8 Apomorphine Side Effects You Should Know About

Apomorphine is a medication that’s used to treat symptoms associated with Parkinson’s disease (PD). Apomorphine is available in two forms: Apokyn and Kynmobi. Apokyn is injected under the skin. And Kynmobi is a tablet that’s placed under your tongue. 

Apomorphine belongs to a group of medications called dopamine agonists. It works by increasing dopamine levels. This helps relieve symptoms of PD, like tremors and difficulty with coordination.

But as with all medications, apomorphine has a variety of possible side effects. Some are common and may be managed at home. Other apomorphine side effects are more serious and may warrant medical care. Below, we’ll discuss eight of the most notable apomorphine side effects to know before picking up your prescription.

1. Sleepiness

Sleepiness is one of the most common apomorphine side effects. It can happen with Kynmobi and Apokyn. Apokyn can also cause excessive yawning. Up to 40% of people taking Apokyn experienced yawning in clinical studies.

Sleepiness with apomorphine is more likely if you take other medications that make you drowsy (like sleep medications). It’s also more likely if you have certain sleep conditions, like narcolepsy. It can become dangerous if apomorphine causes you to fall asleep during daily activities, such as eating. Avoid activities that require alertness, like driving, when first starting apomorphine or after a dose increase. Once your body adjusts to apomorphine, you can see if you feel alert enough to continue with these activities.

If you experience extreme sleepiness or fall asleep at random times while taking apomorphine, let your healthcare provider know. This may be a reason to stop taking apomorphine. But don’t make any changes without talking to your provider first.

2. Nausea and vomiting

Nausea is another common apomorphine side effect. Your healthcare provider may recommend trimethobenzamide (Tigan), an antiemetic medication, to help with this. Trimethobenzamide is usually started 3 days prior to starting Apokyn or Kynmobi. It usually shouldn’t be taken for more than 2 months. It can worsen sleepiness and dizziness, which can lead to falls.

If you’re experiencing nausea, you should consider some lifestyle changes. Try to eat smaller meals more often throughout the day. Eating bland foods that are easy on the stomach, like potatoes, popsicles, and eggs, may also help.

Several over-the-counter (OTC) and prescription nausea medications are other options to provide relief. But don’t start anything without talking to your provider. Not all antiemetics are safe to use with apomorphine. For example, 5HT-3 receptor antagonists shouldn’t be used. This includes the common anti-nausea medication ondansetron (Zofran).

3. Dizziness

Apomorphine can lower your blood pressure and cause dizziness. Dizziness is most likely to happen when you first start apomorphine or if your dose is increased. 

Here are a few tips you might try to avoid and manage dizziness:

• Take your time when changing positions, especially when going from a laying down or seated position to standing up.

• Let your healthcare provider know if you take other medications that can lower blood pressure or cause dizziness. Examples include blood pressure medications like angiotensin-converting enzyme (ACE) inhibitors. It also includes nitroglycerin (Nitrostat), a medication that helps relieve chest pain. You should lie down before and after taking nitroglycerin.

• Avoid alcohol. Drinking alcohol can lead to more dizziness and falls.

• Talk to your provider about whether you should check your blood pressure at home. This could help you to know if it drops too low.

If you continue to experience dizziness with apomorphine, talk to your provider. They may suggest lowering your dose or switching you to another medication. If you experience any falls, let your provider know right away. This can be dangerous, especially in older adults.

4. Abnormal movements

Abnormal movements (dyskinesias) are a possible side effect of Apokyn. Dyskinesias are sudden, uncontrollable movements in the face, upper body, and legs. Apokyn can cause new dyskinesia, or make existing dyskinesia worse.

For some people, this side effect is mild. For others, dyskinesia can interfere with daily life. If you notice any signs of unusual facial or body movements, talk to your healthcare provider. They may recommend lowering your dose or trying another medication.

5. Swelling

Apomorphine can cause swelling. The type of swelling depends on which apomorphine product you take. Approximately 10% of people taking Apokyn report swelling in the arms and legs. If you experience swelling in these areas, let your healthcare provider know. They may adjust your dose or switch you to another medication.

About 15% of people taking Kynmobi reported swelling of the mouth and lips. People taking Kymobi also report pain, tingling sensations, and sores in the mouth and lip area. Sucking on ice chips might help with pain and swelling from Kynmobi. OTC pain relievers, like acetaminophen (Tylenol) or ibuprofen (Advil, Motrin), may also help. But first talk to your healthcare provider about whether these are safe options for you.

It’s important to note that some types of swelling are a sign of an allergic reaction. To be safe, if you have any swelling of the lips, tongue, or mouth, you should seek emergency help. Especially if it’s accompanied by redness, itching, or throat tightness.

6. Injection site reactions

Over 25% of people taking Apokyn may experience injection site reactions. These include bruising, redness, and swelling where Apokyn is injected. These reactions usually happen within a few hours of an injection.

You can help prevent injection site reactions by rotating the area where you inject apomorphine. You can rotate between the stomach area, upper arm, or upper leg. Don’t inject apomorphine into an area that’s red or feels sore.

If you experience an injection site reaction, it should only last a few days. In the meantime, ice packs, OTC pain relievers, and OTC anti-itch medications may help. But talk to your healthcare provider before you try any new medications, even if they’re OTC.

If your injection site reaction doesn’t go away after a few days, or if it gets worse, contact your healthcare provider. If you experience any symptoms of a serious reaction, including trouble breathing or swelling of the face or lips, seek emergency care.

7. Changes in thoughts and behavior

It’s possible to experience changes in your thoughts and behavior while taking apomorphine products. This includes medication-induced psychosis. People taking apomorphine may hear or see things that aren’t really there (hallucinations) or have false beliefs (delusions). This was reported more commonly in Apokyn’s clinical trials than with Kynmobi, but it’s possible with both.

If you experience symptoms of psychosis, let your healthcare provider know immediately. If you have another medical condition involving psychosis, you should avoid using apomorphine.

It’s also possible to experience trouble with impulse control when taking apomorphine products. For example, some people may have an urge to gamble or spend money uncontrollably. If you experience problems with impulse control, talk to your provider. They may suggest lowering your dose or switching you to another medication.

8. Heart problems

Apomorphine can cause heart problems. In clinical trials, 4% of people taking Apokyn experienced heart issues like chest pain (angina) and heart attack. In severe cases, the heart can stop working (cardiac arrest). People with existing heart problems may be at higher risk for these complications.

Both Apokyn and Kynmobi can cause a serious heart rhythm problem called QT prolongation. The risk is greater if you have low potassium levels, a slow heartbeat, or if you take other medications that prolong the QT interval. Examples include some antibiotics, like azithromycin (Zithromax), and some heart medications, like amiodarone (Pacerone).

If you’re taking apomorphine, watch out for symptoms of heart issues. These may include feeling like your heart is racing, dizziness, or fainting. Let your healthcare provider know if you experience any of these symptoms. If you experience intense chest pain, shortness of breath, or a loss of consciousness, you’ll need emergency care.

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If you have bothersome apomorphine side effects, contact your healthcare provider. They’ll help you decide if the benefits of apomorphine outweigh the risks. In some cases, they may lower your dose or suggest you try another medication entirely.

If you notice serious side effects, including falling asleep during daily activities, extreme dizziness, or mood changes, call your healthcare provider immediately. And if you have symptoms that feel severe (like swelling of the face or lips or trouble breathing), seek immediate medical attention.

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Written by:

Makaela Premont, PharmD

Makaela Premont, PharmD, is a pharmacist and the founder of uniquelymickie.com, a website dedicated to helping pharmacy students and pharmacists create a life that they enjoy. She received her Doctorate of Pharmacy from the University of South Carolina and is a licensed pharmacist in North Carolina.

Edited by:

Amy B. Gragnolati, PharmD, BCPS

Amy Gragnolati, PharmD, BCPS, is a pharmacy editor for GoodRx. Amy currently holds her pharmacist license in Georgia and California.

Reviewed by:

Christina Aungst, PharmD

Christina Aungst, PharmD, is a pharmacy editor for GoodRx. She began writing for GoodRx Health in 2019, transitioning from freelance writer to editor in 2021.

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