studies. In this review, we discuss the incidence, mechanisms, clinical management and prognosis of seizures and epilepsy secondary to CNS viral infection, and summarize common CNS viral infections that cause seizures and epilepsy.

Association of HIV Infection with Epilepsy and Other Comorbid Conditions

Here, we aimed to investigate the associations of comorbidities in HIV patients given antiepileptic drugs. HIV patients given antiepileptic drugs for at least 6 months were considered. Comorbidities of the epileptic, HIV-positive patients were stratified according to patients' age and causes of epilepsy. Seventy-four of the 97 HIV patients identified had at least one comorbidity. Patients more than 50-years old had more comorbidities (1.9 ± 1.5 vs. 1.1 ± 1.2, p < 0.01) compared with younger subjects. The distribution of the psychiatric disorders was comparable between age-related categories. A marginally significant trend for higher frequency of psychiatric disorders was observed in patients with idiopathic epilepsy versus other causes of epilepsy (43% vs. 24%), Because the presence of comorbid disorders is a major driver for premature mortality both in HIV infection and epilepsy, strategies aimed at favoring prevention, early identification, and adequate treatment in these clinical settings should be pursued at all levels of care.

Prevalence and incidence of new-onset seizures and epilepsy in patients with human immunodeficiency virus (HIV): Systematic review and meta-analysis

BACKGROUND

The prevalence and incidence of seizures are substantially higher in patients with human immunodeficiency virus (HIV) compared with the general population and is associated with higher mortality rates. Despite this, the condition remains poorly understood, and there is variation in reported epidemiological studies. The aim of this systematic review and meta-analysis was to investigate the risk factors associated with seizures in the population with HIV, explore the source of variations, and describe management plans that can aid clinicians in the acute and long-term treatment of these patients.

METHODS

A structured electronic database search of MEDLINE, EMBASE, and Cochrane Library was conducted. Studies were included if they described clinical details of patients with HIV with seizures or epilepsy. We extracted select variables from each included study, and we estimated pooled estimates of the incidence and prevalence of seizures using random-effects meta-analysis of proportions.

RESULTS

Information on 6639 cases of patients with HIV was extracted from 9 included studies. These comprised of 2 studies from the United States of America (USA), 3 from Europe, 3 from Asia, and 1 from Africa. The pooled prevalence and incidence rate of seizures in HIV were 62 per 1000 population and 60 per 1000 population respectively. Among those who presented with new-onset seizures, 63% had seizure recurrence. At the time of first seizure, 82.3% had acquired immunodeficiency syndrome (AIDS). Factors that appeared to be linked to seizures in HIV included advanced HIV disease, opportunistic infections particularly toxoplasmosis, and metabolic derangement. Most seizures were effectively controlled by common antiepileptic drugs (AEDs).

CONCLUSIONS

The prevalence and incidence of seizures and epilepsy in the population with HIV are substantially higher than the general population. Our results suggest that advanced HIV and opportunistic infections are associated with the majority of the seizures. Early initiation of highly active antiretroviral therapy (HAART), prophylactic use of cotrimoxazole (trimethoprim-sulfamethoxazole) and routine electroencephalogram (EEG) in patients with HIV may reduce seizure incidence and frequency and help in early diagnosis of nonconvulsive seizures in this population. We recommend long-term seizure management with AED, and for patients on HAART, enzyme-inducing AED should be avoided when possible.

Neurological disorders in a consultant hospital in Northern Tanzania. A cohort study

OBJECTIVES

To determine the sociodemographic characteristics, clinical findings and outcome by HIV status in a series of adult patients presenting with neurological disorders (NDs) and admitted to a consultant hospital in Northern Tanzania.

METHODS

A cohort study took place over a 6-month period from Oct 2007 to March 2008 and included all adult patients with a neurological disorder admitted to the medical wards.

RESULTS

A total of 1790 patients were admitted during this period, of whom 337 (18.8%) were diagnosed with a neurological disorder and formed the study group. Of these 337, 69 (20.5%) were HIV-positive. Among the 69 HIV positives, 25% were previously known to be HIV seropositive of whom 82% were on antiretroviral (ARV) medication. Seropositive patients were more likely than seronegative patients to be younger, better educated, have a business occupation, present clinically with confusion, headache and aphasia and have meningitis/CNS infection or a space occupying lesion. Seropositive patients were more likely to present with a Glasgow Coma Score (GCS) of 9-12/15 (33.3% v 17.2%). Seropositive patients had a median CD4 T-lymphocyte count of 47cells/L and were more likely to be anaemic and have an elevated ESR. CT of the head was carried out on 132/337 (39%) patients. The overall findings were infarction 37%, hemorrhage 19%, tumors 15% and abscesses 9%. Brain abscess was more likely in seropositive patients and hemorrhage in seronegatives. The outcome at discharge for all patients was: death 27.6%, disability 54% and no disability 18.4% with death (39.1%) being more likely in seropositive patients. Patients presenting with coma (GCS <9/15) were more likely to die whilst those with stroke, para/quadriplegia and space occupying lesions (SOLs) were more likely to be discharged with disability. Case fatality rate was highest for tetanus 71.4%, meningitis 57.1%, cerebral malaria 42.9% and CNS infections 37.1%. Seropositive patients presenting with meningitis and other CNS infections were more likely to die than seronegatives.

CONCLUSION

This study reports NDs occurring in one fifth of adult medical admissions with stroke and infections as the leading causes. The prevalence of HIV infection in NDs was 20%. The HIV positive cohort was characterized by advanced immunosuppression, CNS infections and high mortality.

Mortality & recurrent seizure risk after new-onset seizure in HIV-positive Zambian adults

BACKGROUND

Recurrent seizure risks in HIV-positive people with new-onset seizure are largely unknown, making it challenging to offer optimal recommendations regarding antiepileptic drug (AED) initiation. Existing outcomes data is limited, and risk factor identification requires a diagnostic assessment, which is often unavailable in regions heavily effected by HIV, like sub-Saharan Africa.

