Oxcarbazepine side effects and how to avoid them

Creator: SingleCare
Published: 2022-10-19T14:31:47-04:00

Oxcarbazepine side effects include dizziness, double vision, sleepiness, and weight gain

By SingleCare Team | Oct. 19, 2022 Medically reviewed by Anne Jacobson, MD, MPH

Oxcarbazepine is a generic prescription anticonvulsant and the active ingredient in the brand-name prescription drugs Trileptal and Oxtellar XR (extended-release tablets). It is used to control partial-onset seizures in people diagnosed with epilepsy but is also prescribed off-label for trigeminal neuralgia and to control manic episodes in people with bipolar disorder. Related to the widely-used anti-seizure medication, carbamazepine, oxcarbazepine keeps nerves from firing quickly and repeatedly by interfering with the ability of nerves to build up an electric charge. In this way, oxcarbazepine prevents seizures from spreading throughout the brain. Many of its side effects are similar to those caused by carbamazepine and are mainly due to its effects on the nervous system.

Common side effects of oxcarbazepine

The most common side effects of oxcarbazepine are dizziness, double vision, and sleepiness. In order, the list of the most likely side effects are:

Dizziness
Double vision
Sleepiness
Headache
Nausea
Vomiting
Rapid eye movements (nystagmus)
Unsteadiness
Abnormal gait
Vertigo
Vision problems
Fatigue
Abdominal pain
Tremor
Diarrhea
Upset stomach
Constipation
Tiredness
Runny nose
Insomnia
Abnormal thoughts

Serious side effects of oxcarbazepine

The most serious side effects of oxcarbazepine are:

Suicidal thoughts and behaviors
Low sodium (hyponatremia)
Blood disorders
Swollen pancreas
Withdrawal seizures
Onset of generalized seizures (primarily in children)
Severe allergic reactions
Severe skin reactions

Oxcarbazepine and weight gain

At least one study has shown that children taking oxcarbazepine can experience significant increases in body weight. Weight gain in adults, however, seems to be less common. In clinical studies, people taking oxcarbazepine gained weight at just a slightly higher percentage than people taking a placebo. Adults also experienced weight loss on oxcarbazepine. Weight gain, then, seems to be uncommon among adults taking oxcarbazepine. For children, though, it is important to keep an eye on body weight when they’re on oxcarbazepine. It may be necessary to modify their diet or their activity to address weight gain.

How soon do oxcarbazepine side effects start?

Many of the most common side effects of oxcarbazepine occur early in treatment. These include sleepiness, dizziness, headache, nausea, vomiting, vision problems, and problems with thinking or concentrating. Most of the serious side effects, however, are delayed side effects and require oxcarbazepine to be taken for a while.

How long do oxcarbazepine side effects last?

Many of the milder adverse effects of oxcarbazepine improve over time as the body adapts to the drug. Some of the nervous system problems, such as drowsiness, may never go away completely, but they’ll become easier to manage. Side effects that don’t go away are usually reversible when the drug is decreased or stopped.

What are the long-term side effects of oxcarbazepine?

Oxcarbazepine is intended for long-term use—years, if possible. Although it is similar to carbamazepine, it does not seem to cause bone loss when taken over the long-term in the same way as carbamazepine or other widely-used antiepileptic drugs such as phenytoin.

Oxcarbazepine contraindications

Oxcarbazepine is never prescribed to anyone who has a known hypersensitivity to the drug or to a related drug called Aptiom (eslicarbazepine acetate).

Pregnancy

Oxcarbazepine is considered a risk during pregnancy, so it is prescribed cautiously and only if the benefits outweigh the risks. There is not only a risk for birth defects, but pregnant women on oxcarbazepine may see an increase in the number of seizures when pregnant. Regular blood tests may need to be performed.

Breastfeeding

Oxcarbazepine is prescribed cautiously in women who are breastfeeding. The drug is present in human breast milk, so it could cause problems in a nursing infant.

Children

Oxcarbazepine is FDA-approved for use in children as young as 2 years of age.

Seniors

Adults older than 65 may not be able to eliminate the drug as quickly as young adults. This slower clearance puts seniors at a higher risk of side effects, so healthcare professionals will usually start with a low dose of oxcarbazepine at the onset and try to keep the dose as low as possible. Seniors are also more vulnerable to falls, accidents, and injuries if they experience side effects like dizziness and unsteadiness. As a final consideration, seniors are also more likely to have problems with low sodium, a common side effect of oxcarbazepine.

Oxcarbazepine warnings

Although oxcarbazepine is related to carbamazepine, it does not have a serious black box warning from the FDA about suicidality or blood problems. It can cause those problems but is less likely to. There are, of course, other risks when taking oxcarbazepine.

Cautions

Some pre-existing medical conditions may cause problems in people taking oxcarbazepine.

The most serious caution involves people who are genetically susceptible to severe and potentially fatal drug reactions such as Stevens-Johnson syndrome and toxic epidermal necrolysis. These people are born with a variant of the gene HLA-B 1502. This variant is more common among people of Asian descent, so genetic testing may be performed before the drug is prescribed. Having this variant, however, is not a strict contraindication. The drug can still be taken, but, because of the risk, side effects will need to be carefully monitored.

People who have had an allergic reaction to carbamazepine are more likely to have an allergic reaction to oxcarbazepine. That doesn’t mean the drug is prohibited. It does mean that patients, their caregivers, and healthcare providers will need to watch more carefully for symptoms of an allergic reaction.

Some medical conditions can be worsened by oxcarbazepine. These include low sodium, depression, and suicidal tendencies. Kidney disease makes it difficult for the body to flush the drug out, so higher concentrations of the drug make side effects—including severe ones—more likely. Reduced doses are usually prescribed to people with kidney problems.

