Terguride (INN), also known as trans-dihydrolisuride, is a serotonin receptor antagonist and dopamine receptor agonist of the ergoline family. Terguride is approved for and used in the treatment of hyperprolactinemia. Terguride is an oral, potent antagonist of 5-HT2B and 5-HT2A (serotonin) receptors. Serotonin stimulates the proliferation of pulmonary artery smooth muscle cells and induces fibrosis in the wall of pulmonary arteries. Together, this causes vascular remodeling and narrowing of the pulmonary arteries. These changes result in increased vascular resistance and PAH. Due to the potential anti-proliferative and anti-fibrotic activity of terguride, this potential medicine could offer the hope of achieving reversal of pulmonary artery vascular remodeling and attenuation of disease progression. In May 2008, terguride was granted orphan drug status for the treatment of pulmonary arterial hypertension. In May 2010 Pfizer purchased worldwide rights for the drug.

Spiperone (Spiroperidol; brand name: Spiropitan (JP)) is a typical antipsychotic and research chemical belonging to the butyrophenone chemical class. Spiperone is selective D2 dopamine receptor antagonist; α1B-adrenoceptor antagonist; mixed 5-HT2A/5-HT1 serotonin receptor antagonist. Additionally, spiperone was identified by compound screening to be an activator of Ca2+ activated Cl− channels (CaCCs), thus a potential target for therapy of cystic fibrosis. Spiperone is widely used as a pharmacological tool for studying neurotransmitter receptors.

Perospirone (Lullan®) is an atypical antipsychotic of the azapirone family. It is used in Japan for the treatment of schizophrenia and acute cases of bipolar mania. Its primary mode of action is through antagonism of serotonin 5-HT2A and dopamine D2 receptors.

Docarpamine (marketed under the tradename Tanadopa) is a dopamine prodrug developed in Japan for the treatment of chronic heart failure. The drug does not cross the blood-brain barrier and shows no effect on CNS activity. It is supposed that the drug exerts its action by activating dopamine receptor D1.

Metopimazine, a phenothiazine derivative, is a dopamine D2 receptor antagonist. It exerts its antiemetic effects via the chemoreceptor trigger zone. Metopimazine showed potent alpha-adrenergic blocking activity, showed histamine H1 antagonism, and induced palpebral ptosis. Metopimazine can occasionally be associated with orthostatic hypotension, which probably relates to its affinity for the α1-adrenoceptor. Therapeutic doses of metopimazine are likely to produce sedation and side-effects related to autonomic blockade. Metopimazine (Vogalene®) is indicated for the prevention and treatment of nausea and vomiting.

Piribedil is an antiparkinsonian agent which acts as D2 and D3 receptor agonist. In European countries and worldwide it is used as a monotherapy or in combination with dopatherapy for treatment of Parkinson's disease, cognitive impairment and obliterating arteriopathy.