Apomorphine

Apomorphine (Apokyn, Ixense, Spontane, Uprima) is a non-selective dopamine agonist which activates both D₁-like and D₂-like receptors, with some preference for the latter subtypes. It is historically a morphine decomposition product by boiling with concentrated acid, hence the -morphine suffix. Apomorphine does not actually contain morphine or its skeleton, or bind to opioid receptors. The apo- prefix relates to it being an aporphine derivative.

Historically, apomorphine has been tried for a variety of uses including psychiatric treatment of homosexuality in the early 20th century, and more recently in treating erectile dysfunction. Currently, apomorphine is used in the treatment of Parkinson's disease. It is a potent emetic (i.e., it induces vomiting) and should not be administered without an antiemetic such as domperidone. The emetic properties of apomorphine are exploited in veterinary medicine to induce therapeutic emesis in canines that have recently ingested toxic or foreign substances.

It was also successfully used as an unofficial treatment of heroin addiction, a purpose for which it was championed by the author William S. Burroughs. 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. Early studies involved aversion therapy in alcoholism and anxiety, and modern reports are rather anecdotal.

For treatment of erectile dysfunction, it is believed that dopamine receptors in the hypothalamic region of the brain are the main target, as although dopamine receptors in the penis do facilitate erection, they do so far more weakly than those in the brain.