When Coadministration Cannot Be Avoided: Real World Experience of Direct Acting Antivirals for the Treatment of Hepatitis C Virus Infection in Patients on First Generation Anticonvulsants

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.

Hepatitis C virus treatment with glecaprevir and pibrentasvir in patients co-prescribed carbamazepine: Three case reports

BACKGROUND

Highly effective and well-tolerated direct-acting antiviral (DAA) therapies have revolutionised the management of hepatitis C virus (HCV); however, niche populations face treatment barriers. DAAs co-prescribed with several first-generation anti-epileptic drugs (AEDs) are contraindicated due to drug-drug interactions. A common example is carbamazepine whereby steady-state carbamazepine reduces the maximum concentration and area under the curve of velpatasvir, glecaprevir and pibrentasvir due to potent cytochrome P450 (CYP) 3A4 induction. Carbamazepine also induces P-glycoprotein which reduces glecaprevir and pibrentasvir’s area under curve to infinite time. Sofosbuvir-velpatasvir and glecaprevir-pibrentasvir are contraindicated in patients who are co-prescribed carbamazepine due to the risk of reduced DAA therapeutic effect and consequently, virological treatment failure. This presents a challenge for patients in whom carbamazepine substitution is medically unfeasible, impractical or unacceptable. However, the properties of current generation DAA therapies, including high-potency non-structural protein 5A inhibitory effect, may be sufficient to overcome reduced bioavailability arising from carbamazepine related CYP 3A4 and P-glycoprotein induction.

CASE SUMMARY

We present a case series of three patients with non-cirrhotic, treatment-naïve, genotype 1a, 1b, and 3a HCV who were treated with a 12 wk course of glecaprevir-pibrentasvir, while co-prescribed carbamazepine for seizure disorders. Glecaprevir-pibrentasvir combination therapy was chosen due to its potent in vitro activity and low barrier to pan-genotypic resistance associated variants. DAA therapy was dose-separated from carbamazepine to maximise time to peak concentration, and taken with meals to improve absorption. Sustained virological response at 12 wk was achieved in each patient with no adverse outcomes.

CONCLUSION

DAA therapies, including glecaprevir-pibrentasvir, warrant consideration as a therapeutic agent in people with HCV who are co-prescribed carbamazepine, particularly if AED substitution is not feasible.

Challenges of Treating an Acute Hepatitis C Virus Infection With Concurrent Seizure Treatment in a Free Clinic

Currently, there is limited data evaluating the coadministration of first-generation anticonvulsants for epilepsy treatment and direct-acting antivirals (DAAs) for the treatment of hepatitis C virus (HCV) infection. There is a potential risk of suboptimal DAA serum concentrations that could potentially lead to HCV treatment failure. In this report, we describe the case of an uninsured, non-Hispanic Black male in his mid-40s with a history of generalized epilepsy that was managed with phenytoin 100mg twice a day and divalproex 500mg extended-release once daily. He was diagnosed with an acute hepatitis C viral infection with a genotype of 1a. Due to the viral genotype, treatment naivety, and lack of cirrhosis, the recommended treatment is to start glecaprevir/pibrentasvir, but the concomitant use of phenytoin and glecaprevir/pibrentasvir is not recommended due to a drug-drug interaction that could lead to subtherapeutic DAA levels and possible treatment failure. Through shared decision-making and close follow-up, we slowly weaned the patient off phenytoin, replaced it with levetiracetam, and started glecaprevir/pibrentasvir. We successfully eradicated the patient’s HCV infection, and no breakthrough seizures were reported. Although an unprecedented case and with the limited data evaluating the coadministration of DAAs and treatment of acute HCV infection, we were able to successfully treat and achieve full remission of the HCV infection. By virtue of this case report, we hope to encourage others to report similar cases and spread awareness regarding the difficulties in management.