Drug information of Apomorphine

Apomorphine


A derivative of morphine that is a dopamine D2 agonist. It is a powerful emetic and has been used for that effect in acute poisoning. It has also been used in the diagnosis and treatment of parkinsonism, but its adverse effects limit its use.

Mechanism of effect

The precise mechanism of action of apomorphine as a treatment for Parkinson's disease is unknown, although it is believed to be due to stimulation of post-synaptic dopamine D2-type receptors within the brain. Apomorphine has been shown to improve motor function in an animal model of Parkinson's disease. In particular, apomorphine attenuates the motor deficits induced by lesions in the ascending nigrostriatal dopaminergic pathway with the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in primates.

Pharmacodynamic

Apomorphine is a type of dopaminergic agonist, a morphine derivative which primarily affects the hypothalamic region of the brain. Drugs containing this substance are sometimes used in the treatment of Parkinson's disease or erectile dysfunction. In higher doses it is a highly effective emetic.

Pharmacokinetics

Peak Plasma Time:10-60 min

Half-life, elimination: 30-60 min

Vd: 218 L

Metabolism: Sulfation, oxidation, glucuronidation, N-demethylation, and cetechol-O methyltransferase

Excretion: Urine (93%); feces (16%)

Drug indications

Hypomobility  associated with advanced Parkinson's disease.

Dosage

Adult

Parkinson Disease

Initial: 2 mg (0.2 mL) SC

Dose titration

  • Titrate on the basis of effectiveness and tolerance, up to a maximum dose of 6 mg
  • Average frequency of dosing in clinical trials was TID

Premedication

  • High incidence of nausea and vomiting with treatment; initiate an antiemetic (eg, trimethobenzamide 300 mg TID) 3 days prior to the initial apomorphine dose
  • Treatment with trimethobenzamide should only be continued as long as necessary to control nausea and vomiting, and generally no longer than 2 months after initiation of treatment

Pediatric

Safety and efficacy not established

Drug contraindications

Hypersensitivity to apomorphine

Sulfite/sulfur allergies (contains sulfite)

Do not use 5-HT3 antagonist antiemetics (eg, granisetron, dolasetron) - risk of profound hypotension and loss of consciousness

Side effects

Dizziness or postural hypotension , Dyskinesia , Injection site reaction , Nausea or vomiting , Somnolence , Yawning , Anxiety, Arthralgia, Back pain, CHF, Confusion , Depression, Edema , Hallucinations , Headache, Injection site pain, Insomnia, Limb pain, Rhinorrhea , UTI

Alerts

For subcutaneous use only; thrombus formation and pulmonary embolism have followed IV administration owing to crystallization of apomorphine

Severe nausea and vomiting occurs at recommended doses; because of this, premedicate with trimethobenzamide; trimethobenzamide reduces incidence of nausea and vomiting during first 4 weeks of therapy; patients treated with trimethobenzamide experience greater incidence of somnolence, dizziness and falls; benefit of treatment with trimethobenzamide must be balanced with risk for those adverse events, and treatment with trimethobenzamide should only be continued as long as necessary to control nausea and vomiting, which should generally be no longer than two months

Falling asleep during activities of daily living and daytime somnolence may occur

Syncope and hypotension/orthostatic hypotension may occur

Falls may occur, or increase

May cause hallucinations and psychotic-like behavior

May cause dyskinesia or exacerbate pre-existing dyskinesia

May cause problems with impulse control and impulsive behaviors; consider dose reduction or discontinuing

Coronary events (eg, angina, MI, cardiac arrest, and/or sudden death) reported in clinical trials; apomorphine reduces resting systolic and diastolic BP and may have the potential to exacerbate ischemia

May prolong QTc and cause torsades de pointes or sudden death

Withdrawal-emergent hyperpyrexia and confusion reported

Patients with Parkinson disease have a higher risk for melanoma compared with the general population; it is unclear if this is due to the disease or medications; providers are advised to monitor for melanoma regularly

Points of recommendation

Follow all directions on your prescription label. Never use apomorphine in larger amounts, or use it for longer than recommended. Tell your doctor if the medicine seems to stop working as well.

Apomorphine is injected under the skin.

Use a different place each time you give an injection. Do not inject into the same place two times in a row.

Apomorphine can cause severe nausea and vomiting. To prevent these symptoms, you may be given anti-nausea medication to start taking a few days before you start using apomorphine. Keep taking the anti-nausea medicine throughout your treatment with apomorphine.

Do not take any anti-nausea medicine without first asking your doctor. Some anti-nausea medicines can increase certain side effects of apomorphine, or can make your Parkinson's symptoms worse.

Do not use apomorphine if it has changed colors or has particles in it.

Your blood pressure will need to be checked often.

Do not stop using apomorphine suddenly, or you could have unpleasant withdrawal symptoms. Ask your doctor how to safely stop using apomorphine.

If you stop using apomorphine for 7 days or longer, ask your doctor before restarting the medication. You may need to restart with a lower dose.

Use a disposable needle only once.

Store apomorphine cartridges at room temperature away from moisture and heat.

Use the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not use extra medicine to make up the missed dose.

Pregnancy level

C


Ask a Pharmacist


User's questions
    No comments yet.