According to the World Health Organization, up to 70% of people with epilepsy could become seizure-free with the use of medications. Seizure medications can increase or decrease the levels of other substances in your blood.¹
If you’re about to start any new medication or have problems with your current medication, talk to your doctor about potential drug interactions. If you’ve been prescribed medication for epilepsy, you don’t want to end up with unwanted drug interactions.
It’s important to be transparent with your doctor about all medications you’re taking, including OTC medicines.
The drugs outlined below should be used with caution. Some individuals can take other medications alongside their antiepileptic drugs without any negative effects, while others experience drastic effects.
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Diphenhydramine and other antihistamines used for treating allergies can increase seizure susceptibility, with the increased risk extending beyond the course of treatment.
Pseudoephedrine, phenylephrine, and dextromethorphan are all used to alleviate cold symptoms, particularly congestion. These drugs can potentially lower the threshold for seizure occurrence.
Antibiotics have shown some risks of increasing seizure frequency, including penicillin, cephalosporins, carbapenem, and quinolones. While, for the most part, this is a rare occurrence, the best option is to avoid using these medications unless necessary.²
Additionally, talk to your doctor about all the potential side effects and interactions these drugs may have with your seizure medication.
Antipsychotics and their interactions with antiepileptics have not been widely investigated. However, early research suggests that their interactions may impact the efficacy and toxicity of both drugs. For example, clozapine should be avoided if you are already taking carbamazepine because of the adverse effects these drugs may have on the blood.
Some antidepressants have a low risk of affecting the seizure threshold. Amitriptyline and clomipramine, in particular, are a higher risk when compared with other antidepressants. It is recommended to start with a low antidepressant dose initially and gradually increase this to a therapeutic dose.
Opioids taken at a high concentration have also been found to increase seizure frequency. This effect varies between individuals and is based on the dosage amount.
Birth control can be hormonal or non-hormonal. One study identified that the use of hormonal contraceptives might increase seizure frequency. Many seizure medications induce the metabolism of your birth control pills, making them less effective.³
You may want to explore other contraceptive options to reduce the potential for unplanned pregnancies.
This interaction is reciprocal, as taking birth control can also affect the efficacy of your seizure medication. For example, lamotrigine is a common antiepileptic medication.
One study investigated taking lamotrigine alongside a hormonal contraceptive, finding that after not taking the contraceptive, concentrations of lamotrigine increased by 84%. This highlights that birth control was drastically affecting the concentration of epilepsy medication, increasing the risk of seizures.⁴
The use of natural alternatives to medicine is on the rise. While this can be highly beneficial for some conditions, it’s important to remember that herbal supplements can still interact with other medications you’re taking.
Some herbal medicines have also been found to increase the frequency of seizures. For example, evening primrose oil is commonly used for conditions like diabetic neuropathy and attention deficit hyperactivity disorder (ADHD).
Some evidence has been found that it lowers the threshold for seizures. Ginkgo, ginseng, black cohosh, and ephedra have all been found to potentially increase the occurrence of seizures. Folic acid, a common dietary supplement, has been found to interact with the metabolism of epilepsy medication.⁵ ⁶
The interaction between herbal supplements and pharmaceutical drugs is more complex and unpredictable compared to interactions between different drugs. If you’re taking any herbal medicines, inform your doctor to ensure that this will not cause any complications or added risks for you.
Drugs aren’t the only factor to consider when treating your seizures. Sleep deprivation, stress, and alcohol consumption have all been found to increase seizure frequency.
Over-the-counter medication, dietary supplements, herbal medicines, and prescription medication all have the potential to interact reciprocally with your epilepsy medication. Many of these effects have not been investigated in depth, making it challenging to predict their exact effect on the frequency of your seizures or other effects they may have on your body.
Individual differences can also play a large role in how different substances affect the body. It is best to outline all the medications you are taking with your doctor to determine possible interactions and steps you can take to minimize any potentially harmful effects.
Epilepsy | World Health Organization
Medications which may lower seizure threshold | NPS Medicine Wise
What medications are safe to take with seizure medications if you have a respiratory bug? | Department of Neurology
Using antidepressants for depression in people with epilepsy | Specialist Pharmacy Service
Dextromethorphan and phenylephrine | Peace Health