It is important to understand precautions and warnings with apomorphine before starting this medication. For example, make sure your healthcare provider is aware of your medical history, as apomorphine can make some conditions worse. Precautions and warnings with apomorphine also include potential drug interactions, possible allergic reactions, and the safety of using the medication when pregnant or breastfeeding.

• Low blood pressure (hypotension)
• Asthma
• Liver disease, such as liver failure, cirrhosis, or hepatitis
• Kidney disease, such as kidney failure (renal failure)
• An irregular heart rhythm (arrhythmia)
• A slow heart rate (bradycardia)
• Heart problems of any kind
• Low blood potassium (hypokalemia) or low blood magnesium (hypomagnesemia)
• Any allergies, including allergies to foods, dyes, or preservatives.
   

• Pregnant or thinking of becoming pregnant
• Breastfeeding.
   

• Apomorphine should never be injected into a vein, as this can cause blood clots.
   
• Apomorphine almost always causes severe nausea and vomiting. In order to avoid this problem, your healthcare provider should put you on trimethobenzamide (Tigan^®), starting three days before your first dose of apomorphine and continuing for at least two months. While some people may eventually be able to stop taking trimethobenzamide, many will need to continue the medication as long as they take apomorphine.
   
• Apomorphine may increase the risk of a dangerous arrhythmia known as QT prolongation. Low blood potassium or magnesium levels, a slow heart rate, certain medications (known as QT-prolonging medications), and certain heart problems can increase the risk of QT prolongation.
   
• Apomorphine can cause dangerously low blood pressure (hypotension). In order to help prevent this problem, your first dose of apomorphine (a "test dose") should be taken under the supervision of your healthcare provider, who will monitor your blood pressure for at least an hour after the dose. Let your healthcare provider know if you develop signs of low blood pressure, such as dizziness, lightheadedness, or fainting.
   
• Apomorphine can cause falling, often due to low blood pressure or fainting. Let your healthcare provider know if you have any falls (serious or not) while taking apomorphine.
   
• Apomorphine can cause hallucinations (seeing, hearing, feeling, smelling, or even tasting things that are not really there). This is not a rare apomorphine side effect, as it occurs in up to 14 percent of people taking the medication.
   
• There have been reports of people falling asleep unexpectedly during daily activities while taking apomorphine. It may be a good idea to avoid driving or operating heavy machinery until you know how apomorphine will affect you.
   
• Apomorphine may increase the risk of heart problems, such as heart attacks, chest pain, or cardiac arrest. It is thought that these effects are due to low blood pressure (as very low blood pressure can deprive the heart of oxygen).
   
• Injection site reactions (such as bruising or itching at the site of the injection) are common with apomorphine.
   
• Apomorphine contains sodium metabisulfite, a sulfite product. Do not take apomorphine if you are allergic to sulfites. People with asthma may have a higher risk for sulfite allergies.
   
• Rarely, there have been reports of people abusing apomorphine, usually for its sexually stimulating effects. If you feel the urge to use apomorphine inappropriately, please discuss this with your healthcare provider.
   
• Apomorphine can cause (or worsen) dyskinesias, uncontrollable muscle movements.
   
• Seek immediate medical attention if you have a painful penile erection that does not go away (this is known medically as priapism). Delaying treatment for this problem can lead to permanent damage (which can cause impotence).
   
• If you have liver or kidney disease, a lower apomorphine dosage may be recommended. In some cases, apomorphine may not be a good choice for you.
   
• In animal studies, apomorphine caused retinal (eye) problems in rats. It is not known if the same problem can occur in humans.
   
• Apomorphine can potentially interact with several medications (see Drug Interactions With Apomorphine).
   
• Apomorphine is considered a pregnancy Category C medication. This means that it may not be safe for use during pregnancy, although the full risks are not known (see Apokyn and Pregnancy).
   
• It is not known if apomorphine passes through breast milk. Therefore, if you are breastfeeding or plan to start, discuss this with your healthcare provider prior to taking the drug (see Apokyn and Breastfeeding).