Antidepressant-associated myoclonic status in a patient with symptomatic generalized epilepsy: does risk occur with therapeutic doses?

Antiepileptic drugs and serotonin syndrome- A systematic review of case series and case reports

Serotonin syndrome (SS) is a drug‑induced, potentially fatal, clinical syndrome resulting from drugs that have serotonergic properties. Several antiepileptic drugs (AEDs) are known to have serotonergic properties and it can be hypothesized that such AEDs can cause SS. This study aims to review the literature on SS in patients receiving AEDs. We performed a systematic review of Scopus and MEDLINE/PUBMED for case reports and case series of SS where patients had received at least one AED at the onset of symptoms. The cases published in the English literature between 1 January 1991 and 1 April 2021 were included. Initial search identified 1263 articles of which 63 (76 patients) were included in the final analysis. Most of the included cases (53 cases, 70%) have been published in the last 10 years. The mean age of the 76 patients was 40.6 ± 17.8 years, and 51% of cases were females. These patients had been exposed to a total of 8 different types of AEDs. Valproic acid was the most common drug (29, 38%), followed by lamotrigine (22, 29%), gabapentin (16, 21%), pregabalin (seven, 9%), topiramate (five, 7%) and carbamazepine (two, 3%). There has been one case each with phenytoin and oxcarbazepine. Seven (9%) patients received more than one AEDs. Most patients (67, 88%) also received other serotoninergic agents. Only nine (12%) patients were on AEDs alone. The most common clinical condition for using AEDs was psychiatric disorders (36 patients, 47.3%), followed by migraine (17, 22.4%), other painful conditions (15, 19.7%), epilepsy (7, 9.2%), and perioperative conditions (8, 10.5%). Death was reported in two patients. We suggest that AEDs, because of their serotonergic properties, may induce SS, especially in patients who are on another serotonergic agent.

Antidepressant use and risk of epilepsy and seizures in people aged 20 to 64 years: cohort study using a primary care database

BACKGROUND

Epilepsy is a serious condition which can profoundly affect an individual's life. While there is some evidence to suggest an association between antidepressant use and epilepsy and seizures it is conflicting and not conclusive. Antidepressant prescribing is rising in the UK so it is important to quantify absolute risks with individual antidepressants to enable shared decision making with patients. In this study we assess and quantify the association between antidepressant treatment and the risk of epilepsy and seizures in a large cohort of patients diagnosed with depression aged between 20 and 64 years.

METHODS

Data on 238,963 patients with a diagnosis of depression aged 20 to 64 from 687 UK practices were extracted from the QResearch primary care database. We used Cox's proportional hazards to analyse the time to the first recorded diagnosis of epilepsy/seizures, excluding patients with a prior history and estimated hazard ratios for antidepressant exposure adjusting for potential confounding variables.

RESULTS

In the first 5 years of follow-up, 878 (0.37 %) patients had a first diagnosis of epilepsy/seizures with the hazard ratio (HR) significantly increased (P < 0.01) for all antidepressant drug classes and for 8 of the 11 most commonly prescribed drugs. The highest risks (in the first 5 years) compared with no treatment were for trazodone (HR 5.41, 95 % confidence interval (CI) 3.05 to 9.61, number needed to harm (NNH) 65), lofepramine (HR 3.09, 95 % CI 1.73 to 5.50, NNH 138), venlafaxine (HR 2.84, 95 % CI 1.97 to 4.08, NNH 156) and combined antidepressant treatment (HR 2.73, 95 % CI 1.52 to 4.91, NNH 166).

CONCLUSIONS

Risk of epilepsy/seizures is significantly increased for all classes of antidepressant. There is a need for individual risk-benefit assessments in patients being considered for antidepressant treatment, especially those with ongoing mild depression or with additional risk factors. Residual confounding and indication bias may influence our results, so confirmation may be required from additional studies.

Nonconvulsive status epilepticus in the elderly associated with newer antidepressants used at therapeutic doses: A report of three cases

Classic antidepressants have been known to induce convulsive seizures and nonconvulsive status epilepticus (NCSE). On the other hand, many reports have emphasized the safety of novel antidepressants. However, we encountered three cases of NCSE in the elderly associated with the use of newer antidepressants at therapeutic doses. All three patients were male and were 73 years of age or older. One patient was recently diagnosed with temporal lobe epilepsy and treated with low-dose lamotrigine. In all patients, newer antidepressants were initiated because of depressive symptoms. After titrating to therapeutic doses (paroxetine 20 mg/day, sertraline 50 mg/day, and combination of sertraline 50 mg/day and mirtazapine 30 mg/day in one patient each), impaired consciousness appeared. Electroencephalography (EEG) showed generalized slow waves with intermittent spike-slow-wave complexes. Intravenous injection of antiepileptic drugs improved EEG findings and clinical symptoms. After discontinuance of the abovementioned antidepressants, NCSE did not recur in any of patients. These reports raise the question of whether the newer antidepressants, like classic antidepressants, might also induce NCSE in the elderly, even when used at therapeutic doses. Physicians should consider monitoring for possible NCSE when using newer antidepressants in patients who may have low drug tolerability. Active continuous video-EEG monitoring is essential when behavioral and psychological symptoms or change in consciousness level is suspected.

Seizures during antidepressant treatment in psychiatric inpatients--results from the transnational pharmacovigilance project "Arzneimittelsicherheit in der Psychiatrie" (AMSP) 1993-2008

RATIONALE

There is little clinical data available about seizure rates in psychiatric inpatients, and there are no studies with reference data to the frequencies of antidepressant (AD) use for this important clinical population.

OBJECTIVE

This study investigates seizure rates during AD treatment in psychiatric inpatient settings, drawn from the transnational pharmacovigilance programme Arzneimittelsicherheit in der Psychiatrie (AMSP) in relation to the known frequencies of ADs used in the participating clinics. Comparisons are made to former publications and their limitations.

RESULTS

Seventy-seven cases were identified with grand mal seizures (GMS) during AD treatment between 1993 and 2008, with a total number of 142,090 inpatients under surveillance treated with ADs in the participating hospitals. The calculated overall rate of reported seizures of patients during AD treatment in this collective is 0.05 % for ADs imputed alone or in combination with other psychotropic drug groups and 0.02 % when only ADs were given and held responsible for GMS. The patients receiving tri- or tetracyclic ADs (TCAs) had a 2-fold risk to develop a seizure as compared to the overall average rate in this sample. In 11 cases, there was only one AD imputed--the majority of these cases (9/11) were TCA. Monotherapy with selective serotonin reuptake inhibitors (SSRI) or dual serotonin and noradrenaline reuptake inhibitors (SNRI) were never imputed alone in this sample.

CONCLUSIONS

The results of the study favour the assumption that SSRIs, noradrenergic and specific serotonergic antidepressants (NaSSA) and dual SNRI might be more appropriate than TCAs for the treatment of psychiatric patients with an enhanced seizure risk.