METHODS

HIV-positive Zambian adults with new-onset seizure were enrolled in a prospective cohort study to determine seizure recurrence and risk factors for recurrence. Seizure etiology was evaluated, and recurrent seizures and medication usage were assessed during clinic visits. Due to unexpectedly high mortality rates, predictors of death were evaluated using proportional hazards with Gray's test to compare cumulative incidence functions for recurrent seizure across groups adjusting for the competing outcome of death.

RESULTS

95 patients were enrolled (mean age 37 years, 43% female, 83% with Karnofsky > 50) and followed for a mean of 293 days (median 241 (IQR: 29-532)). At presentation, 50 (53%) were in status epilepticus. The majority (91, 85%) had advanced HIV disease and 65 (68%) were not on combined antiretroviral therapy (cART). After extensive workup, seizure etiology remained unknown in 16 (17%). Average time to cART initiation after enrollment was 61 days. During follow up, 37 (39%) died and 23 (24%) had recurrent seizure. Most deaths (25/37, 68%) occurred in the first 60 days post-index seizure. Individuals with advanced HIV were more likely to die (HR: 19.1 [95% CI: 1.1-333.4]) as were those whose seizure etiology remained unknown (HR: 2.2 [95% CI: 1.1-4.4]). Among participants that survived from enrolment to the end of data collection on 10 May 2013 (n = 58), 20 (34%) experienced recurrent seizures.

CONCLUSIONS

New-onset seizure among HIV-positive Zambian adults is associated with high mortality despite good functional status prior to presentation. Advanced HIV infection and failure to identify an underlying seizure etiology are associated with greater mortality. Recurrent seizures occur in over a third of survivors within only 2 years of follow-up. This provides evidence to support AED initiation after first seizure in HIV-positive individuals with advanced HIV disease at the time of presentation though the risks of AED-cART interactions remain a concern and warrant further study.

Pharmacokinetic Considerations with the Use of Antiepileptic Drugs in Patients with HIV and Organ Transplants

PURPOSE OF REVIEW

Antiepileptic drugs are frequently administered to patients with HIV infection or in recipients of organ transplants. The potentially serious drug-drug interactions between the "classic" antiepileptic drugs, antiretrovirals, and immunosuppressants have been extensively studied. Evidence-based information on the second and third generation of antiepileptic drugs is almost non-existent. The purpose of this review is to analyze the pharmacokinetic profile of these newer agents to assess their potential for drug interactions with antiretrovirals and immunosuppressants.

RECENT FINDINGS

As a group, the newer generations of antiepileptic drugs have shown a more favorable drug interaction potential compared to the "classic" ones. A group of moderate enzyme-inducing drugs includes eslicarbazepine acetate, oxcarbazepine, rufinamide, and topiramate. These drugs are not as potent inducers as the "classic" drugs but may potentially decrease the serum concentrations of some antiretrovirals and immunosuppressants. Antiepileptic drugs with no or minimal enzyme-inducing properties include brivaracetam, gabapentin, lacosamide, lamotrigine, levetiracetam, perampanel, pregabalin, and vigabatrin. The newer generations of antiepileptic drugs have expanded the therapeutic options in patients with HIV infection or organ transplants.

Neurologic sequelae of primary HIV infection

Primary human immunodeficiency virus type 1 (HIV-1) infection is defined as the period from initial infection with HIV to complete seroconversion. Neurologic sequelae of primary HIV-1 infection are not uncommon, potentially affecting all parts of the nervous system. It is important for the neurologist to be aware of symptomatic primary HIV infection, as it may afford an early and accurate diagnosis of HIV infection and the opportunity for consideration of early antiretroviral therapy. This chapter introduces the clinical manifestations of primary HIV infection, including the laboratory and diagnostic approach, before detailing the various neurologic sequelae. Finally the treatment of primary HIV infection and neurologic sequelae are discussed, in the context of recent advances in the field of HIV reservoirs and longer-term neurologic complications.

Patient-Reported Adverse Effects Associated with Combination Antiretroviral Therapy and Coadministered Enzyme-Inducing Antiepileptic Drugs

AbstractConcurrent treatment with combination antiretroviral therapy (cART) and an enzyme-inducing antiepileptic drug (EI-AED) is common in resource-limited settings; however, the incidence and impact of adverse effects in cotreated patients is largely unknown. Symptoms of adverse effects were assessed by both spontaneous report and checklist for 145 human immunodeficiency virus (HIV)-infected Zambian adults initiating various treatment combinations, such as cART with an EI-AED (N = 20), cART only (N = 43), or neither drug (untreated; N = 82). At study baseline, the cART + EI-AED group reported more headache, generalized fatigue, problems with concentration, and depression than the untreated group (P < 0.01 for all). At 2 weeks, a greater proportion of cART + EI-AED participants reported increased nausea or vomiting compared with baseline (P < 0.05). Adverse effects did not appear to impact self-reported adherence at 2 weeks as 100% cART adherence was reported in 19 of 20 (95%) and 42 of 43 (98%) cART + EI-AED and cART-only participants, respectively; 100% EI-AED adherence was reported in 19 of 20 (95%) participants. However, adherence at 6 months was suboptimal in both groups with 18 of 33 (56%) participants on cART experiencing greater than 1-week lapse in pharmacy-reported medication supply. Our results highlight the need to educate patients about the increased potential for nausea and vomiting with cART + EI-AED cotreatment. Although adherence was high early during treatment, adherence should be reinforced overtime to minimize the potential for HIV and/or epilepsy treatment failure.

HIV-1-associated neurocognitive disorder: epidemiology, pathogenesis, diagnosis, and treatment

The modern antiretroviral treatment of human immunodeficiency virus (HIV-1) infection has considerably lowered the incidence of opportunistic infections. With the exception of the most severe dementia manifestations, the incidence and prevalence of HIV-associated neurocognitive disorders (HAND) have not decreased, and HAND continues to be relevant in daily clinical practice. Now, HAND occurs in earlier stages of HIV infection, and the clinical course differs from that before the widespread use of combination antiretroviral treatment (cART). The predominant clinical feature is a subcortical dementia with deficits in the domains concentration, attention, and memory. Motor signs such as gait disturbance and impaired manual dexterity have become less prominent. Prior to the advent of cART, the cerebral dysfunction could at least partially be explained by the viral load and by virus-associated histopathological findings. In subjects where cART has led to undetectable or at least very low viral load, the pathogenic virus-brain interaction is less direct, and an array of poorly understood immunological and probably toxic phenomena are discussed. This paper gives an overview of the current concepts in the field of HAND and provides suggestions for the diagnostic and therapeutic management.

