Norgestimate is rapidly and completely metabolized by first pass (intestinal and/or hepatic) mechanisms to norelgestromin (NGMN) and norgestrel (NG), which are the major active metabolites of norgestimate.
Norgestimate is extensively metabolized by first-pass mechanisms in the gastrointestinal tract and/or liver. Norgestimate's primary active metabolite is norelgestromin. Subsequent hepatic metabolism of norelgestromin occurs and metabolites include norgestrel, which is also active, and various hydroxylated and conjugated metabolites.
In addition to 17-deacetyl norgestimate, a number of metabolites of norgestimate have been identified in human urine following administration of radiolabeled norgestimate. These include 18,19-Dinor-17-pregn-4-en-20-yn-3-one,17-hydroxy-13-ethyl,(17alpha)-(-); 18,19-Dinor-5beta-17-pregnan-20-yn,3alpha,17beta-dihydroxy-13-ethyl,(17alpha), various hydroxylated metabolites and conjugates of these metabolites.
There is limited information on the metabolism of levonorgestrel, norethindrone and structurally related contraceptive steroids. Both levonorgestrel and norethindrone undergo extensive reduction of the alpha, beta-unsaturated ketone in ring A. Levonorgestrel also undergoes hydroxylation at carbons 2 and 16. The metabolites of both compounds circulate predominantly as sulfates. In urine, levonorgestrel metabolites are found primarily in the glucuronide form, whereas norethindrone metabolites are present in approximately equal amounts as sulfates and glucuronides. Of the progestogens structurally related to norethindrone, norethindrone acetate, ethynodiol diacetate, norethindrone enanthate, and perhaps lynestrenol, undergo rapid hydrolysis and are converted to the parent compound and its metabolites. There is no convincing evidence that norethynodrel is converted to norethindrone. Of the progestogens structurally related to levonorgestrel, it appears that neither desogestrel nor gestodene are transformed to the parent compound. However, there is evidence that norgestimate can be, at least partly, converted to levonorgestrel. ...
Herbal products containing St. John's Wort (hypericum perforatum) may induce hepatic enzymes (cytochrome P450) and p-glycoprotein transporter and may reduce the effectiveness of contraceptive steroids. This may also result in breakthrough bleeding.
Combined hormonal contraceptives have been shown to significantly decrease plasma concentrations of lamotrigine when co-administered due to induction of lamotrigine glucuronidation. This may reduce seizure control; therefore, dosage adjustments of lamotrigine may be necessary.
/SRP:/ Immediate first aid: Ensure that adequate decontamination has been carried out. If patient is not breathing, start artificial respiration, preferably with a demand valve resuscitator, bag-valve-mask device, or pocket mask, as trained. Perform CPR if necessary. Immediately flush contaminated eyes with gently flowing water. Do not induce vomiting. If vomiting occurs, lean patient forward or place on the left side (head-down position, if possible) to maintain an open airway and prevent aspiration. Keep patient quiet and maintain normal body temperature. Obtain medical attention. /Poisons A and B/
/SRP:/ Basic treatment: Establish a patent airway (oropharyngeal or nasopharyngeal airway, if needed). Suction if necessary. Watch for signs of respiratory insufficiency and assist ventilations if needed. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for pulmonary edema and treat if necessary ... . Monitor for shock and treat if necessary ... . Anticipate seizures and treat if necessary ... . For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with 0.9% saline (NS) during transport ... . Do not use emetics. For ingestion, rinse mouth and administer 5 mL/kg up to 200 mL of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool ... . Cover skin burns with dry sterile dressings after decontamination ... . /Poisons A and B/
来源:Hazardous Substances Data Bank (HSDB)
毒理性
解毒与急救
/SRP:/ 高级治疗:对于无意识、严重肺水肿或严重呼吸困难的病人,考虑进行口咽或鼻咽气管插管以控制气道。使用气囊面罩装置的正压通气技术可能有益。考虑使用药物治疗肺水肿……。对于严重的支气管痉挛,考虑给予β激动剂,如沙丁胺醇……。监测心率和必要时治疗心律失常……。开始静脉输注D5W /SRP: "保持开放",最低流量/。如果出现低血容量的迹象,使用0.9%生理盐水(NS)或乳酸林格氏液。对于伴有低血容量迹象的低血压,谨慎给予液体。注意液体过载的迹象……。使用地西泮或劳拉西泮治疗癫痫……。使用丙美卡因氢氯化物协助眼部冲洗……。 /Poisons A and B/
/SRP:/ Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in severe respiratory distress. Positive-pressure ventilation techniques with a bag valve mask device may be beneficial. Consider drug therapy for pulmonary edema ... . Consider administering a beta agonist such as albuterol for severe bronchospasm ... . Monitor cardiac rhythm and treat arrhythmias as necessary ... . Start IV administration of D5W /SRP: "To keep open", minimal flow rate/. Use 0.9% saline (NS) or lactated Ringer's if signs of hypovolemia are present. For hypotension with signs of hypovolemia, administer fluid cautiously. Watch for signs of fluid overload ... . Treat seizures with diazepam or lorazepam ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Poisons A and B/
来源:Hazardous Substances Data Bank (HSDB)
吸收、分配和排泄
诺孕酯(NGM)和炔雌醇(EE)在口服给药后迅速吸收。
Norgestimate (NGM) and ethinyl estradiol (EE) are rapidly absorbed following oral administration.
Peak serum concentrations of norelgestromin (NGMN) and ethinyl estradiol (EE) are generally reached by 2 hours after administration of MonoNessa. Accumulation following multiple dosing of the 250 ug Norgestimate (NGM)/ 35 ug dose is approximately 2-fold for NGMN and EE compared with single dose administration. The pharmacokinetics of NGMN is dose proportional following NGM doses of 180 ug to 250 ug. ... Steady-state concentrations of NGMN and NG are achieved by Day 21. Non-linear accumulation (approximately 8 fold) of norgestrel is observed as a result of high affinity binding to SHBG (sex hormone-binding globulin), which limits its biological activity.
Norelgestromin and norgestrel are highly bound (>97%) to serum proteins. Norelgestromin is bound to albumin and not to SHBG, while norgestrel is bound primarily to SHBG.
The metabolites of norelgestromin and ethinyl estradiol are eliminated by renal and fecal pathways. Following administration of 14C-norgestimate, 47% (45-49%) and 37% (16-49%) of the administered radioactivity was eliminated in the urine and feces, respectively. Unchanged norgestimate was not detected in the urine.