Dopamine agonist

A dopamine agonist is a compound that activates dopamine receptors in the absence of dopamine. Dopamine agonists activate signaling pathways through the dopamine receptor and trimeric G-proteins, ultimately leading to changes in gene transcription.

Uses
Some medical drugs act as dopamine agonists and can treat hypodopaminergic (low dopamine) conditions; they are typically used for treating Parkinson's disease and certain pituitary tumors (prolactinoma), and may be useful for restless legs syndrome (RLS). Both Requip (Ropinirole) and Mirapex (Pramipexole) are FDA-approved for the treatment of RLS. There is also an ongoing clinical trial to test the effectiveness of the dopamine agonist Requip (ropinirole) in reversing the symptoms of SSRI-induced sexual dysfunction and Post-SSRI sexual dysfunction (PSSD). Additionally, a systematic review and meta-analysis concluded that prophylactic treatment with cabergoline reduces the incidence, but not the severity, of ovarian hyperstimulation syndrome (OHSS), without compromising pregnancy outcomes, in females undergoing stimulated cycles of in vitro fertilization (IVF).

Side-effects
Some of the common side effects of dopamine agonists include:
 * Euphoria
 * Hallucinations
 * Causing or worsening psychosis
 * Orthostatic hypotension
 * Increased orgasmic intensity
 * Weight loss
 * Nausea
 * Insomnia
 * Unusual tiredness or weakness
 * Dizziness, drowsiness, lightheadedness, or fainting
 * Twitching, twisting, or other unusual body movements
 * Pathological addiction (gambling, shopping, internet pornography, hyper-sexuality) – specifically D3-preferring agonists

Examples
Examples of dopamine agonists include:


 * Parlodel (bromocriptine)
 * Dostinex (cabergoline)
 * Permax (pergolide) - Removed from market in America March 29, 2007.


 * Mirapex and Sifrol (pramipexole)
 * Requip (ropinirole)
 * Apokyn (apomorphine)
 * Neupro (rotigotine)
 * Norprolac (Quinagolide)

Some, such as fenoldopam, are selective for dopamine receptor D1.