Treprostinil (marketed under the trade names Remodulin for infusion) is a vasodilator that is used for the treatment of pulmonary arterial hypertension. Pulmonary arterial hypertension (PAH) is a disease in which blood pressure is abnormally high in the arteries between the heart and lungs. PAH is characterized by symptoms of shortness of breath during physical exertion. The condition can ultimately lead to heart failure. Treprostinil is a potent oral antiplatelet agent. The major pharmacologic actions of treprostinil are direct vasodilation of pulmonary and systemic arterial vascular beds and inhibition of platelet aggregation. In animals, the vasodilatory effects reduce right and left ventricular afterload and increase cardiac output and stroke volume. Other studies have shown that treprostinil causes a dose-related negative inotropic and lusitropic effect. No major effects on cardiac conduction have been observed. Treprostinil had high affinity for the Prostaglandin D2 receptor (DP1), Prostaglandin E2 receptor EP2 subtype (EP2) and Prostaglandin D2 receptor (IP) receptors (Ki 4.4, 3.6 and 32 nM, respectively), low affinity for EP1 and EP4 receptors and even lower affinity for EP3, Prostaglandin F (FP) and thromboxane (TP) receptors. Treprostinil has demonstrated a unique effect on PPAR gamma, a transcription factor important in vascular pathogenesis as a mediator of proliferation, inflammation and apoptosis. Through a complementary, yet cyclic AMP-independent pathway, treprostinil activates PPARs, another mechanism that contributes to the anti-growth benefits of the prostacyclin class.

Travoprost, an isopropyl ester prodrug, is a synthetic prostaglandin F2 alpha analogue that is rapidly hydrolyzed by esterases in the cornea to its biologically active free acid. The travoporst free acid is potent and highly selective for the FP prostanoid receptor. Travoprost free acid is a selective FP prostanoid receptor agonist and is believed to reduce intraocular pressure by increasing the drainage of aqueous humor, which is done primarily through increased uveoscleral outflow and to a lesser extent, trabecular outflow facility. Travoprost ophthalmic solution is used for the reduction of elevated intraocular pressure in patients with open-angle glaucoma or ocular hypertension who are intolerant of other intraocular pressure lowering medications or insufficiently responsive (failed to achieve target IOP determined after multiple measurements over time) to another intraocular pressure lowering medication. Travoprost is known by the brand names of Travatan and Travatan Z, manufactured by Alcon.

Latanoprost (free acid) is a metabolite of latanoprost which has been approved for use as an ocular hypotensive drug. Latanoprost is an isopropyl ester prodrug which is converted to the Latanoprost-acid by endogenous esterase enzymes. The free acid is pharmacologically active and is 200 times more potent than latanoprost as an agonist of the human recombinant Prostaglandin F receptor. However, the free Latanoprost-acid is more irritating and less effective than Latanoprost when applied directly to the eyes of human glaucoma patients.

Epoprostenol (marketed as FLOLAN, VELETRI) is a prostaglandin that is a powerful vasodilator and inhibits platelet aggregation. Epoprostenol (PGI2, PGX, prostacyclin), a metabolite of arachidonic acid, is a naturally occurring prostaglandin with potent vasodilatory activity and inhibitory activity of platelet aggregation. FLOLAN (epoprostenol sodium) for Injection is a sterile sodium salt formulated for intravenous (IV) administration. Epoprostenol has two major pharmacological actions: (1) direct vasodilation of pulmonary and systemic arterial vascular beds, and (2) inhibition of platelet aggregation. In animals, the vasodilatory effects reduce right and left ventricular afterload and increase cardiac output and stroke volume. The effect of epoprostenol on heart rate in animals varies with dose. At low doses, there is vagally mediated brudycardia, but at higher doses, epoprostenol causes reflex tachycardia in response to direct vasodilation and hypotension. No major effects on cardiac conduction have been observed. Additional pharmacologic effects of epoprostenol in animals include bronchodilation, inhibition of gastric acid secretion, and decreased gastric emptying. No available chemical assay is sufficiently sensitive and specific to assess the in vivo human pharmacokinetics of epoprostenol. FLOLAN is indicated for the long-term intravenous treatment of primary pulmonary hypertension and pulmonary hypertension associated with the scleroderma spectrum of disease in NYHA Class III and Class IV patients who do not respond adequately to conventional therapy.

Carboprost is an analogue of naturally occurring prostaglandin F2alpha. Administered intramuscularly carboprost stimulates in the gravid uterus myometrial contractions similar to labor contractions at the end of a full term pregnancy. It is indicated for aborting pregnancy between the 13th and 20th weeks of gestation as calculated from the first day of the last normal menstrual period and for the treatment of postpartum hemorrhage due to uterine atony, which has not responded to conventional methods of management. The most frequent adverse reactions observed are related to its contractile effect on smooth muscle: vomiting, diarrhea, nausea, fever and flushing. Carboprost may augment the activity of other oxytocic agents. Concomitant use with other oxytocic agents is not recommended.

Rivenprost (ONO-4819) is a potent and selective EP4 receptor agonist. This compound can increase bone formation by stimulating osteoblast differentiation and function, possibly by modulating mesenchymal cell differentiation. Rivenprost has also been studied for its potential to prevent bone loss (in osteoporosis) and stabilize bone implants. Combined with risedronate, rivenprost may be an effective treatment for osteoporosis. A phase II study evaluating rivenprost in ulcerative colitis was terminated in 2009.

Taprenepag isopropyl (also known as PF-04217329) a prodrug of CP-544326 (active acid metabolite), a potent and selective EP(2) receptor agonist. Taprenepag isopropyl was studied in a clinical trials phase II involving patients with primary open angle glaucoma. According to Pfizer’s pipelines in May 2011, the study was discontinued.

Evatanepag (CP-533,536) is a prostaglandin E2 EP2 receptor agonist. It stimulates new bone formation on trabecular, endocortical, and periosteal surfaces and enhances fracture healing. Evatanepag was under development with Pfizer as a bone formation stimulant for therapeutic use in the healing of fractures.

Pimilprost (SM-10902) and its free acid, SM-10906 are new stable 3-oxa-methano prostaglandin (PG) I1 analogs, SM-10902 is a prodrug of SM-10906. SM-10906, but not SM-10902 was demonstrated to be an agonist for IP receptors. SM-10906 was shown to exert its anti-platelet and vasodilatory activities through the increase of the cAMP level. Pimilprost was being developed by Dainippon Sumitomo Pharma (formerly Sumitomo Pharmaceuticals) in Japan for the treatment of skin ulcers. In Japan, an NDA was filed for pimilprost and was awaiting registration. However, development appears to have been discontinued.

Piriprost (U-60, 257) is a structural analog of prostaglandin I2 (PGI2) with low IP receptor-mediated activity. It inhibits 5-LO (5-lipoxygenase). Piriprost inhibits the release of histamine and leukotrienes, implicating its role in inflammation and allergic responses. However, it was shown, that piriprost did not influence the airway responses after allergen in asthma. Nevertheless, even more, the drug was irritant to the respiratory tract than was placebo.