Brands, Medical Use, Clinical Data
Drug Category
- Antiparkinson Agents
- Dopamine Agonists
- Antidyskinetics
Dosage Forms
- Subcutaneous solution (not for IV)
Brands / Synonyms
Apokyn; Apomorfin; Apomorphine Hydrochloride Hemihydrate; Apomorphinium Chloride Hemihydrate; Apormorphine; L-Apomorphine; Uprima
Indications
For the acute, intermittent treatment of hypomobility, off episodes (end-of-dose wearing off and unpredictable on/off episodes) associated with advanced Parkinson's disease.
Pharmacology
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.
Mechanism of Action
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.
Absorption
100% following subcutaneous administration
Toxicity
LD50=0.6 mmoles/kg (mice, intraperitoneal)
Biotrnasformation / Drug Metabolism
Hepatic
Contraindications
Based on reports of profound hypotension and loss of consciousness when apomorphine was administered
with ondansetron, the concomitant use of apomorphine with drugs of the 5HT3 antagonist class (including,
for example, ondansetron, granisetron, dolasetron, palonosetron, and alosetron) is contraindicated.
APOKYN is contraindicated in patients who have demonstrated hypersensitivity to the drug or its
ingredients (notably sodium metabisulfite).
Drug Interactions
5HT3 Antagonists
Based on reports of profound hypotension and loss of consciousness when apomorphine was administered
with ondansetron, the concomitant use of apomorphine with drugs of the 5HT3 antagonist class (including,
for example, ondansetron, granisetron, dolasetron, palonosetron, and alosetron) is contraindicated .
Antihypertensive Medications and Vasodilators
The following adverse events were experienced more commonly in patients receiving concomitant
antihypertensive medications or vasodilators (n = 94) compared to patients not receiving these concomitant drugs (n =
456): hypotension 10% vs 4%, myocardial infarction 3% vs 1%, serious pneumonia 5% vs 3%, serious falls 9% vs 3%, and
bone and joint injuries 6% vs 2%. The mechanism underlying many of these events is unknown, but may represent
increased hypotension . Dopamine Antagonists
Since apomorphine is a dopamine agonist, it is possible that dopamine antagonists, such as the
neuroleptics (phenoth-iazines, butyrophenones, thioxanthenes) or metoclopramide, may diminish the effectiveness of
APOKYN. Patients with major psychotic disorders, treated with neuroleptics, should be treated with dopamine agonists
only if the potential benefits outweigh the risks.
Drugs Prolonging the QT/QTc Interval
Caution should be exercised when prescribing apomorphine concomitantly with drugs that prolong the
QT/QTc interval.
Drug/Laboratory Test Interactions
There are no known interactions between APOKYN and laboratory tests.
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