Overdose
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Pharmacology
Pharmacodynamics
Norgestimate is a rapidly and completely converted prodrug, mainly of norelgestromin (17β-deacetylnorgestimate or levonorgestrel 3-oxime), but also of levonorgestrel (3-keto-17β-deacetylnorgestimate) to a lesser extent (22 ± 6% of an administered dose or about 40–70 µg) and of levonorgestrel acetate (levonorgestrel 17β-acetate) in very small amounts. Via its active metabolites, norgestimate has progestogenic activity, antigonadotropic effects, very weak androgenic activity, and no other important hormonal activity. Progestogenic activity
Norgestimate is a progestogen, or an agonist of the progesterone receptor. The relative binding affinities of norgestimate and its active metabolites for the progesterone receptor compared to promegestone (100%) are 15% for norgestimate, 10% for norelgestromin, 150% for levonorgestrel, and 135% for levonorgestrel acetate. Because of their low concentrations, norgestimate and levonorgestrel acetate are not thought to contribute significantly to the biological activity of norgestimate. In addition, although levonorgestrel binds to the progesterone receptor with much higher affinity than norelgestromin, levonorgestrel has high affinity for sex hormone-binding globulin (SHBG) (87% of that of testosterone), which may limit its activity, whereas norelgestromin does not bind to SHBG. The ovulation-inhibiting dosage of norgestimate is 200 µg/day. Androgenic activity
In addition to its progestogenic activity, norgestimate has weak androgenic activity. However, the medication shows less androgenic activity than related 19-nortestosterone progestins like levonorgestrel and norethisterone. Norgestimate and norelgestromin have negligible affinity for the androgen receptor (both 0% of the affinity of metribolone), while levonorgestrel has considerable affinity for the androgen receptor (45% of that of metribolone).
Tolvaptan, sold under the brand name Samsca among others, is an aquaretic drug that functions as a selective, competitive vasopressin receptor 2 (V2) antagonist used to treat hyponatremia (low blood sodium levels) associated with congestive heart failure, cirrhosis, and the syndrome of inappropriate antidiuretic hormone (SIADH). Tolvaptan was approved by the U.S. Food and Drug Administration (FDA) on May 19, 2009, and is sold by Otsuka Pharmaceutical Co. under the trade name Samsca. Tolvaptan, as Jynarque, was granted approval for medical use in the United States in April 2018.The U.S. Food and Drug Administration (FDA) granted tolvaptan a fast track designation for clinical trials investigating its use for the treatment of polycystic kidney disease. The FDA granted Jynarque an orphan drug designation in April 2012, for the treatment of autosomal dominant polycystic kidney disease.Tolvaptan is available as a generic medication. Medical uses
Tolvaptan (Samsca) is indicated for the treatment of clinically significant hypervolemic and euvolemic hyponatremia.Tolvaptan (Jynarque) is indicated to slow kidney function decline in adults at risk of rapidly progressing autosomal dominant polycystic kidney disease (ADPKD).Tolvaptan phosphate is a prodrug of tolvaptan, developed for intravenous administration. Tolvaptan phosphate is converted into the active drug tolvaptan in the human body following administration. Side effects
The FDA has determined that tolvaptan should not be used for longer than 30 days and should not be used in patients with underlying liver disease because it can cause liver injury, potentially leading to liver failure.