Evaluation of the concentrations of psychotropic drugs in HIV-infected versus HIV-negative patients: Potential implications for clinical practice

Polypharmacy and Aging in People Living with HIV: 6 Years of Experience in a Multidisciplinary Outpatient Clinic

BACKGROUND

Despite the availability of potent antiretroviral drugs, the management of human immunodeficiency virus (HIV) infection still presents some important challenges, especially in older patients who often experience age-related comorbidities and complex polypharmacy.

OBJECTIVE

To describe the results of our 6 year experience with the outpatient clinic [Gestione Ambulatoriale Politerapie (GAP)] for the management of polypharmacy in people living with HIV (PLWH).

METHODS

Demographic characteristics, antiretroviral regimens, and number and type of comedications were collected in all PLWH included in the database of GAP from September 2016 to September 2022. Therapies were stratified based on the number of anti-HIV drugs (dual versus triple regimens) and on the presence of pharmacokinetic boosters (ritonavir or cobicistat).

RESULTS

A total of 556 PLWH were included in the GAP database. Overall, the enrolled patients were administered 4.2 ± 2.7 drugs (range 1-17) in addition to antiretroviral therapies. The number of comedications greatly increased with age (3.0 ± 2.2 versus 4.1 ± 2.5 versus 6.3 ± 3.2 in PLWH aged < 50 versus 50-64 versus > 65 years; p < 0.001 for all comparisons). PLWH on dual antiretroviral therapies were significantly older (58 ± 9 versus 54 ± 11 years; p < 0.001) and were concomitantly treated with more drugs (5.1 ± 3.2 versus 3.8 ± 2.5; p < 0.001) compared with those on triple therapies. A significant reduction of boosted antiretroviral regimens (53% versus 23%; p < 0.001) and in the number of comedications (4.0 ± 2.9 versus 3.1 ± 2.2 drugs; p < 0.001) was observed in the subgroup of patients (n = 198) with two GAP visits.

CONCLUSIONS

The high prevalence of polypharmacy in PLWH, especially among older adults, place these patients at high risk for clinically relevant drug-drug interactions (DDIs). A multidisciplinary approach involving physicians and clinical pharmacologists could help to optimize medication regimens associated with reduced risk.

Management of diabetes mellitus in people living with HIV: A single-center experience

Background: Diabetes mellitus (DM) is more common in people living with HIV (PLWH) than in HIV-negative patients. Here we aimed to describe the response of PLWH with DM to glucose-lowering therapies in a reference hospital of northern Italy. Setting: 200 PLWH and DM were identified from the database of our clinic. Methods: Good control of DM was defined as having fasting glucose <130 mg/dl or HbA1c < 53 mmol/mol. The distribution of glucose-lowering therapies in PLWH was compared with that of HIV-negative patients with DM. Results: Mean total fasting glucose and HbA1C were 143 ± 50 mg/dl (51% exceeding the 130 mg/dl cutoff) and 51 ± 16 mmol/mol (30% exceeding the 53 mmol/mol cutoff), respectively. PLWH were less treated with dipeptidyl peptidase-4 inhibitors (1.7% versus 9.6%, p < 0.01) and sulfonylureas (3.3% versus 13.2%, p < 0.01), being conversely more frequently treated with metformin (53.8% versus 37.7%, p < 0.01), glifozins plus metformin (7.1% versus 2.0%, p < 0.05) or insulin plus other glucose-lowering agents (5.5% versus 0.5%, p < 0.01). Conclusion: An underuse of dipeptidyl peptidase-4 inhibitors was found which was, however, counterbalanced by a higher use of combination of drugs (including glifozins). A rational assessment of drug-drug interactions would contribute to a better selection of the best glucose lowering agent for each antiretroviral therapy.

Real-life management of drug-drug interactions between antiretrovirals and statins

BACKGROUND

PIs cause drug-drug interactions (DDIs) with most statins due to inhibition of drug-metabolizing enzymes and/or the hepatic uptake transporter OATP1B1, which may alter the pharmacodynamic (PD) effect of statins.

