Pharmacology
Pharmacodynamics
Bremelanotide is a non-selective agonist of the melanocortin receptors, MC1 through MC5 (with the exception of MC2, the receptor of ACTH), but acting primarily as an MC3 and MC4 receptor agonist. Pharmacokinetics
The bioavailability of bremelanotide with subcutaneous injection is about 100%. Following a subcutaneous injection of bremelanotide, maximal levels occur after about one hour, with a range of 0.5 to 1.0 hours. The plasma protein binding of bremelanotide is 21%. Bremelanotide is metabolized via hydrolysis of its peptide bonds. The elimination half-life of bremelanotide is 2.7 hours, with a range of 1.9 to 4.0 hours. Bremelanotide is excreted 64.8% in urine and 22.8% in feces. Chemistry
Bremelanotide is a cyclic heptapeptide lactam analogue of α-melanocyte-stimulating hormone (α-MSH). It has the amino acid sequence Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH, and is also known as cyclo-[Nle4,Asp5,D-Phe7,Lys10]α-MSH-(4-10). Bremelanotide is an active metabolite of melanotan II that lacks the C-terminal amide group.Aside from melanotan II and endogenous melanocyte-stimulating hormones like α-MSH, other peptide analogues of the same family as bremelanotide include afamelanotide (NDP-α-MSH), modimelanotide, and setmelanotide. History
Studies in the early 1960s showed that administration of α-MSH caused sexual arousal in rats, sparking interest in α-MSH. In the 1980s, scientists at University of Arizona began developing α-MSH and analogs as potential sunless tanning agents.
Interactions
It may potentiate the antihypertensive effects of:

Drugs subject to a strong first-pass effect such as beta blockers may increase the bioavailability of hydralazine. Epinephrine (adrenaline), by its heart rate-accelerating effects as increased by hydralazine,  may lead to toxicity. Mechanism of action
Hydralazine is a drug that conducts the blood pressure lowering effects by vasoconstrictive repression. It is a direct-acting smooth muscle relaxant and acts as a vasodilator primarily in resistance arterioles, also known as the smooth muscle of the arterial bed. The molecular mechanism involves inhibition of inositol trisphosphate-induced Ca2+ release from the sarcoplasmic reticulum in arterial smooth muscle cells. By relaxing vascular smooth muscle, vasodilators act to decrease peripheral resistance, thereby lowering blood pressure and decreasing afterload. Chemistry
Hydralazine belongs to the hydrazinophthalazine class of drugs. History
The antihypertensive activity of hydralazine was discovered by scientists at Ciba, who were trying to discover drugs to treat malaria; it was initially called C-5968 and 1-hydrazinophthalazine; Cibas patent application was filed in 1945 and issued in 1949, and the first scientific publications of its blood pressure-lowering activities appeared in 1950. It was approved by the FDA in 1953.It was one of the first antihypertensive medications that could be taken by mouth. Research
Hydralazine has also been studied as a treatment for myelodysplastic syndrome in its capacity as a DNA methyltransferase inhibitor. See also
Arteriolar vasodilator
Cadralazine
Dihydralazine
Endralazine
Sodium nitroprusside

References
External links
"Hydralazine". Drug Information Portal. U.S. National Library of Medicine.