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Side effects

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Anti-Seizure Medications (ASMs) may sometimes have side effects. As these medications act on the brain, drowsiness, sedation, nausea and unsteadiness may occur when the medication is first taken and may soon wear off. If side effects persist they should be reported back to the doctor. Other side effects may be common or rare, mild or serious. Your doctor or pharmacist can explain what side effects to watch out for on your medication. Watch for any unusual symptoms or behaviours and report these to your medical team. Rashes from some medications (and Lamotrigine especially) can become serious and even life-threatening and require prompt medical attention. Other side effects may include dizziness, drowsiness, weight gain or loss, tremor, nausea, mood change, double vision and concentration difficulties. 

Chronic side effects may occur when medications are taken over a long time. However, these effects can be reduced, for example, good dental hygiene can help swollen gums, a side effect of the prolonged use of phenytoin. Bone health may be affected by some medications over a long time. If you are at risk of this, your doctor may suggest a DEXA bone scan to see if your bones are becoming thin or brittle as there is a risk of osteoporosis. Your doctor may also recommend you take calcium supplementation. Always report suspected side effects to your team but don’t stop taking your medication unless your doctor advises you to. Drug level monitoring is relevant with some drugs, such as Epanutin (Phenytoin). Make sure to read the patient information leaflet supplied with your medication to see the full list of possible side effects.

Interactions with other prescribed medications

Some prescribed drugs for other medical conditions can affect epilepsy or interact with epilepsy medication. Certain antibiotics, anti-malaria drugs, pain medications, steroids, broncho-dilators and anti-histamines are just some that can do this. Other prescribed medications that can have these effects include anti-depressants, anti-psychotics and benzodiazepines. Epilepsy medications can also affect some oral contraceptives. When you are being prescribed other drugs always mention your epilepsy treatment and discuss possible interactions with your doctor.

Interactions with over the counter medicines

If you are choosing to buy over the counter medicines and supplements, it is important to check with the pharmacist if there will be any problems taking these with your epilepsy and your medication. Some cold and flu medicines, decongestants and antihistamines have been reported to increase risk of seizures.

Food and Drink

Grapefruit and grapefruit juice can interact with many medicines including some epilepsy medications such as carbamazepine and oxcarbazepine and emergency medications such as midazolam and valium. Energy drinks with high levels of caffeine can provoke seizures too. While some people may feel their seizures are affected by artificial sweeteners, the evidence for this is inconclusive. Alcohol is a trigger for seizures and should be kept to moderate levels, or as guided by your doctor.

Reporting Side Effects/Safety Issues 

What is a suspected safety issue?
It is important to note that all medications carry potential risks and side effects and many people with epilepsy will report experiencing side effects from their ASMs. As noted in earlier paragraphs, it is very important that you report these to your medical team and prescribing clinician. However, it is crucial that side effects are also reported to the Health Products Regulatory Authority (HPRA). A suspected safety issue is something that you think may have been caused by a health product, including a medicine or medical device. This can include known side effects listed in the leaflet that comes with the health product, as well as a safety issue that isn't listed or is not expected. It may occur soon after you have used the health product, or sometimes only long after use. Typical side effects to medicines These can include an allergic reaction, rash, nausea, headache, for example. Typical safety issues with medical devices These can include an incorrect test result, a problem with a pacemaker or an insulin pump not working.

What can I do?
You can report a suspected safety issue to the HPRA using its online reporting system, by post, or by telephone. Full details on how to submit a report are available on the HPRA website. You can submit a report for yourself or someone in your care. When you submit a report, you give the HPRA information that can help to make medicines and medical devices safer for others. Every report counts and helps to make health products as safe as possible.

What happens when I report to the HPRA?
When you submit a report, the HPRA:

  • Will review your report 
  • Will reply to let you know it has been received 
  • May contact you for more information about your experience.

Reports can help to find new safety issues or trends and are used together with all new information about the health product. Making a report to the HPRA does not mean that the health product caused the safety issue. However, it is important to share the information with the HPRA so it can be looked at. If you are worried about your health or the health of someone you care for, it is really important to speak to your doctor, pharmacist, or nurse. 

By reporting side effects that you may experience to the HPRA, this helps to ensure that medicines on the market are as safe as possible and that patients on ASMs have full information about the medication they are taking. You can report a suspected side effect in several ways: