Anti-Seizure Medication Side-Effects and Interactions

All medication, including Anti-seizure medication ASMs (also known as Anti-epileptic drugs AEDs), can potentially cause side effects. These vary from medication to medication and from person to person. When it comes to ASMs, any side effects are generally more noticeable when it is being taken for the first time or when the dose is increased. How long the side effects last also depends on the person. Some people won’t experience ASM side effects at all.

Generally doctors introduce ASMs slowly and gradually increase dosage levels over days or weeks, until you reach the desired ‘maintenance level’. This gives you and your doctor time to monitor how the ASM is working for you, ideally reaching a level where your seizures are eliminated or reduced with minimal side effects.

When starting an ASM or having an increase in dosage it’s a good idea to write down any changes you notice, including changes to seizure activity and side effects. You can then chat about this with your doctor, so that they can assess the effectiveness and suitability of the ASM for you.

It’s important to remember that you should never stop taking an ASM without speaking to your doctor first, as suddenly stopping ASMs can cause seizures. Also, you should never take extra ASM doses unless your doctor approves this, as it can be dangerous and worsen side effects.

Information about medication side effects is included in the Consumer Medicine Information (CMI) which can be found inside the medication package. You can also ask your pharmacist for a copy. The CMI includes plain English information about the medication and any potential common or rare side effects. The list of side effects can be off-putting, but it is important to remember that just because they are listed doesn’t mean you will necessarily experience any or all of them.

Common side effects

Some commonly reported ASM side effects include: drowsiness; irritability; mood change; weight gain or loss; dizziness; sleep disturbance; nausea; blurred vision; hair loss or unwanted hair growth; swollen gums; and, shaking hands.

Serious side effects

Some people may also be sensitive to a particular medication or experience an allergic reaction. While this is very rare it is important to seek immediate medical advice if you suddenly develop a rash, as this can be very serious.

Cognitive and learning side effects

Sometimes ASMs can affect a person’s attention and concentration. Problems finding the right words, processing new information, paying attention and concentrating can be an ASM side effect. This can make it harder to encode and remember information. Some ASMs might also affect a person’s motivation, energy levels, or mood. Sometimes these side effects will go away as you adjust to the ASM. However, it is important to bring to the attention of your doctor any side-effects that last longer or are causing you any concern.

Anti-Seizure Medication interactions

Drug interactions can happen between different ASMs, between ASMs and other types of drugs (including non-prescription or ‘over the counter’ ones), and complementary and herbal remedies. Because of this it is important to let your doctor or pharmacist know that you are taking ASMs before starting any other prescription or non-prescription drugs.

Alcohol can also affect how well an ASM works, and can make you feel more sedated as well. For some people drinking alcohol can also trigger seizures. So, if you are living with epilepsy it is a good idea to avoid or limit your alcohol consumption.

Generic medications

Every medication has a brand name, given by the pharmaceutical company that markets the drug, and a generic name, which is the drug’s active ingredient.

In recent years, some ASMs have become available in generic form in New Zealand. You might have even had a pharmacist ask “would you like the generic version of this medication?”. While the generic ones have the same active ingredients as the branded one, it is not recommended that you switch from a branded one to a generic version. Some people who have switched from the branded ASM to the generic form have experienced breakthrough seizures, increased seizures, or new side effects.

So, unless you receive approval from your doctor, the best advice is to continue taking the branded ASM prescribed for you.

Anti-seizure medications effect on driving and machine use

Some ASMs can cause drowsiness, sleepiness and slowed reaction times, especially when a medication is being introduced or a dose increased. You may have even seen a label placed on your medication pack alerting you to this risk.

So, always ask your doctor if it’s safe to drive or use heavy machinery while taking your ASM.  

Anti-seizure medications and osteoporosis

ASMs can contribute to osteoporosis. Osteoporosis is a condition of decreased bone strength (thinning of the bones) which can increase the risk of breaking a bone, particularly as you age. Your doctor may refer you for a bone density test if you are likely to be taking ASMs for an extended period of time. It may also be worthwhile considering taking a Vitamin D supplement to help with your bone health. If you are concerned about this or want to learn more, have a chat with your doctor.

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