Despite anecdotal evidence that this offers a plausible route to an abstinence-based mode, no clinical trials have ever tested this hypothesis. A recent study indicates that apomorphine might be a suitable marker for assessing central dopamine system alterations associated with chronic heroin consumption. There is, however, no clinical evidence that apomorphine is an effective and safe treatment regimen for opiate addiction. Medical uses
Apomorphine is used in advanced Parkinsons disease intermittent hypomobility ("off" episodes), where a decreased response to an anti-Parkinson drug such as L-DOPA causes muscle stiffness and loss of muscle control. While apomorphine can be used in combination with L-DOPA, the intention is usually to reduce the L-DOPA dosing, as by this stage the patient often has many of dyskinesias caused by L-DOPA and hypermobility periods. When an episode sets in, the apomorphine is injected subcutaneously or applied sublingually, and signs subside. It is used an average of three times a day. Some people use portable mini-pumps that continuously infuse them with apomorphine, allowing them to stay in the "on" state and using apomorphine as an effective monotherapy. Contraindications
The main and absolute contraindication to using apomorphine is the concurrent use of adrenergic receptor antagonists; combined, they cause a severe drop in blood pressure and fainting. Alcohol causes an increased frequency of orthostatic hypotension (a sudden drop in blood pressure when getting up), and can also increase the chances of pneumonia and heart attacks.
Dopamine antagonists, by their nature of competing for sites at dopamine receptors, reduce the effectiveness of the agonistic apomorphine.IV administration of apomorphine is highly discouraged, as it can crystallize in the veins and create a blood clot (thrombus) and block a pulmonary artery (pulmonary embolism). Side effects
Nausea and vomiting are common side effects when first beginning therapy with apomorphine; antiemetics such as trimethobenzamide or domperidone, dopamine antagonists, are often used while first starting apomorphine. Around 50% of people grow tolerant enough to apomorphines emetic effects that they can discontinue the antiemetic.Other side effects include orthostatic hypotension and resultant fainting, sleepiness, dizziness, runny nose, sweating, paleness, and flushing. More serious side effects include dyskinesias (especially when taking L-DOPA), fluid accumulation in the limbs (edema), suddenly falling asleep, confusion and hallucinations, increased heart rate and heart palpitations, and persistent erections (priapism). The priapism is caused by apomorphine increasing arterial blood supply to the penis. This side effect has been exploited in studies attempting to treat erectile dysfunction. Pharmacology
Mechanism of action
Apomorphines R-enantiomer is an agonist of both D1 and D2 dopamine receptors, with higher activity at D2. The members of the D2 subfamily, consisting of D2, D3, and D4 receptors, are inhibitory G protein–coupled receptors. The D4 receptor in particular is an important target in the signaling pathway, and is connected to several neurological disorders.