General information Sildenafil is a potent inhibitor of phosphodiesterase type V, and therefore of the breakdown of cyclic guanosine monophosphate (cGMP) in the corpora cavernosa. The increased concentration of cGMP leads to nitric oxide-mediated relaxation of the smooth muscle cells…
General information Phosphodiesterase type IV is a major regulator of cyclic adenosine monophosphate metabolism in many cell types, including smooth muscle, proinflammatory calls, and immune cells [ ]. Inhibitors of phosphodiesterase type IV, such as apremilast, cilomilast, and roflumilast, inhibit…
General information There is a range of bipyridines that are selective inhibitors of a specific isoenzyme of phosphodiesterase, F-III. These include amrinone (inamrinone), enoximone (fenoximone), milrinone, olprinone, pimobendan, sulmazole, and vesnarinone. Their clinical pharmacology has been reviewed [ ]. The…
General information Phosphatidylcholine and its derivatives form a class of phospholipids that are major components of biological membranes and pulmonary surfactant (dipalmitoyl phosphatidylcholine or lecithin). Phosphatidylcholine is an essential component of the very low-density lipoprotein (VLDL) complex that facilitates the…
General information An oral solution of sodium phosphates (dibasic sodium phosphate + monobasic sodium phosphate) is used as a laxative for the relief of occasional constipation and is used as part of a bowel-cleansing regimen in preparing patients for surgery…
See also Antiepileptic drugs General information Phenytoin is the only widely used hydantoin and, unless otherwise specified, reactions discussed here refer to phenytoin. Other hydantoin derivatives include ethotoin, mephenytoin, and albutoin (all of which are obsolete), and fosphenytoin. The latter…
General information In the past, phenylpropanolamine was marketed extensively in over-the-counter products for a variety of indications, and dietary supplements were marketed with no premarket safety evaluation, at least by the Food and Drug Administration (FDA), since for dietary supplements…
General information Phenylephrine is seldom given systemically but is still commonly used as a mydriatic for both diagnostic and therapeutic purposes. Ocular application of phenylephrine 10% in pledget form is used to produce hemostasis in laser-assisted in-situ keratomileusis (LASIK) surgery…
General information Phenylbutazone was originally a solubilizing agent for aminopyrine and was first used to treat rheumatoid arthritis and allied disorders in 1949. Phenylbutazone and its related compounds were used worldwide until the early 1980s when, following growing concern about…
General information Phentolamine is a non-selective alpha-adrenoceptor antagonist. It is used to treat hypertensive crises attributable to the effects of noradrenaline, as in pheochromocytoma and during the interaction of monoamine oxidase inhibitors with amine-containing medicaments and foods [ ]. It…