The association between antiepileptic drug and HMG-CoA reductase inhibitor co-medication and cholesterol management in patients with epilepsy

Significance of Statin-Associated Muscle Symptoms and Its Impact on Patients Adherence and Outcomes

ABSTRACT

Statin-associated muscle symptoms (SAMS) are one of the most common side effects of statins. This study aimed to explore the significance of SAMS among statin users by comparing statin users with a control group. To achieve our aims, a propensity score matching the retrospective cohort study was conducted in a single center tertiary hospital. The statin muscle symptoms were assessed using the Proposed Statin Myalgia Index Score, whereas the patient's adherence to medications was evaluated using the Morisky Medication Adherence Scale-8. We included 743 patients in our study; of them, 64.9% were on statin, whereas the rest were controls (35.1%). After propensity score matching, patients on statin had significantly higher rates of SAMS (5.0%) compared with control (1.6%) (AOR = 3.209; 95% CI: 1.020-10.091). However, there was no significant difference between statin users and controls in medications nonadherence ( P -value = 0.820). Our analysis among statins users revealed that moderate-intensity (2.671; 95% CI: 1.691-3.310) and high-intensity (3.552; 95% CI: 2.190-4.129) statin therapy was significantly associated with SAMS. In addition, autoimmune diseases were significantly associated with SAMS occurrence (AOR = 32.301; 95% CI: 1.785-584.374). Also, patients on PPIs had significantly less occurrence of SAMS (AOR = 0.145; 95% CI: 0.044-0.483), whereas patients on antiepileptic drugs had significantly higher SAMS occurrence (AOR = 72.337; 95% CI: 2.649-1975.201). Regarding MACE among statin users, there was no significant difference in the 1-year or 5-year MACE rate between statin users and controls. Our study suggests that SAMS are significant among statin users and must be addressed by health care providers to ensure that patients are still adherent to their medications and hence protected against cardiac events.

Enzyme-inducing antiseizure medication utilization in patients with epilepsy and vascular risk factors

OBJECTIVES

Several lines of evidence have suggested that exposure to enzyme-inducing antiseizure medications (EIASMs) may result in the subsequent development of hyperlipidemia, a well-known risk factor for vascular disease. This may be an issue of concern particularly in the context of additional comorbid vascular risk factors. We therefore aimed to investigate trends of and associations with the use of these medications among adult patients with epilepsy.

METHODS

The cross-sectional Medical Expenditure Panel Survey (MEPS) was interrogated to ascertain the prevalence of use of EIASMs by noninstitutionalized adult patients with epilepsy in the United States between the years 2004 and 2015. Any patient prescribed carbamazepine, phenytoin, phenobarbital, or primidone within a given year was defined as having been prescribed an EIASM. Trends over three-year epochs were evaluated with univariate logistic regression, while associations with demographic factors, vascular risk factors, and vascular disease were evaluated using a chi-square test corrected for survey design as well as multivariate logistic regression.

RESULTS

A total of 2281 (unweighted) patients were identified, representing 1,781,237 individuals. Between 2004 and 2015, 45.9% (95% confidence interval [CI]: 42.4%-49.4%) were prescribed EIASMs. Approximately one-quarter of patients aged 65 years and above used EIASMs compared with 18.5% of younger patients (odds ratio [OR]: 1.83, 95% CI = 1.27-2.65). Female patients (OR = 0.61, 95% CI = 0.47-0.79) and those with heart disease (OR: 0.63, 95% CI = 0.45-0.89) were significantly less likely to be prescribed EIASMs. Among those prescribed EIASMs, 38.9% had hypertension, 12.2% had diabetes, 61.6% were overweight or obese, 17.3% heart disease, 17.2% had a history of a cerebrovascular event, and 28.5% had diagnosed hyperlipidemia. Nonetheless, between 2004-2006 and 2013-2015, the odds of EIASM prescription decreased significantly (OR: 0.39, 95% CI: 0.28-0.55).

CONCLUSIONS

A substantial proportion of patients with comorbid vascular disease or vascular risk factors (e.g., hypertension and older age) is prescribed EIASMs. This could potentially increase patients' risk for subsequent negative outcomes such as cardiovascular or cerebrovascular disease. Though utilization of these medications has decreased, further efforts toward increasing use of newer antiseizure medications (ASMs) that are not associated with similar risks may be warranted.

Management of antiepileptic drug-induced nutrition-related adverse effects

Although antiepileptic drugs (AEDs) are mainstay of the treatment of epilepsy, they are associated with significant adverse effects. The present study reviews the adverse effects of AEDs on some of the nutrition-related issues, including bone health, body weight, glucose and lipid metabolism, vitamin homeostasis, antioxidant defense system, and pregnancy. This paper also provides some nutritional recommendations for people with epilepsy. Patients with epilepsy should be regularly evaluated with regard to their nutrition status and any possible nutritional problems. Daily intake of adequate amounts of all nutrients from various sources should be encouraged, especially for vulnerable groups such as children, adolescents, elderly, and pregnant women. When necessary, preventative or therapeutic supplementation with appropriate micronutrients could be helpful. Graphical abstract.

Statins: Pharmacokinetics, Pharmacodynamics and Cost-Effectiveness Analysis

Cardiovascular diseases secondary to atherosclerosis are the primary causes of early death and disability worldwide and dyslipidaemia represents one of the most important modifiable risk factors. Among lipid abnormalities that define it, low-density lipoprotein cholesterol (LDL-C) is the primary target of therapy, since multiple randomized controlled trials have shown the positive impact of its reduction on atherosclerosis development. For their ability to lower LDL-C levels, statins are the most studied drugs in cardiovascular disease prevention, of proven utility in slowing the progression or even determining regression of atherosclerosis. In addition, they have ancillary proprieties, with positive effects on the mechanisms involved in the development of atherosclerosis and cardiovascular morbidity and mortality, the so-called "pleiotropic mechanisms". Although sharing the same mechanism of action, the different chemical and pharmacological characteristics of each kind of statins affect their absorption, bioavailability, plasma protein binding properties, excretion and solubility. In this overview, we analysed pharmacokinetic and pharmacodynamic mechanisms of this class of drugs, specifying the differences among the molecules, along with the economic aspects. Detailed knowledge of characteristics and differences of each kind of available statin could help the physician in the correct choice, based also on patient's clinical profile, of this essential tool with a demonstrated high cost-effectiveness both in primary than in the secondary prevention of cardiovascular disease.

Discontinuation of carbamazepine due to concerns of long-term consequences of enzyme induction

Objective

Treatment with carbamazepine (CBZ), a potent enzyme inducer, is known to affect the lipid profile, steroid, and vitamin D metabolism. Consequently, it has been postulated that patients on CBZ should be switched to noninducing antiepileptic drugs (AEDs). However, little is known about the seizure outcome following a CBZ switch in seizure‐free patients. We aimed to address this issue using a controlled observational study design.

Methods

Fifty‐eight patients taking CBZ for focal epilepsy were assessed for discontinuing CBZ treatment due to concerns of long‐term adverse‐effects; 34 discontinued its therapy and 24 continued with CBZ. Six‐month seizure freedom was the primary end point. Furthermore, serum samples (total cholesterol (TC), low‐density lipoprotein (LDL), high‐density lipoprotein (HDL), triglycerides, sex hormone–binding globulin (SHBG), free testosterone, and 25‐hydroxyvitamin D levels from before and at least 3 months after discontinuation or continuation were obtained from all patients.

Results

Seizure‐free patients had a 5‐fold elevated odds of seizure recurrence if CBZ was discontinued (95% confidence interval [CI 0.51–49.3; p = 0.17). A significant decrease in serum levels of TC, LDL, HDL, and SHBG as well as a significant increase in that of free testosterone were found in the discontinuation group compared with those who continued CBZ. Nonsignificant changes in triglycerides and vitamin D levels were detected.

Significance

Discontinuation of CBZ in seizure‐free patients seems to carry a moderate, but legitimate, risk of relapse. Conversely, our results indicate that CBZ might have unfavorable effects on serum levels of TC, LDL, HDL, SHBG, and free testosterone.

Use of antiepileptic drugs and lipid-lowering agents in the United States

INTRODUCTION

The extent to which enzyme-inducing antiepileptic drugs (EIAEDs) are used as first-line treatment in the United States remains unknown. Studies suggest that EIAEDs produce elevation of serum lipids, which could require additional treatment. We assessed the current use of EIAED in monotherapy for epilepsy in the U.S., as well as the correlation between the use of EIAEDs and subsequent new prescriptions for HMG-CoA reductase inhibitors ("statins") for hyperlipidemia.

METHODS

We queried the MarketScan databases between July 2009 and January 2013, covering 66 million patients with commercial or supplemental Medicare insurance. We identified individuals who had a diagnosis of seizures, continuous enrollment in the database from 6months prior to 24 months after the epilepsy diagnosis, no utilization of an AED or a statin prior to that diagnosis, and at least 1 new AED prescription. We tabulated the fraction of subjects who were prescribed EIAEDs (phenytoin, carbamazepine, or barbiturates) and those prescribed all other AEDs. Rates of new statin prescription between 1 and 24months after AED prescription were assessed among the two groups, restricted to those with no prior history of vascular disease who had lipid serology obtained subsequent to the new AED prescription.

RESULTS

Of the 11,893 patients with newly treated epilepsy, 2425 (20.4%) were started on an EIAED, and 9468 (79.6%) were started on a noninducing AED. There was a consistent and significant trend for EIAEDs to be increasingly prescribed with increasing age (p<0.0001). Among patients meeting the criteria, 66 (13.3%) of 496 EIAED-treated patients and 178 (9.2%) of 1930 noninducing AED patients were newly prescribed a statin (p<0.007). This difference remained significant after accounting for age and gender (p=0.015). A patient who was started on an EIAED was 46% more likely to be subsequently prescribed a statin than a patient who was started on a noninducing AED (95% CI=1.08-1.98).

CONCLUSIONS

Enzyme-inducing antiepileptic drug prescription for epilepsy appears to increase with increasing age in the U.S. despite the absence of a cogent rationale for this practice, suggesting a failure to appreciate the complications of EIAED therapy among U.S. physicians. Statins were more often prescribed to those newly treated with EIAEDs compared with those given noninducing AEDs. These preliminary data provide further evidence suggesting that EIAEDs elevate lipids in a clinically meaningful manner.

Pharmacodynamic potentiation of antiepileptic drugs' effects by some HMG-CoA reductase inhibitors against audiogenic seizures in DBA/2 mice

It is known that the 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) are effective in both the primary and the secondary prevention of ischemic heart disease. Increasing evidence indicates that statins have protective effects in several neurological diseases including stroke, cerebral ischemia, Parkinson disease, multiple sclerosis, traumatic brain injury and epilepsy. The aim of the present research was to evaluate the effects of some HMG-CoA reductase inhibitors (i.e. lovastatin, simvastatin, atorvastatin, fluvastatin and pravastatin) commonly used for the treatment of hypercholesterolemia in the DBA/2 mice, an animal model of generalized tonic-clonic seizures. Furthermore, the co-administration of these compounds with some antiepileptic drugs (AEDs; i.e. carbamazepine, diazepam, felbamate, gabapentin, lamotrigine, levetiracetam, oxcarbazepine, phenobarbital, phenytoin, topiramate and valproate) was studied in order to identify possible positive pharmacological interactions. Simvastatin only was active against both the tonic and clonic phase of audiogenic seizures, whereas the other statins tested were only partially effective against the tonic phase with the following order of potency: lovastatin>fluvastatin>atorvastatin; pravastatin was completely ineffective up to the dose of 150mg/kg. The co-administration of ineffective doses of all statins with AEDs generally increased the potency of the latter reducing their ED50 values. In particular, simvastatin was the most active in potentiating the activity of AEDs and the combinations of statins with carbamazepine, diazepam, felbamate, lamotrigine, topiramate and valproate were the most favorable, whereas, the co-administrations with the other AEDs studied was in most cases neutral. The increase in potency was generally associated with an enhancement of motor impairment (TD50); however, the therapeutic index (TD50/ED50) of combined treatment of AEDs with statins was predominantly more favorable than control. Statins administration did not significantly affect the total plasma but, in some cases, it increased the free plasma levels and the brain concentrations of some of the AEDs studied (i.e. carbamazepine, diazepam, phenytoin and valproate); however, these alterations where not statistically significant. Therefore, with the exception of the latter compounds, we might exclude pharmacokinetic interactions and conclude that for the most of AEDs, potentiation was of pharmacodynamic nature. In conclusion, simvastatin, fluvastatin, lovastatin and atorvastatin showed an additive anticonvulsant effect when co-administered with some AEDs, most notably carbamazepine, diazepam, felbamate, lamotrigine, topiramate and valproate, implicating a possible therapeutic relevance of such drug combinations. The present results suggest that statins, besides the beneficial cardiovascular effects, might be able to affect brain areas, which might participate in the regulation of seizure susceptibility.

Statin medication in patients treated with antiepileptic drugs in Norway

PURPOSE

The lipid-lowering response of statins metabolized by cytochrome P450 3A4 (CYP3A4) has previously been shown to be diminished by concurrent use of enzyme-inducing antiepileptic drugs (EIAEDs). The aim of this study was to compare statin prescription in patients receiving EIAEDs versus non-enzyme-inducing antiepileptic drugs (NEIAEDs), before and after introduction of prescribing restrictions for statins in Norway.

METHODS

The Norwegian Prescription Database was used to extract data on patients using antiepileptic drugs and statins during 2004 and 2008. Statin type and dose used were compared between patients treated with at least one EIAED (i.e., carbamazepine, phenobarbital, phenytoin, primidone) and those receiving NEIAEDs only (i.e., all other antiepileptic drugs).

RESULTS

The number of included patients co-medicated with statins and AEDs was 4855 in 2004 and 9880 in 2008. Among these patients, 2827 and 3160, respectively, were treated with EIAEDs. The CYP3A4 statins (i.e., simvastatin, atorvastatin and lovastatin) accounted for 85% of all statins in 2004, increasing to 93% in 2008. There was no significant difference in the likelihood of being prescribed a CYP3A4 statin versus a non-CYP3A4 statin among patients receiving EIAEDs and NEIAEDs. The average daily dose of individual CYP3A4 statins was not different between the AED groups.

CONCLUSIONS

The present study shows that the interaction risk between CYP3A4-metabolized statins and EIAEDs is largely overlooked in Norwegian clinical practice. To avoid therapeutic failure of statin treatment in patients using AEDs, implementation of strategies for systematic management of drug interactions is warranted.