OBJECTIVES

To assess the management of DDIs between antiretrovirals (ARVs) and statins in people living with HIV (PLWH) considering statin plasma concentrations, compliance with dosing recommendations and achievement of lipid targets.

METHODS

PLWH of the Swiss HIV Cohort Study were eligible if they received a statin concomitantly with ARVs. HDL, total cholesterol (TC) and statin plasma concentration were measured during follow-up visits. Individual non-HDL and TC target values were set using the Framingham score and the 2018 European AIDS Clinical Society recommendations.

RESULTS

Data were analysed for rosuvastatin (n = 99), atorvastatin (n = 92), pravastatin (n = 46) and pitavastatin (n = 21). Rosuvastatin and atorvastatin underdosing frequently led to suboptimal PD response. Insufficient lipid control was observed with PIs despite high atorvastatin concentrations, likely explained by inhibition of OATP1B1 resulting in less statin uptake in the liver. Target lipid values were more often achieved with unboosted integrase inhibitors due to both their favourable DDI profiles and neutral effect on lipids. Insufficient lipid control was common with pravastatin and pitavastatin regardless of co-administered ARVs and despite using maximal recommended statin doses. The latter suggests lower efficacy compared with rosuvastatin or atorvastatin.

CONCLUSIONS

Suboptimal management of DDIs with statin underdosing was observed in 29% of prescriptions. Integrase inhibitor-based regimens and/or treatment with rosuvastatin or atorvastatin should be favoured in patients with refractory dyslipidaemia.

Therapeutic drug monitoring and pharmacogenetics of antipsychotics and antidepressants in real life settings: A 5-year single centre experience

OBJECTIVES

Exposure and clinical response to CNS drugs are largely variable. AGNP guidelines suggest therapy individualisation with therapeutic drug monitoring of plasma concentrations and pharmacogenetic testing. We present the retrospective analysis of the last 5 years' data collected in real life settings as indirect evidence of the applications of the AGNP guidelines in the routine clinical management of psychiatric patients requiring pharmacologic treatments.

METHODS

Plasma concentrations were quantified using a liquid chromatography/tandem mass spectrometry method. Genomic DNA was isolated using an automatic DNA extraction system. All genotypes were determined by Real-Time PCR.

RESULTS

We collected a total of 4582 requests for TDM and 212 requests for pharmacogenetic analysis. A wide distribution in the trough concentrations was observed for most drugs indicating a high interpatient variability. Nearly 45% of the samples had trough levels below the minimum effective drug concentrations set by the AGNP guidelines; only 8% of the samples had high concentrations. For pharmacogenetics analysis, among antipsychotics, clozapine, haloperidol and aripiprazole were the most requested (78%); while for antidepressants SSRIs were the most frequently prescribed.

CONCLUSIONS

These data suggest that physicians are becoming more confident with the laboratory pharmacologic tools to optimise treatments and/or that the pharmacological treatment of patients with psychiatric disorders is becoming more challenging. TDM and PGx might significantly contribute to the rational selection of the best drug and best dose in individual cases.

Assessment of Antiepileptic Drug Concentrations in HIV-Infected versus HIV-Negative Patients: A Retrospective Analysis

INTRODUCTION

A higher rate of subtherapeutic psychotropic drug concentrations was recently found in HIV-infected versus HIV-negative patients. In this study, we sought to investigate if this trend could also apply to antiepileptic drugs.

METHODS

Overall, 700 HIV-infected patients were screened during the first 2 years after the introduction of our outpatient polytherapy management service (Gestione Ambulatoriale Politerapie [GAP]) in the search for subjects with antiepileptic drug trough concentration assessments. The distribution of such concentrations was compared with that in HIV-negative patients monitored over the same period.

RESULTS

The search identified 97 HIV-infected patients concomitantly receiving antiretroviral and antiepileptic drugs, for a total of 310 drug measurements. Overall, 30%, 64% and 6%, versus 28%, 65% and 7%, of the antiepileptic concentrations measured in HIV-infected versus HIV-negative patients (1090 patients, for a total of 3488 antiepileptic concentrations measured) were below, within, or above the therapeutic targets, respectively. The antiepileptic drug valproate was associated with the highest risk of subtherapeutic drug concentrations, with 57% and 46% of determinations below the therapeutic range in HIV-positive and HIV-negative patients, respectively. Remarkably, the concentrations of valproate were significantly lower in HIV-infected versus HIV-negative patients (47.9 ± 21.2 versus 53.9 ± 21.6 mg/L; p < 0.05).

CONCLUSION

In our retrospective study, most HIV-infected patients had antiepileptic drug concentrations falling within the therapeutic targets, with the exception of valproate, which was associated with a higher rate of subtherapeutic concentrations compared with other antiepileptic drugs.

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.

The challenge of HIV treatment in an era of polypharmacy

INTRODUCTION

The availability of potent antiretroviral therapy has transformed HIV infection into a chronic disease such that people living with HIV (PLWH) have a near normal life expectancy. However, there are continuing challenges in managing HIV infection, particularly in older patients, who often experience age-related comorbidities resulting in complex polypharmacy and an increased risk for drug-drug interactions. Furthermore, age-related physiological changes may affect the pharmacokinetics and pharmacodynamics of both antiretrovirals and comedications thereby predisposing elderly to adverse drug reactions. This review provides an overview of the therapeutic challenges when treating elderly PLWH (i.e. >65 years). Particular emphasis is placed on drug-drug interactions and other common prescribing issues (i.e. inappropriate drug use, prescribing cascade, drug-disease interaction) encountered in elderly PLWH.

DISCUSSION

Prescribing issues are common in elderly PLWH due to the presence of age-related comorbidities, organ dysfunction and physiological changes leading to a higher risk for drug-drug interactions, drugs dosage errors and inappropriate drug use.

CONCLUSIONS

The high prevalence of prescribing issues in elderly PLWH highlights the need for ongoing education on prescribing principles and the optimal management of individual patients. The knowledge of adverse health outcomes associated with polypharmacy and inappropriate prescribing should ensure that there are interventions to prevent harm including medication reconciliation, medication review and medication prioritization according to the risks/benefits for each patient.

Escitalopram population pharmacokinetics in people living with human immunodeficiency virus and in the psychiatric population: Drug-drug interactions and probability of target attainment

AIMS

The aims of this study were to characterize escitalopram pharmacokinetic profile, to identify factors influencing drug exposure, notably drug-drug interactions with antiretrovirals, and to simulate expected exposure under standard dosage regimen.

METHODS

A population pharmacokinetic analysis was performed using NONMEM. A total of 159 plasma concentration measurements were obtained from 39 human immunodeficiency virus (HIV)-infected and 71 uninfected psychiatric patients. The influence of age, weight, sex, HIV and psychiatric cohorts, racemic citalopram treatment, and comedications on oral clearance was examined. Simulations served to calculate the percentage of patients expected to be under- or over-exposed, considering established therapeutic targets (15-80 ng/mL).

RESULTS

A 1-compartment model with first-order absorption and elimination described the data adequately. The average escitalopram clearance and volume of distribution were 23.1 L/h (interindividual variability 51%), and 920 L, respectively. Escitalopram disposition did not differ between HIV-infected and uninfected patients, and was not affected by antiretroviral treatments. Coadministration of at least 1 proton-pump inhibitor (CYP2C19 inhibitor) modestly influenced escitalopram elimination (clearance decreased by 19%), with limited clinical relevance. Model-based simulations showed that, under a standard regimen of 10 mg once daily, a significant proportion of patients (56%) might be under-exposed.

CONCLUSION

The variability in escitalopram disposition is large and poorly explained by demographic, clinical and environmental covariates, thus suggesting a role for dosage individualization based on therapeutic drug monitoring in case of poor clinical response. Escitalopram disposition is modestly impacted by comedications and therefore no a priori dosage adjustments are needed in patients receiving antiretroviral treatments, including boosted regimens.