The Use of Dopamine Agonists in Psychiatry

[Petros Agapetos]

Ropinirole

Ropinirole is a D2, D3, and D4 dopamine receptor agonist. Its affinity for D3 receptors is 20 times greater than for D2 receptors [1]. Ropinirole is useful in treating SSRI-induced sexual dysfunction [2]. Ropinirole could be useful as an adjunctive treatment for treatment-resistant depression [3] Ropinirole is also useful in treating negative symptoms of schizophrenia [4]. Ropinirole is primarily used in the treatment of Parkinson's disease.

Pramipexole

Pramipexole is also primarily used in the treatment of Parkinson's disease. Pramipexole is also a D2-like receptor agonist: D2, D3, and D4, with the following intrinsic activities:

D2L [70%] = high partial agonist
D2S [130%] = superagonist
D3 [70%] = high partial agonist
D4 [42%] = partial agonist

Pramipexole has highest affinity for D3 receptors. Pramipexole is also useful as an adjunctive treatment for depression, anhedonia, and negative symptoms [4.1]

Cabergoline

Cabergoline is a D1, D2, D3, and D4 agonist. Cabergoline also has agonistic activity on 5HT1A and 5HT2A receptors. It is used to lower prolactin levels and treat SSRI-induced sexual dysfunction (low libido, anorgasmia). It can be used as an aphrodisiac, as it boosts libido, intensifies orgasms, and enhances sexual performance (shortens the refractory period after an orgasm), that is, with Cabergoline people can skip the post orgasm hangover [5].

Bromocriptine

Bromocriptine is a potent agonist at dopamine D2 receptors and various serotonin receptors. It also inhibits the release of glutamate. Bromocriptine is used to treat hyperprolactinaemia (high prolactin levels), neuroleptic malignant syndrome, and Parkinson's disease. Bromocriptine is also used to treat infertility, hypogonadism and diabetes II. Bromocriptine has also been found to reduce negative symptoms of schizophrenia [6].

Pharmacodynamics of Bromocriptine:

Dopamine D1 family
D1 (Ki=682 nM)
D5 (Ki=496 nM)
Dopamine D2 family
D2 (Ki=2.96 nM)
D3 (Ki=5.42 nM)
D4 (Ki=328 nM)

Serotonin 5-HT
5-HT1A (Ki=12.9 nM)
5-HT1B (Ki=355 nM)
5-HT1D (Ki=10.7 nM)
5-HT2A (Ki=107 nM)
5-HT2B (Ki=56.2 nM)
5-HT2C (Ki=741 nM)
5-HT6 (Ki=33 nM)

Note: Ki = dissociation constant. The smaller the Ki value the stronger the affinity (chemical binding strength).

[Petros Agapetos]

The following are dopamine D1 receptor agonists. Theoretically, these substances might be useful in treating negative symptoms of schizophrenia/psychosis such as avolition (lack of motivation), blunting of affect, emotional suppression, anhedonia (lack of pleasure), etc.

Stepholidine is a D1 agonist and D2 antagonist showing antipsychotic effects.

Dinapsoline is a potent selective full agonist at D1 receptors. Used for Parkinson's disease.

Dinoxyline is a potent full agonist at all five dopamine receptors.

Dihydrexidine is a moderately selective full agonist at the D1 & D5 receptors. It has a 10-fold selectivity for D1 & D5 over D2.

Pergolide is a weak D1 agonist and highly selective D2 agonist. It is also agonist on several serotonin receptors just like Bromocriptine.

Source: Wikipedia

[Petros Agapetos]

I have been using Pramipexole (1mg / day) and Bromocriptine (10mg / day), + Welbutrin 300 mg + Abilify 400mg.
For the past weeks I have been using the dopamine agonists Pramipexole and Bromocriptine and I find my affect is brighter now, mood has lifted up, more preoccupation with inner life, treats anhedonia (lack of pleasure), as well as Antipsychotic (Abilify) induced sexual dysfunction (anorgasmia, and loss of libido). My motivation is enhanced. I find myself smiling more often. I find these to be superb treatments for depression and antipsychotic- induced deficit syndrome and negative symptoms (blunting of affect etc.).