Apomorphine Side Effects: What to Expect and When to Call Your Doctor

Apomorphine is a powerful medication that can dramatically improve quality of life for people with advanced Parkinson's disease—but it also comes with a significant side effect profile that every patient and caregiver should understand before starting treatment. This guide covers the most common side effects, the most serious warnings, and the specific symptoms that require immediate medical attention.

The Most Common Side Effect: Nausea and Vomiting

Nausea and vomiting are so common with apomorphine that an anti-nausea medication is required before starting treatment. The FDA recommends that patients begin trimethobenzamide (Tigan) 300 mg three times daily starting 3 days before the first dose of apomorphine. This antiemetic significantly reduces—but does not eliminate—nausea in most patients.

Critically important: Do NOT take ondansetron (Zofran), granisetron, dolasetron, palonosetron, or alosetron with apomorphine. These 5-HT3 antagonist antiemetics are absolutely contraindicated—they can cause profound hypotension (dangerously low blood pressure) and loss of consciousness. If you are prescribed one of these medications for any reason while on apomorphine, contact your doctor immediately.

Common Side Effects of Apomorphine

The following side effects are common and often improve over time as your body adjusts to apomorphine:

Nausea and vomiting (very common—pretreatment required)

Orthostatic hypotension (dizziness or lightheadedness when standing up—stand slowly from sitting or lying positions)

Somnolence (drowsiness; can include sudden, unexpected sleep attacks)

Dyskinesia (involuntary movements—apomorphine may worsen existing dyskinesias or cause new ones)

Injection site reactions (bruising, swelling, redness, or nodules at the injection site—rotate injection sites regularly)

Sweating and yawning

Edema (swelling in the legs, feet, or ankles)

Serious Side Effects That Need Prompt Medical Attention

Call your doctor right away if you experience:

Hallucinations or confusion: Seeing or hearing things that aren't there, delusional thoughts, or disorganized thinking. Apomorphine can cause or worsen psychosis, especially in people who already have neuropsychiatric symptoms.

Impulse control disorders: Unusually strong urges to gamble, have sex, eat, or spend money. Some patients develop these behaviors on dopamine agonists. Tell your doctor and your family members about this risk so they can watch for signs.

Heart problems: Chest pain, irregular heartbeat, shortness of breath, or fainting. Apomorphine prolongs the QTc interval on ECG, which increases the risk of serious cardiac arrhythmias.

Sudden sleep attacks: Falling asleep suddenly without warning during daily activities including driving, eating, or talking. Do not drive until you know how apomorphine affects you.

Severe allergic reaction: Hives, itching, rash, difficulty breathing, or swelling of the face, lips, or throat.

Call 911 or Go to the ER If You Experience:

Loss of consciousness

Severe low blood pressure with fainting

Chest pain or suspected heart attack

Signs of apomorphine overdose: severe low blood pressure, extreme drowsiness, vomiting that won't stop

Prolonged erection lasting more than 4 hours (priapism)

Side Effects Specific to Onapgo (Continuous Infusion)

Onapgo—the wearable continuous infusion device—has all the same side effects as Apokyn injection, plus additional infusion-site specific issues:

Infusion site nodules (hard lumps under the skin)—rotate sites daily

Infusion site infections—watch for increasing redness, warmth, or discharge

Orthostatic intolerance (especially during the first weeks of therapy)

How to Minimize Apomorphine Side Effects

Take trimethobenzamide as prescribed—do not skip doses

Avoid alcohol while using apomorphine

Stand up slowly from sitting or lying positions

Rotate injection sites with every dose—stomach, upper arm, or upper leg

Do not drive until you know how apomorphine affects your alertness

For information on which medications interact with apomorphine, read our guide: Apomorphine drug interactions: what to avoid and what to tell your doctor.

And if you need help finding apomorphine in stock, medfinder can locate which pharmacies near you have it available.