Can Remeron (Mirtazapine) Cause Seizures?
Mirtazapine has a very low potential for inducing seizures, but seizures can occur, particularly in predisposed patients or at higher doses. The FDA label explicitly lists seizures as a possible side effect, and patients with a history of seizures should be monitored carefully 1.
Seizure Risk Profile
The seizure risk with mirtazapine is extremely low (0.0%-0.4%) in non-predisposed patients, similar to the baseline incidence of first seizures in the general population (0.07%-0.09%). 2 This makes mirtazapine one of the safer antidepressants regarding seizure risk, with clinical trial and postmarketing data confirming a "very low potential for inducing seizures" 3.
Key Safety Data:
- Mirtazapine appears safer than many other antidepressants for seizure risk - it has lower seizure potential than tricyclic antidepressants (0.4%-2% risk) and is considered among the safer newer antidepressants 2, 3
- The drug is notably safe in overdose - in 10 patients taking overdoses up to 315mg, excessive somnolence was the only symptom noted, with no seizures reported 3
- In a series of 33 isolated mirtazapine overdoses (mean 343mg, range 15-1500mg), no seizures were documented 4
When Seizures Can Occur
Despite the overall low risk, seizures have been documented in specific circumstances:
Dose-Related Risk:
- A case report documented focal motor seizures and status epilepticus when a patient increased mirtazapine from 30mg to 45mg daily 5
- The patient experienced clonic seizures of the right lower limb at 45mg, which progressed to focal clonic status epilepticus with further dose increases 5
- Seizures resolved completely after discontinuing mirtazapine 5
Combination Therapy Risk:
- Status epilepticus occurred in a patient receiving both olanzapine and mirtazapine 60mg, though the primary culprit was likely olanzapine 6
- This highlights that concomitant medications may increase seizure risk 6
Clinical Recommendations
Patient Screening:
Before prescribing mirtazapine, screen for seizure predisposition including: 1, 2
- Personal history of seizures or convulsions
- Family history of seizure disorders
- Conditions that lower seizure threshold (brain injury, alcohol withdrawal, metabolic disturbances)
- Concurrent medications that lower seizure threshold
Prescribing Guidance:
- Standard dosing (15-30mg daily) carries minimal seizure risk in non-predisposed patients 7, 3
- Exercise caution when increasing to the maximum 45mg dose, particularly in patients with any seizure risk factors 1, 5
- Avoid combining with other medications that lower seizure threshold 8, 6
Monitoring:
If seizures occur during mirtazapine therapy: 1, 5
- Discontinue mirtazapine immediately
- Seizure activity typically resolves after drug discontinuation
- Consider alternative antidepressants with even lower seizure potential (SSRIs like sertraline)
Important Caveats
The FDA label specifically warns that patients should inform their healthcare provider if they "have seizures" before starting mirtazapine 1. While the overall risk is very low, mirtazapine is not completely devoid of seizure risk, particularly at higher doses or in vulnerable populations 8, 5. The drug's excellent safety profile in overdose and low baseline seizure incidence make it a reasonable choice for most patients, but individualized risk assessment remains essential 2, 3.