New-onset seizure in HIV-infected adult Zambians: A search for causes and consequences

OBJECTIVE

To identify the etiology of new-onset seizure in HIV-infected Zambian adults and identify risk factors for seizure recurrence.

METHODS

A prospective cohort study enrolling HIV-infected adults with new-onset seizure within 2 weeks of index seizure obtained clinical, laboratory, and neuroimaging data to determine seizure etiology. Participants were followed to identify risk factors for seizure recurrence. Risk factors for mortality were examined as mortality rates were unexpectedly high.

RESULTS

Eighty-one patients with CSF for analysis were enrolled and followed for a median of 306 days (interquartile range 61-636). Most (91%) were at WHO stage III/IV and 66 (81%) had a pre-seizure Karnofsky score ≥50. Prolonged or multiple seizures occurred in 46 (57%), including 12 (15%) with status epilepticus. Seizure etiologies included CNS opportunistic infections (OI) in 21 (26%), hyponatremia in 23 (28%), and other infections in 8 (10%). OIs included Cryptococcus (17%), JC virus (7%) and 5% each for tuberculosis, cytomegalovirus, and varicella-zoster virus. No etiology could be identified in 16 (20%). Thirty (37%) patients died during follow-up and 20 (25%) had recurrent seizures with survival being the only identifiable risk factor.

CONCLUSIONS

HIV-infected adults with new-onset seizure in Zambia often have advanced HIV disease with OI being the most frequent seizure etiology. Seizure recurrence is common but no risk factors for recurrence other than survival were identified. These findings suggest an urgent need for immune reconstitution in this population. Initiating treatment for seizure prophylaxis where only enzyme-inducing antiepileptic medications are available could threaten antiretroviral efficacy.

A Review of the Toxicity of HIV Medications II: Interactions with Drugs and Complementary and Alternative Medicine Products

For many patients today, HIV has become a chronic disease. For those patients who have access to and adhere to lifelong antiretroviral (ARV) therapy, the potential for drug-drug interactions has become a real and life-threatening concern. It is known that most ARV drug interactions occur through the cytochrome P450 (CYP) pathway. Medications for comorbid medical conditions, holistic supplements, and illicit drugs can be affected by CYP inhibitors and inducers and have the potential to cause harm and toxicity. Protease inhibitors (PIs) tend to inhibit CYP3A4, while most non-nucleoside reverse transcriptase inhibitors (NNRTIs) tend to induce the enzyme. As such, failure to adjust the dose of co-administered medications, such as statins and steroids, may lead to serious complications including rhabdomyolysis and hypercortisolism, respectively. Similarly, gastric acid blockers can decrease several ARV absorption, and warfarin doses may need to be adjusted to maintain therapeutic concentrations. Illicit drugs such as methylenedioxymethamphetamine (MDMA, "ecstasy") in combination with PIs lead to increased toxicity, while the concomitant administration of sedative drugs such as midazolam and alprazolam in patients taking PIs can result in prolonged sedation, delayed recovery, and increased length of stay. Even supplements like St. John's Wort can alter PI concentrations. In theory, any drug that is metabolized by CYP has potential for a pharmacokinetic drug-drug interaction with all PIs, cobicistat, and most NNRTIs. When adding a new medication to an ARV regimen, use of a drug-drug interaction software and/or consultation with a clinical pharmacist/pharmacologist or HIV specialist is recommended.

Early antiretroviral therapy is protective against epilepsy in children with human immunodeficiency virus infection in botswana

BACKGROUND

Seizures are common among patients with HIV/AIDS in the developing world and are associated with significant morbidity and mortality. Early treatment with combination antiretroviral therapy (cART) may reduce this risk by decreasing rates of central nervous system infections and HIV encephalopathy.

METHODS

A case-control study of new-onset epilepsy among children aged 0-18 years with perinatally acquired HIV/AIDS followed in Gaborone, Botswana, during the period 2003-2009 was conducted. Children with epilepsy were identified and compared with age- and sex-matched controls without epilepsy with respect to timing of cART initiation. Early treatment was defined as treatment with cART before the age of 12 months, at a CD4% of greater than 25 in children aged 1-5 years, or at an absolute CD4 count of >350 cell per cubic millimeter in children aged 5 years and older.

RESULTS

We identified 29 cases of new-onset epilepsy and 58 age- and sex-matched controls. The most common identified etiologies for epilepsy were central nervous system infections and direct HIV neurotoxicity. Only 8 (28%) of the children who developed epilepsy received early treatment compared with 31 (53%) controls (odds ratio: 0.36, 95% confidence interval: 0.14 to 0.92, P = 0.03). This effect was primarily driven by differences in rates of epilepsy among children who initiated treatment with cART between the ages of 1 and 5 years (11% vs. 53%, odds ratio: 0.11, 95% confidence interval: 0.01 to 1.1, P = 0.06).

CONCLUSIONS

Earlier initiation of cART may be protective against epilepsy in children with HIV.

[HIV 1-associated neurocognitive disorder: current epidemiology, pathogenesis, diagnosis and management]

By restoring the immunological function the modern antiretroviral treatment of human immunodeficiency virus (HIV-1) infection has considerably lowered the incidence of opportunistic infections. As opposed to the classical manifestations of HIV-induced immunosuppression the incidence and prevalence of HIV-associated neurocognitive disorders (HAND) has not noticeably decreased and HAND continues to be relevant in daily clinical practice. At present, HAND occurs in earlier stages of HIV infection, and the clinical course differs from that before the introduction of combination antiretroviral treatment (cART). The predominant clinical manifestation is a subcortical dementia with deficits in the domains attention, concentration and memory. Signs of central motor pathway lesions have become less frequent and less prominent. Prior to the advent of cART the cerebral dysfunction could at least partially be explained by the viral load and by virus-associated histopathological findings. In patients with at least partially successfully treated infections, this relationship no longer exists, but a plethora of poorly understood immunological and probably toxic phenomena are under discussion.This consensus paper summarizes the progress made in the last 12 years in the field of HAND and provides suggestions for the diagnostic and therapeutic management.

Clinical features of seizures in patients with human immunodeficiency virus infection

Patients with human immunodeficiency virus (HIV) infection have a higher burden of seizures, but few studies have examined seizures in HIV-infected individuals in Korea. A retrospective study was conducted to determine the epidemiology and clinical characteristics of seizures in patients with HIV infection. Among a total of 1,141 patients, 34 (3%) had seizures or epilepsy; 4 of these individuals had epilepsy before HIV infection, and the others showed new-onset seizures. Most patients exhibited moderate (200 to 500, n = 13) or low (below 200, n = 16) CD4 counts. The most common seizure etiology was progressive multifocal leukoencephalopathy (n = 14), followed by other HIV-associated central nervous system (CNS) complications (n = 6). Imaging studies revealed brain lesions in 21 patients. A total of 9 patients experienced only one seizure during the follow-up period, and 25 patients experienced multiple seizures or status epilepticus (n = 2). Multiple seizures were more common in patients with brain etiologies (P = 0.019) or epileptiform discharges on EEG (P = 0.032). Most seizures were controlled without anticonvulsants (n = 12) or with a single anticonvulsant (n = 12). Among patients with HIV infection, seizures are significantly more prevalent than in the general population. Most seizures, with the exception of status epilepticus, have a benign clinical course and few complications.

Epilepsia Partialis Continua as Presenting Manifestation of AIDS: A Rarity

Seizures, most commonly generalized tonic-clonic, are common in known human immune deficiency virus (HIV) sero-positive patients, and they usually have a focal lesion on brain imaging. However, it is very unusual to see a patient with no premorbid illness presenting with epilepsia partialis continua (EPC) and then being detected HIV seropositive with an Acquired Immune Deficiency Syndrome (AIDS)-defining illness. We report the case of a teenaged boy with no past significant history or known high-risk behavior who presented with recurrent focal seizures of 5 days' duration, EPC, and encephalopathy. His electroencephalogram showed periodic lateralized epileptiform discharges (PLEDS), and magnetic resonance imaging (MRI) of the brain showed abnormal signal changes in the right parieto-occipital cortex and thalamus, both as yet unreported in cytomegalovirus (CMV) encephalitis, which was diagnosed by the cerebrospinal fluid (CSF) analysis.

Unexpected finding of delayed-onset seizures in HIV-positive, treatment-experienced subjects in the Phase IIb evaluation of fosdevirine (GSK2248761)

BACKGROUND

Fosdevirine (GSK2248761) is a non-nucleoside reverse transcriptase inhibitor with HIV-1 activity against common efavirenz-resistant strains. Two partially blind, randomized, Phase IIb studies were initiated (1 in treatment-naive and 1 in treatment-experienced subjects with HIV) to select a once-daily dose of fosdevirine for Phase III trials.

METHODS

In the SIGNET study, treatment-naive subjects were randomized 1:1:1 to receive once-daily fosdevirine 100 or 200 mg or efavirenz 600 mg, each along with tenofovir disoproxil fumarate/emtricitabine 300 mg/200 mg or abacavir/lamivudine 600 mg/300 mg. In the SONNET study, treatment-experienced subjects with non-nucleoside reverse transcriptase inhibitor-resistant HIV-1 were randomized 1:1:1 to treatment with fosdevirine 100 or 200 mg once daily or etravirine 200 mg twice daily, each along with twice-daily darunavir/ritonavir 600/100 mg and raltegravir 400 mg. The primary efficacy end point was the proportion of subjects with HIV-1 RNA<50 copies/ml. Safety and pharmacokinetics were also addressed.

RESULTS

A total of 35 subjects were exposed to fosdevirine 100 or 200 mg. Trials were halted when 5 treatment-experienced subjects (1 receiving fosdevirine 100 mg, 4 receiving fosdevirine 200 mg) developed new-onset seizures after ≥4 weeks of exposure to fosdevirine. There was no clear association between seizures and fosdevirine plasma drug levels. Time to seizure onset ranged from 28 to 81 days, and all 5 subjects experienced ≥1 seizure after drug discontinuation.

CONCLUSIONS

The delayed onset of seizures after fosdevirine exposure and persistence after discontinuation is without precedent in antiretroviral drug development, leading to additional investigation and underscoring the need for careful subject monitoring.

Safe Treatment of Seizures in the Setting of HIV/AIDS

OPINION STATEMENT

HIV(+) patients are at increased risk for developing seizures due to the vulnerability of the central nervous system to HIV-associated diseases, immune dysfunction, and metabolic disturbances. In patients with acute seizures, standard protocols still apply with urgent seizure cessation being the priority. Management of the person with established epilepsy who contracts HIV is challenging, but the decision to initiate chronic antiepileptic drug (AED) therapy in an HIV(+) patient is also difficult. Chronic treatment guidelines emphasize the interactions between AEDs and antiretroviral (ARV) medications, but provide no explicit advice regarding when to initiate an AED, what medication to select, and/or the duration of treatment. Epidemiologic data regarding seizure recurrence risk in HIV(+) individuals is not available. The risk of further seizures likely depends upon the underlying etiology for the seizure(s) and patients' immune status and may be increased by the use of efavirenz (an ARV). The issues for consideration include AED-ARV interactions, organ dysfunction, seizure type, and drug side effects, which may worsen or be confused with symptoms of HIV and/or epilepsy. Co-administration of enzyme inducing (EI)-AEDs and ARVs can result in virological failure, breakthrough seizure activity, AED toxicity, and/or ARV toxicity. Where available, the AED of choice in HIV(+) patients is levetiracetam due to its broad spectrum activity, ease of use, minimal drug interactions, and favorable side effect profile. Lacosamide, gabapentin, and pregabalin are also favored choices in patients with partial onset seizures and/or those failing levetiracetam. Where newer AEDs are not available, valproic acid may be the treatment of choice in terms of an AED, which will not cause enzyme induction-associated ARV failure, but its side effect profile causes other obvious problems. In resource-limited settings (RLS) where only EI-AEDs are available, there are no good treatment options and further pressure needs to be placed upon policymakers to address this care gap and public health threat.

The impact of enzyme-inducing antiepileptic drugs on antiretroviral drug levels: a case-control study

PURPOSE

To evaluate the impact of enzyme-inducing antiepileptic drugs (EI-AEDs) on serum antiretroviral (ARV) levels in patients with HIV.

METHODS

Data from the U.S. Military HIV Natural History Study were screened to identify participants taking ARVs with EI-AEDs and controls taking ARVs with non enzyme-inducing AEDs (NEI-AEDs). The proportion of serum ARV levels below the recommended minimum concentrations (C(min)) was compared between these groups.

RESULTS

ARV levels were available for 10 individuals exposed to 16 intervals on combined ARVs/EI-AEDs (phenytoin and carbamazepine) and for 25 controls exposed to 30 overlap intervals on combined ARVs/NEI-AEDs. The percentage of overlap intervals with ≥1 ARV levels below C(min) was higher in the EI-AED group than in controls (37.5% vs. 23.3%; p=0.124). After excluding intervals associated with serum levels of EI-AEDs below the reference range (n=6), the proportion of intervals with ≥1 ARV level below C(min) was significantly greater among EI-AED recipients (60%) compared to controls (23.3%; p=0.008).

CONCLUSIONS

ARV levels below C(min) were more common in participants receiving EI-AEDs, the difference being statistically significant for intervals associated with EI-AED levels within the reference range. These data suggest that, in agreement with current guidelines, EI-AEDs should be avoided in patients receiving ARV therapy.

Evidence-based guideline: Antiepileptic drug selection for people with HIV/AIDS: report of the Quality Standards Subcommittee of the American Academy of Neurology and the Ad Hoc Task Force of the Commission on Therapeutic Strategies of the International League Against Epilepsy

OBJECTIVE

To develop guidelines for selection of antiepileptic drugs (AEDs) among people with HIV/AIDS.

METHODS

The literature was systematically reviewed to assess the global burden of relevant comorbid entities, to determine the number of patients who potentially utilize AEDs and antiretroviral agents (ARVs), and to address AED-ARV interactions.

RESULTS AND RECOMMENDATIONS

AED-ARV administration may be indicated in up to 55% of people taking ARVs. Patients receiving phenytoin may require a lopinavir/ritonavir dosage increase of ~50% to maintain unchanged serum concentrations (Level C). Patients receiving valproic acid may require a zidovudine dosage reduction to maintain unchanged serum zidovudine concentrations (Level C). Coadministration of valproic acid and efavirenz may not require efavirenz dosage adjustment (Level C). Patients receiving ritonavir/atazanavir may require a lamotrigine dosage increase of ∼50% to maintain unchanged lamotrigine serum concentrations (Level C). Coadministration of raltegravir/atazanavir and lamotrigine may not require lamotrigine dosage adjustment (Level C). Coadministration of raltegravir and midazolam may not require midazolam dosage adjustment (Level C). Patients may be counseled that it is unclear whether dosage adjustment is necessary when other AEDs and ARVs are combined (Level U). It may be important to avoid enzyme-inducing AEDs in people on ARV regimens that include protease inhibitors or nonnucleoside reverse transcriptase inhibitors, as pharmacokinetic interactions may result in virologic failure, which has clinical implications for disease progression and development of ARV resistance. If such regimens are required for seizure control, patients may be monitored through pharmacokinetic assessments to ensure efficacy of the ARV regimen (Level C).

Virologic outcomes of HAART with concurrent use of cytochrome P450 enzyme-inducing antiepileptics: a retrospective case control study

BACKGROUND

To evaluate the efficacy of highly-active antiretroviral therapy (HAART) in individuals taking cytochrome P450 enzyme-inducing antiepileptics (EI-EADs), we evaluated the virologic response to HAART with or without concurrent antiepileptic use.

METHODS

Participants in the US Military HIV Natural History Study were included if taking HAART for ≥6 months with concurrent use of EI-AEDs phenytoin, carbamazepine, or phenobarbital for ≥28 days. Virologic outcomes were compared to HAART-treated participants taking AEDs that are not CYP450 enzyme-inducing (NEI-AED group) as well as to a matched group of individuals not taking AEDs (non-AED group). For participants with multiple HAART regimens with AED overlap, the first 3 overlaps were studied.

RESULTS

EI-AED participants (n = 19) had greater virologic failure (62.5%) compared to NEI-AED participants (n = 85; 26.7%) for the first HAART/AED overlap period (OR 4.58 [1.47-14.25]; P = 0.009). Analysis of multiple overlap periods yielded consistent results (OR 4.29 [1.51-12.21]; P = 0.006). Virologic failure was also greater in the EI-AED versus NEI-AED group with multiple HAART/AED overlaps when adjusted for both year of and viral load at HAART initiation (OR 4.19 [1.54-11.44]; P = 0.005). Compared to the non-AED group (n = 190), EI-AED participants had greater virologic failure (62.5% vs. 42.5%; P = 0.134), however this result was only significant when adjusted for viral load at HAART initiation (OR 4.30 [1.02-18.07]; P = 0.046).

CONCLUSIONS

Consistent with data from pharmacokinetic studies demonstrating that EI-AED use may result in subtherapeutic levels of HAART, EI-AED use is associated with greater risk of virologic failure compared to NEI-AEDs when co-administered with HAART. Concurrent use of EI-AEDs and HAART should be avoided when possible.

The uncommon causes of status epilepticus: a systematic review

This paper reports the first systematic review of uncommon causes of status epilepticus reported in the literature between 1990 and 2008. Uncommon causes are defined as those not listed in the main epidemiological studies of status epilepticus. 181 causes were identified. These were easily categorised into 5 specific aetiological categories: immunological disorders, mitochondrial disorders, infectious diseases, genetic disorders and drugs/toxins. A sixth category of 'other causes' has also been included. Knowledge of these causes is important for clinical management and treatment, and also for a better understanding of the pathophysiology of status epilepticus.

Seizure management in a complex hospice patient

Antiepileptic medication use in noncancer hospice/palliative care patients is not well defined. The authors report the case of a human immunodeficiency virus (HIV) patient under hospice care with increased seizure frequency. The patient is a 22-year-old female with advanced HIV disease complicated by tonic-clonic seizures, hypoalbuminemia, gastroesophageal reflux disease (GERD), and gastritis. During an admission to the hospice inpatient unit, she developed increasing seizure frequency while receiving oral phenytoin. After collaboration between the clinical pharmacist and the hospice treating physician, they simplified her medication regimen, discontinued the phenytoin, and initiated oral levetiracetam. After these adjustments to her medication regimen, the patient's seizure frequency decreased significantly. This case illustrates the challenges of anticonvulsant use in advanced disease, including drug-drug interactions, impaired pharmacokinetics parameters, and increased risk of adverse effects. The importance of continuously monitoring patients for adverse drug events and assessing patient specific factors to help guide medication selection are also highlighted.

New onset seizures in HIV--seizure semiology, CD4 counts, and viral loads

Thirty-seven HIV-positive patients with new-onset seizures (NOS) were prospectively identified during a 1-year study period. The patients were categorized according to the different mechanisms causing NOS in HIV, namely focal brain lesion (FBL) in 21 patients (57%), meningitis in 6 patients (16%), metabolic derangement (no patient), and no identified cause (NIC) other than HIV itself (10 patients, 27%). Seizure semiology, CD4 counts, and blood and cerebral spinal fluid (CSF) viral loads were studied to identify any special characteristics of the different categories. With respect to seizure semiology, all NIC patients had generalized seizures. Two-thirds of the meningitis patients had generalized seizures with one-third having focal seizures. Half of the patients with FBL had generalized seizures and one-third had focal seizures. Status epilepticus was strongly associated with FBL. No significant difference could be detected between the subgroups with respect to CD4 counts and serum and CSF viral loads. The median CD4 count in all patients was 108 cells/ml, indicating advanced immunosuppression. In the FBL group this was 104 cells/ml. In the meningitis group the median CD4 count was 298 cells/ml, and in the NIC group this was 213 cells/ml. Similarly, no differences were noted in the NOS categories with respect to serum and CSF viral loads. Seizures in HIV are a nonspecific manifestation of the seizure mechanism.

Frequency of seizures and epilepsy in neurological HIV-infected patients

BACKGROUND

Infection with the human immunodeficiency virus (HIV) is associated both with infections of the central nervous system and with neurological deficits due to direct effects of the neurotropic virus. Seizures and epilepsy are not rare among HIV-infected patients. We investigated the frequency of acute seizures and epilepsy of patients in different stages of HIV infection. In addition, we compared the characteristics of patients who experienced provoked seizures only with those of patients who developed epilepsy.

METHODS

The database of the Department of Neurology, University of Münster, was searched for patients with HIV infection admitted between 1992 and 2004. Their charts were reviewed regarding all available sociodemographic, clinical, neurophysiological, imaging and laboratory data, therapy and outcome. Stage of infection according to the CDC classification and the epileptogenic zone were determined.

RESULTS

Of 831 HIV-infected patients treated in our department, 51 (6.1%) had seizures or epilepsy. Three of the 51 patients (6%) were diagnosed with epilepsy before the onset of the HIV infection. Fourteen patients (27%) only had single or few provoked seizures in the setting of acute cerebral disorders (eight patients), drug withdrawal or sleep withdrawal (two patients), or of unknown cause (four patients). Thirty-four patients (67%) developed epilepsy in the course of their HIV infection. Toxoplasmosis (seven patients), progressive multifocal leukencephalopathy (seven patients) and other acute or subacute cerebral infections (five patients) were the most frequent causes of seizures. EEG data of 38 patients were available. EEG showed generalized and diffuse slowing only in 9 patients, regional slowing in 14 patients and regional slowing and epileptiform discharges in 1 patient. Only 14 of the patients had normal EEG. At the last contact, the majority of the patients (46 patients=90%) were on highly active antiretroviral therapy (HAART). Twenty-seven patients (53%) were on anticonvulsant therapy (gabapentin: 14 patients, carbamazepine: 9 patients, valproate: 2 patients, phenytoin: 1 patient, lamotrigine: 1 patient). Patients with only provoked seizures had no epilepsy risk factors except HIV infection, and were less likely to be infected via intravenous drug abuse.

CONCLUSIONS

Seizures are a relevant neurological symptom during the course of HIV infection. Although in some patients seizures only occur provoked by acute disease processes, the majority of patients with new onset seizures eventually develops epilepsy and require anticonvulsant therapy. Intravenous drug abuse and the presence of non-HIV-associated risk factors for epilepsy seem to be associated with the development of chronic seizures in this patient group.

Progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) was a rare disease until the advent of the HIV/AIDS pandemic. Recent interest in the disorder has been spurred by its appearance in patients treated with the monoclonal antibodies natalizumab and rituximab. Unless the accompanying underlying immune deficit can be reversed, PML typically progresses to death fairly rapidly. Treatment directed against the JC virus has been unhelpful, but an increased understanding of disease pathogenesis may result in effective therapeutic strategies.

Mechanisms of Pharmacokinetic and Pharmacodynamic Drug Interactions Associated with Ritonavir-Enhanced Tipranavir

Tipranavir is a nonpeptidic protease inhibitor that has activity against human immunodeficiency virus strains resistant to multiple protease inhibitors. Tipranavir 500 mg is coadministered with ritonavir 200 mg. Tipranavir is metabolized by cytochrome P450 (CYP) 3A and, when combined with ritonavir in vitro, causes inhibition of CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A in addition to induction of glucuronidase and the drug transporter P-glycoprotein. As a result, drug-drug interactions between tipranavir-ritonavir and other coadministered drugs are a concern. In addition to interactions with other antiretrovirals, tipranavir-ritonavir interactions with antifungals, antimycobacterials, oral contraceptives, statins, and antidiarrheals have been specifically evaluated. For other drugs such as antiarrhythmics, antihistamines, ergot derivatives, selective serotonin receptor agonists (or triptans), gastrointestinal motility agents, erectile dysfunction agents, and calcium channel blockers, interactions can be predicted based on studies with other ritonavir-boosted protease inhibitors and what is known about tipranavir-ritonavir CYP and P-glycoprotein utilization. The highly complex nature of drug interactions dictates that cautious prescribing should occur with narrow-therapeutic-index drugs that have not been specifically studied. Thus, the known interaction potential of tipranavir-ritonavir is reported, and in vitro and in vivo data are provided to assist clinicians in predicting interactions not yet studied. As more clinical interaction data are generated, better insight will be gained into the specific mechanisms of interactions with tipranavir-ritonavir.

Treatment strategies after a single seizure : rationale for immediate versus deferred treatment

What is the rationale for the treatment of an epileptic seizure? More specifically, should a first seizure be treated as soon as it is diagnosed or should one defer treatment until a second seizure occurs? Several studies indicate that the risk of a second (unprovoked) seizure is <50%, but studies vary in methodology and most have reviewed outcome in children only. Also, many patients were maintained on antiepileptic drugs (AEDs) during these studies, meaning that the risk for seizure recurrence was perhaps underestimated compared with the risk if untreated. Most neurologists recommend waiting for a second seizure in order to avoid complications of medications that might prove to be unnecessary. Several large studies show that delaying treatment until a second seizure occurs does not worsen the course of epilepsy or likelihood of eventual seizure control. Seizures attributable to an acute illness ('acute symptomatic', provoked seizures) usually resolve with treatment of the underlying illness and thus long-term AEDs are often unwarranted. Nevertheless, seizures arising in certain circumstances are more likely to recur and there are special considerations for patients with strokes, tumours, infections and dementia, and also after head injury or neurosurgery. Patient preferences with regard to risk and benefit also enter into the decision on whether to initiate AED treatment after a single seizure.

Usefulness of monitoring free (unbound) concentrations of therapeutic drugs in patient management

Drugs are bound to various serum proteins in different degrees and only unbound or free drug is pharmacologically active. Although free drug concentration can be estimated from total concentration, for strongly bound drugs, prediction of free level is not always possible. Conditions like uremia, liver disease and hypoalbuminemia can lead to significant increases in free drug resulting in drug toxicity even if the concentration of total drug is within therapeutic range. Drug-drug interactions may also lead to a disproportionate increase in free drug concentrations. Elderly patients may have increased free drug concentrations due to hypoalbuminemia. Elevated free phenytoin concentrations have also been reported in patients with AIDS and pregnancy. Currently free drug concentrations of anticonvulsants such as phenytoin, carbamazepine and valproic acid are widely measured in clinical laboratories. Newer drugs such as mycophenolic acid mofetil and certain protease inhibitors are also considered as candidates for monitoring free drug concentration.

Increased adverse drug reactions to antimicrobials and anticonvulsants in patients with HIV infection

OBJECTIVE

To review the incidence, signs, symptoms, and mechanisms of adverse drug reactions (ADRs) to sulfonamides, anticonvulsants, and antimycobacterial medications among people with HIV.

DATA SOURCES

Searches of MEDLINE/PubMed (1980-November 2005) and National Library of Medicine Meeting Abstracts (1989-November 2005), as well as hand searches of journals and abstracts, were conducted to identify primary literature. Reference lists were reviewed to identify additional relevant reports.

STUDY SELECTION AND DATA EXTRACTION

Relevant articles and abstracts, particularly of in vitro experiments and clinical studies, were compiled and reviewed.

DATA SYNTHESIS

ADRs, especially in HIV-infected patients, are a cause for concern. Sulfonamides, anticonvulsants, and antimycobacterial drugs are commonly used to prevent and treat complications of HIV, including seizures and opportunistic infections. Patients with HIV have a much greater rate of ADRs to these drug classes, including severe and life-threatening hypersensitivity reactions. Several mechanisms of these ADRs have been postulated. Sulfamethoxazole and anticonvulsant hypersensitivity may involve the increased formation and decreased detoxification of reactive metabolites. The mechanisms for the marked increase in hypersensitivity ADRs to antimycobacterial drugs may be related to an altered immune profile in patients infected with both tuberculosis and HIV.

CONCLUSIONS

ADRs to antimicrobial and anticonvulsant therapy cause markedly increased morbidity and mortality in HIV-positive patients. Further research involving the interaction between HIV and the increased ADRs to these drugs is required.

Modulation of human immunodeficiency virus infection by anticonvulsant drugs

Patients with human immunodeficiency virus (HIV) infection often require treatment with anticonvulsants either for treatment of seizures or occasionally for pain control. In this study, the authors determined if the anticonvulsants phenytoin, carbamazepine, and valproate could modulate HIV replication. These drugs activated HIV replication in latently infected monocytic cells but not in latently infected lymphocytic cells at clinically relevant dosages. The activation in the monocytic cells was as a result of transactivation of HIV long terminal repeat (LTR) and could be seen at therapeutic dosages whereas no effect was seen on LTR activation in lymphocytic cells. When the drugs were used in conjunction with known transactivators of HIV LTR such as Tat and phorbol-12-myristate-13-acetate (PMA), no additive or synergistic effect was noted. Although the clinical relevance of these observations needs to be determined, these observations may suggest that monitoring of cerebrospinal fluid (CSF) viral load maybe needed in HIV-infected patients treated with anticonvulsants, because HIV-infected macrophages are important in mediating HIV dementia.

Seizures in HIV/AIDS: a southern African perspective

South Africa, with a population of 44.8 million, has over 5 million human immunodeficiency virus (HIV)-infected individuals. Over 70% of HIV-infected patients will present with clinically relevant neurologic disease at some stage during the course of their disease. New onset seizures occur in 3-11% of these patients. The mechanism of seizure production in HIV-positive patients includes incidental association, HIV itself, opportunistic infections (OIs), neoplasia, cerebrovascular disease, drug toxicity, and metabolic derangements. In developing countries, OIs constitute the largest group presenting with seizures. Seizure management in HIV-positive patients presents special problems, especially with respect to drug-disease and drug-drug interactions. The older antiepileptic drugs (AEDs) are protein-bound and largely depend on the cytochrome p450 system for their metabolism. The newer AEDs may be safer in patients on antiretroviral drugs. However, they are expensive, an important consideration in developing countries.

Administration of HDAC inhibitors to reactivate HIV-1 expression in latent cellular reservoirs: implications for the development of therapeutic strategies

The discovery of powerful antiviral compounds in the 90's raised the hope that the human immunodeficiency virus type 1 (HIV-1) might be eradicated. However, if these drugs succeed in decreasing and controlling viral replication, complete eradication of the virus is nowadays impossible. The persistence of virus even after long periods of highly active antiretroviral therapy (HAART) mainly results from the presence of cellular reservoirs that contain transcriptionally competent latent viruses capable of producing infectious particles after cellular activation. These latently infected cells are a permanent source for virus reactivation and lead to a rebound of the viral load after interruption of HAART. Activation of HIV gene expression in these cells combined with an effective HAART has been proposed as an adjuvant therapy that could lead to the elimination of the latently infected cells and then to the eradication of the infection. In this context, we have previously demonstrated that deacetylase inhibitors (HDACi) synergize with TNF-induced NF-kappaB to activate the HIV-1 promoter. The physiological relevance of the TNF/HDACi synergism was shown on HIV-1 replication in both acutely and latently HIV-infected cell lines. Based on these results, we propose the administration of deacetylase inhibitor(s) together with continuous HAART as a new potential therapeutic perspective to decrease the pool of latent HIV reservoirs by forcing viral expression.

Coadministration of Lopinavir/Ritonavir and Phenytoin Results in Two-Way Drug Interaction Through Cytochrome P-450 Induction

Lopinavir/ritonavir (LPV/RTV) is a CYP3A4 inhibitor and substrate; it also may induce cytochrome P-450 (CYP) isozymes. Phenytoin (PHT) is a CYP3A4 inducer and CYP2C9/CYP2C19 substrate. This study quantified the pharmacokinetic (PK) drug interaction between LPV/RTV and PHT. Open-label, randomized, multiple-dose, PK study in healthy volunteers. Subjects in arm A (n = 12) received LPV/RTV 400/100 mg twice daily (BID) (days 1-10), followed by LPV/RTV 400/100 mg BID + PHT 300 mg once daily (QD) (days 11-22). Arm B (n = 12) received PHT 300 mg QD (days 1-11), followed by PHT 300 mg QD + LPV/RTV 400/100 mg BID (days 12-23). Plasma samples were collected on day 11 and day 22; PK parameters were compared by geometric mean ratio (GMR, day 22:day 11). P values <0.05 were considered significant. Following PHT addition, LPV area under the concentration-time curve (AUC0-12h) decreased from 70.9 +/-37.0 to 49.6 +/- 25.1 microg.h/mL (GMR 0.67, P = 0.011) and C0h decreased from 6.0 +/- 3.2 to 3.6 +/- 2.3 microg/mL (GMR 0.54, P = 0.001). Following LPV/RTV addition, PHT AUC0-24h decreased from 191.0+/-89.2 to 147.8+/-104.5 microg.h/mL (GMR 0.69, P = 0.009) and C0h decreased from 7.0+/-4.0 to 5.3+/-4.1 microg/mL (GMR 0.66, P = 0.033). Concomitant LPV/RTV and PHT use results in a 2-way drug interaction. Phenytoin appears to increase LPV clearance via CYP3A4 induction, which is not offset by the presence of low-dose RTV. LPV/RTV may increase PHT clearance via CYP2C9 induction. Management should be individualized to each patient; dosage or medication adjustments may be necessary.

Anticonvulsant and antiretroviral interactions

OBJECTIVE

To evaluate the clinical significance of interactions between anticonvulsant and antiretroviral agents and provide recommendations regarding their concurrent use.

DATA SOURCES

A PubMed search (1966 to April 2003) was conducted using individual anticonvulsant and antiretroviral drug names and the following key search terms: anticonvulsant, antiepileptic, antiretroviral, protease inhibitor, and pharmacokinetic. Abstracts from scientific meetings that pertained to drug interactions were manually reviewed.

STUDY SELECTION AND DATA EXTRACTION

All articles identified by the PubMed search were examined. Articles and abstracts from scientific meetings with relevant information were included.

DATA SYNTHESIS

Six case reports were identified that describe interactions between anticonvulsant agents and protease inhibitors. In several reports, carbamazepine serum concentrations increased by approximately two- to threefold with concurrent ritonavir, resulting in carbamazepine-related toxicity. Carbamazepine was also associated with loss of viral suppression when combined with indinavir. Phenytoin serum concentrations were decreased with nelfinavir in a patient who developed recurrent seizures. The effect of ritonavir on phenytoin was variable; a 30% reduction in phenytoin serum concentration occurred in one patient, while no apparent change was observed in another. Interactions with nonnucleoside reverse-transcriptase inhibitors are poorly characterized because existing data involve concurrent protease inhibitor therapy. The utility of newer anticonvulsant agents is explored. Experience with newer anticonvulsant agents in 2 patients at our site is also described.

CONCLUSIONS

Limited data exist regarding interactions between anticonvulsant and antiretroviral agents. Valproic acid and newer anticonvulsant agents may provide useful alternatives to first-generation agents. Clinicians need to be diligent when monitoring for anticonvulsant-antiretroviral interactions because of the potential for toxicity, loss of seizure control, and incomplete viral suppression.