Other activities
Norgestimate and its active metabolites do not bind to other steroid hormone receptors besides the progesterone and androgen receptors and hence have no other off-target hormonal activity. This includes estrogenic, glucocorticoid, antimineralocorticoid, and neurosteroid activity. However, levonorgestrel has been found to inhibit 5α-reductase and hepatic cytochrome P450 enzymes in vitro to some extent. Pharmacokinetics
Norgestimate is rapidly and almost completely metabolized into its active metabolites, mainly norelgestromin (the primary active metabolite) and to a lesser extent levonorgestrel, upon oral ingestion. As a result, only very low concentrations (70 pg/mL) of norgestimate itself are detectable in the circulation, and only for about 6 hours after an oral dose. The oral bioavailability of norgestimate is unknown. This is due to the rapid and extensive metabolism of norgestimate, which makes determination of overall bioavailability difficult and necessitates methods other than area-under-the-curve (AUC) to do so. Peak levels of norelgestromin (3,500 pg/mL) are reached at approximately 2 hours following administration of norgestimate. Co-administration of norgestimate with a high-fat meal has been found to significantly decrease peak levels of norelgestromin, although the area-under-the-curve levels of norelgestromin are not significantly altered by food. Steady-state levels of norelgestromin and levonorgestrel are reached within 21 days of treatment with norgestimate. There is an approximate 2-fold accumulation in levels of norelgestromin and a non-linear approximate 8-fold accumulation in levels of levonorgestrel with continuous administration of norgestimate. The accumulation of levonorgestrel is thought to be a result of its high affinity for SHBG, which limits its biological activity.
Acromegaly
Octreotide can also be used in the treatment of acromegaly, a disorder of excessive growth hormone (GH). Octreotide, being a somatostatin analog, inhibits the release of GH from the pituitary gland through a process normally involved in negative feedback. In June 2020, Mycapssa (octreotide) was approved for medical use in the United States with an indication for the long-term maintenance treatment in acromegaly patients who have responded to and tolerated treatment with octreotide or lanreotide. Mycapssa is the first and only oral somatostatin analog (SSA) approved by the FDA. Gastrointestinal fistulae
Octreotide helps in management of the fistula by reducing gastrointestinal secretions and inhibiting gastrointestinal motility, thus controlling and reducing its output. The value in healing intestinal fistulas is yet to be proven and routine use is limited because of the side effects. Hypoglycemia
Octreotide is also used in the treatment of refractory hypoglycemia in neonates and sulphonylurea-induced hypoglycemia in adults. It is useful in overdose management of sulfonylurea type antidiabetic medications, when recurrent or refractory to parenteral dextrose. Mechanism of action is the suppression of insulin secretion. Gastrointestinal secretions
Octreotide is used in the palliative care setting to reduce gastrointestinal secretions, with the intention of alleviating vomiting associated with bowel obstruction. Contraindications
Octreotide has not been adequately studied for the treatment of children as well as pregnant and lactating women. The drug is given to these groups only if a risk-benefit analysis is positive.