D4 receptor agonists

Apomorphine, sold under the brand name Apokyn among others, is a type of aporphine that functions as a non-selective dopamine agonist which activates both D2-like and, to a much lesser extent, D1-like receptors. It also acts as an antagonist of 5-HT2 and α-adrenergic receptors with high affinity. The compound is an alkaloid belonging to nymphaea caerulea, or blue lotus, but is also historically known as a morphine decomposition product made by boiling morphine with concentrated acid, hence the -morphine suffix. Contrary to its name, apomorphine does not actually contain morphine or its skeleto

Cabergoline, sold under the brand name Dostinex among others, is a dopaminergic medication used in the treatment of high prolactin levels, prolactinomas, Parkinson's disease, and for other indications. It is taken by mouth.

Rotigotine, sold under the brand name Neupro among others, is a dopamine agonist of the non-ergoline class of medications indicated for the treatment of Parkinson's disease and restless legs syndrome. It is formulated as a once-daily transdermal patch which provides a slow and constant supply of the drug over the course of 24 hours.

Lisuride, sold under the brand name Dopergin among others, is a monoaminergic medication of the ergoline family which is used in the treatment of Parkinson's disease, migraine, and high prolactin levels. It is taken by mouth.

Pergolide, sold under the brand name Permax and Prascend (veterinary) among others, is an ergoline-based dopamine receptor agonist used in some countries for the treatment of Parkinson's disease. Parkinson's disease is associated with reduced dopamine synthesis in the substantia nigra of the brain. Pergolide acts on many of the same receptors as dopamine to increase receptor activity.

Escaline (E), also known as 3,5-dimethoxy-4-ethoxyphenethylamine, is a psychedelic drug of the phenethylamine and scaline families related to mescaline. It is the 4-ethoxy analogue of mescaline (3,4,5-trimethoxyphenethylamine) and the phenethylamine (non-α-methyl) analogue of 3C-E (3,5-dimethoxy-4-ethoxyamphetamine). The drug has been encountered as a novel designer drug.