Finally, oxcarbazepine only helps with one type of seizure, partial seizures. It is not appropriate for other types of seizures.

Abuse and dependence

Drug abuse and physical dependence are not associated with oxcarbazepine.

Withdrawal

The sudden discontinuation of oxcarbazepine can provoke withdrawal seizures in people with a seizure disorder. When it’s time to stop, healthcare providers will prescribe a gradually tapering dose.

Overdose

Call a poison control center or get medical help if too much oxcarbazepine is taken. Symptoms of an overdose may include nausea, vomiting, sleepiness, low blood pressure, agitation, vision problems, confusion, dizziness, balance problems, and even coma.

Oxcarbazepine interactions

Most of the drug interactions related to oxcarbazepine involve a liver enzyme that breaks down some medications. In some cases, oxcarbazepine speeds up the breakdown of other drugs, making them less effective. These include some AIDS/HIV drugs, some antibiotics, some hepatitis C treatments, some blood thinners, some heart rhythm drugs, and hormonal contraceptives. Women taking birth control pills will be advised that they are at a higher risk for pregnancy if they also take oxcarbazepine. The list of drugs is very long, but be assured that healthcare professionals are aware of these interactions and will adjust doses accordingly. A few of these drugs are so compromised that they are never prescribed with oxcarbazepine.

Other drugs do the opposite: they speed up the body’s breakdown of oxcarbazepine, making it less effective. These include carbamazepine, the anti-seizure medication phenytoin, the tuberculosis treatment rifampin, and other drugs. This list also includes the popular herbal supplement, St. John’s wort, so it’s discouraged during oxcarbazepine therapy.

Some drugs make seizures more likely. They are used cautiously in anyone taking drugs like oxcarbazepine to control seizures. Some are never used, such as Wellbutrin (bupropion).

How to avoid oxcarbazepine side effects

Oxcarbazepine tends to have fewer severe side effects than its sister drug, carbamazepine. However, mild to moderate side effects are slightly more likely to occur. Still, there are ways to keep these problems at bay.

1. Tell the prescriber about all medical conditions

The first rule is to make sure the prescriber knows about all medical conditions past and present. For oxcarbazepine, the most important are:

A history of suicidal thoughts or suicide attempts
Depression or mood problems
Liver problems
Kidney problems
Any allergic reaction to carbamazepine
Pregnancy or pregnancy plans
Breastfeeding or breastfeeding plans

2. Include all the medications being taken

Your medical history is not complete without including all prescription drugs, over-the-counter medications, and dietary supplements being taken.

3. Follow instructions

Taking too much oxcarbazepine raises the risk of adverse effects. Follow the instructions to the letter. Do not take more than the prescribed dose or take it more often than prescribed. A missed dose can be taken when remembered, but skip it if it’s almost time for the next dose. Never double up a dose to make up for a missed dose.

4. Avoid driving or other risky activities

Oxcarbazepine can cause serious impairment, so it’s wise to not drive, operate machinery, or engage in risky activities or sports for a few days. Once the effects of oxcarbazepine are understood, then it’s okay to go back to driving if impairment is not too severe. If this drug makes you too drowsy or dizzy, do not drive.

How to treat side effects of oxcarbazepine

Mild side effects can usually be handled at home. However, if they persist or get worse, get medical advice from the prescribing healthcare provider. Some serious side effects, however, will require immediate medical attention. They are not always obvious, so make sure to be familiar with the signs of possibly serious problems.

Suicidal thoughts and behaviors

Thinking about suicide or showing signs of suicidality will require immediate medical attention. Any suspicion of suicidality should be reported to the prescriber, particularly:

Talking about suicide or death
Making suicide plans
Any sudden changes in mood, behaviors, or feelings
New or worse depression
New or worse anxiety
New or worse irritability
Agitation or restlessness
Panic attacks
Aggression, hostility, or violence
Acting on dangerous impulses
Unusual or extreme increase in activity or talking
Insomnia

Low sodium levels

Low sodium is a common side effect of oxcarbazepine. A temporary and small dip in sodium levels can be resolved by eating more salt. The real problem arises if sodium gets too low. That’s dangerous, so get medical attention if any of the following signs of low sodium are noticed:

An increase in seizures
Feeling more tired than usual
Feeling weak or without energy
Finding it hard to think
Confusion
Headache
Nausea

Liver problems

Oxcarbazepine can poison the liver. The only way to tell for sure is with a blood test, but the following symptoms are clues that medical help is needed:

Pain on the right side of the upper abdomen
Dark urine
Feeling less hungry than usual
Yellowing of the skin or eyes

Blood problems

Like carbamazepine, oxcarbazepine can cause blood problems. They are all considered serious side effects including reduced white blood cell counts, red blood cell counts, and reduced numbers of blood clot-forming cells called platelets. Each of these problems will have different symptoms. The most important to watch out for are:

An increase in both the frequency and severity of infections
Bleeding more than usual
Bruising more than usual
Nosebleeds
Bleeding gums
Feeling tired or fatigued more than usual
Feeling weaker than usual

Drug reactions

Potentially life-threatening drug reactions usually affect the skin. They can develop very quickly after the first symptoms, so stop taking the drug and get immediate medical attention when noticing symptoms such as:

Skin rash
Hives
Sores in the mouth and around the eyes
Skin blisters
Skin peeling

Allergic reactions

An allergic reaction to oxcarbazepine could swiftly evolve into a serious problem. It’s not always possible to tell if an allergic reaction is due to the drug, so for safety’s sake, get immediate medical attention at any of the following symptoms of an allergic reaction: