Indapamide enhances the protective action of carbamazepine, phenobarbital, and valproate against maximal electroshock-induced seizures in mice

Interactions of antiepileptic drugs with drugs approved for the treatment of indications other than epilepsy

Introduction: Comorbidities of epilepsy may significantly interfere with its treatment as diseases in the general population are also encountered in epilepsy patients and some of them even more frequently (for instance, depression, anxiety, or heart disease). Obviously, some drugs approved for other than epilepsy indications can modify the anticonvulsant activity of antiepileptics. Areas covered: This review highlights the drug-drug interactions between antiepileptics and aminophylline, some antidepressant, antiarrhythmic (class I-IV), selected antihypertensive drugs and non-barbiturate injectable anesthetics (ketamine, propofol, etomidate, and alphaxalone). The data were reviewed mainly from experimental models of seizures. Whenever possible, clinical data were provided. PUBMED data base was the main search source.Expert opinion: Aminophylline generally reduced the protective activity of antiepileptics, which, to a certain degree, was consistent with scarce clinical data on methylxanthine derivatives and worse seizure control. The only antiarrhythmic with this profile of action was mexiletine when co-administered with VPA. Among antidepressants and non-barbiturate injectable anesthetics, trazodone, mianserin and etomidate or alphaxalone, respectively, negatively affected the anticonvulsant action of some antiepileptic drugs. Clinical data indicate that only amoxapine, bupropion, clomipramine and maprotiline should be used with caution. Possibly, drugs reducing the anticonvulsant potential of antiepileptics should be avoided in epilepsy patients.

Aging-Exacerbated Acute Axon and Myelin Injury Is Associated with Microglia-Derived Reactive Oxygen Species and Is Alleviated by the Generic Medication Indapamide

Age is a critical risk factor for many neurologic conditions, including progressive multiple sclerosis. Yet the mechanisms underlying the relationship are unknown. Using lysolecithin-induced demyelinating injury to the mouse spinal cord, we characterized the acute lesion and investigated the mechanisms of increased myelin and axon damage with age. We report exacerbated myelin and axon loss in middle-aged (8-10 months of age) compared with young (6 weeks of age) female C57BL/6 mice by 1-3 d of lesion evolution in the white matter. Transcriptomic analysis linked elevated injury to increased expression of Cybb, the gene encoding the catalytic subunit of NADPH oxidase gp91phox. Immunohistochemistry in male and female Cx₃cr1 ^CreER/+ :Rosa26 ^tdTom/+ mice for gp91phox revealed that the upregulation in middle-aged animals occurred primarily in microglia and not infiltrated monocyte-derived macrophages. Activated NADPH oxidase generates reactive oxygen species and elevated oxidative damage was corroborated by higher malondialdehyde immunoreactivity in lesions from middle-aged compared with young mice. From a previously conducted screen for generic drugs with antioxidant properties, we selected the antihypertensive CNS-penetrant medication indapamide for investigation. We report that indapamide reduced superoxide derived from microglia cultures and that treatment of middle-aged mice with indapamide was associated with a decrease in age-exacerbated lipid peroxidation, demyelination and axon loss. In summary, age-exacerbated acute injury following lysolecithin administration is mediated in part by microglia NADPH oxidase activation, and this is alleviated by the CNS-penetrant antioxidant, indapamide.SIGNIFICANCE STATEMENT Age is associated with an increased risk for the development of several neurologic conditions including progressive multiple sclerosis, which is represented by substantial microglia activation. We demonstrate that in the lysolecithin demyelination model in young and middle-aged mice, the latter group developed greater acute axonal and myelin loss attributed to elevated oxidative stress through NADPH oxidase in lineage-traced microglia. We thus used a CNS-penetrant generic medication used in hypertension, indapamide, as we found it to have antioxidant properties in a previous drug screen. Following lysolecithin demyelination in middle-aged mice, indapamide treatment was associated with decreased oxidative stress and axon/myelin loss. We propose indapamide as a potential adjunctive therapy in aging-associated neurodegenerative conditions such as Alzheimer's disease and progressive multiple sclerosis.

Drug treatments in patients with cardiac diseases and epilepsy

OBJECTIVE

Comorbidity between epilepsy and heart diseases is frequent.

METHODS

All drugs classified within the group of drugs for cardiovascular system according to the Anatomical Therapeutic Chemical (ATC) classification system were reviewed for their effects on seizures or epilepsy.

RESULTS

Several agents showed antiseizure properties in animal models of seizures and/or in patients with epilepsy and only few were proconvulsant. Drugs with anticonvulsant effects include mecamylamine and guanfacine (antihypertensive drugs), indapamide, amiloride, furosemide and bumetanide (diuretics), fasudil (peripheral vasodilator), bioflavonoids (vasoprotective drug), propranolol (beta blocking agent), isradipine, nimodipine, verapamil and diltiazem (calcium channel blockers: CCBs), fosinopril and zofenopril (agents acting on the renin-angiotensin system), several statins, and fenofibrate (lipid-modifying agents). Drugs with proconvulsant properties in experimental models or in patients include reserpine, buflomedil, naftidrofuryl, and clonidine and propranolol at high doses. Drug-drug interactions (DDI) between antiseizure medications (ASMs) and drugs for cardiovascular system were also searched in two leading publicly accessible drug compendia. The most important DDIs occur between enzyme-inducing (EI) ASMs and ivabradine, ranolazine, macitenan and between EI-ASMs and the CCBs felodipine, nicardipine, nisoldipine, and verapamil. Simvastatin and atorvastatin are the lipid-modifying agents with more DDIs with EI-ASMs. Several pharmacodynamic interactions have been also documented.

DISCUSSION AND CONCLUSIONS

Available data show that the treatment of patients with epilepsy and vascular comorbidities is challenging and requires the appropriate knowledge of pharmacological properties of drugs and drug interactions.

Interaction of pregabalin with carbamazepine in the mouse maximal electroshock-induced seizure model: a type I isobolographic analysis for non-parallel dose-response relationship curves

PURPOSE

To characterize the anticonvulsant effects of pregabalin (PGB - a third-generation antiepileptic drug) in combination with carbamazepine (CBZ - a classical antiepileptic drug) in the mouse maximal electroshock (MES)-induced seizure model by using the type I isobolographic analysis for non-parallel dose-response relationship curves (DRRCs).

MATERIAL/METHODS

Tonic hind limb extension (seizure activity) was evoked in adult male albino Swiss mice by a current (sine-wave, 25mA, 500V, 50Hz, 0.2s stimulus duration) delivered via auricular electrodes. Potential adverse-effect profiles of interaction of PGB with CBZ at the fixed-ratio of 1:1 in the MES test with respect to motor performance, long-term memory, skeletal muscular strength and antinociceptive activity were measured along with total brain CBZ concentrations.

RESULTS

In the mouse MES model, PGB administered singly had its DRRC non-parallel to that for CBZ. With type I isobolographic analysis for non-parallel DRRCs, the combination of PGB with CBZ at the fixed-ratio of 1:1 exerted additive interaction. In the combination, neither motor coordination, long-term memory nor muscular strength were affected. PGB administered alone and in combination with CBZ exerted antinociceptive effects, whereas CBZ administered alone produced no antinociceptive activity in mice subjected to the acute thermal pain model. Pharmacokinetic estimation of total brain antiepileptic drug concentrations revealed that PGB had no impact on total brain concentrations of CBZ in experimental animals.

CONCLUSIONS

In conclusion, the additive interaction between PGB and CBZ is worthy of consideration while extrapolating the results from this study to clinical settings.