The invention describes novel nitrosated and/or nitrosylated prostaglandins, and novel compositions comprising at least one nitrosated and/or nitrosylated prostaglandin, and, optionally, at least one compound that donates, transfers or releases nitric oxide, elevates endogenous levels of endothelium-derived relaxing factor, stimulates endogenous synthesis of nitric oxide or is a substrate for nitric oxide synthase, and/or at least one vasoactive agent. The invention also provides novel compositions comprising at least one prostaglandin and at least one S-nitrosothiol compound, and, optionally, at least one vasoactive agent. The prostaglandin is preferably a prostaglandin E.sub.1 compound, more preferably alprostadil, and the S-nitrosothiol compound is preferably S-nitrosoglutathione. The invention also provides methods for treating or preventing sexual dysfunctions in males and females, for enhancing sexual responses in males and females, and for treating or preventing cerebrovascular disorders, cardiovascular disorders, benign prostatic hyperplasia (BPH), glaucoma, peptic ulcers or for inducing abortions.