Norgestimate and Ethinyl Estradiol Tablets

An increased risk of the following serious adverse reactions has been associated with the use of oral contraceptives (see WARNINGS).

• Thrombophlebitis and venous thrombosis with or without embolism
• Arterial thromboembolism
• Pulmonary embolism
• Myocardial infarction
• Cerebral hemorrhage
• Cerebral thrombosis
• Hypertension
• Gallbladder disease
• Hepatic adenomas or benign liver tumors

There is evidence of an association between the following conditions and the use of oral contraceptives:

• Mesenteric thrombosis
• Retinal thrombosis

The following adverse reactions have been reported in patients receiving oral contraceptives and are believed to be drug-related:

• Nausea
• Vomiting
• Gastrointestinal symptoms (such as abdominal cramps and bloating)
• Breakthrough bleeding
• Spotting
• Change in menstrual flow
• Amenorrhea
• Temporary infertility after discontinuation of treatment
• Edema
• Melasma which may persist
• Breast changes: tenderness, enlargement, secretion
• Change in weight (increase or decrease)
• Change in cervical erosion and secretion
• Diminution in lactation when given immediately postpartum
• Cholestatic jaundice
• Migraine
• Allergic reaction, including rash, urticaria, angioedema
• Mental depression
• Reduced tolerance to carbohydrates
• Vaginal candidiasis
• Change in corneal curvature (steepening)
• Intolerance to contact lenses

The following adverse reactions have been reported in users of oral contraceptives and a causal association has been neither confirmed nor refuted:

• Pre-menstrual syndrome
• Cataracts
• Changes in appetite
• Cystitis-like syndrome
• Headache
• Nervousness
• Dizziness
• Hirsutism
• Loss of scalp hair
• Erythema multiforme
• Erythema nodosum
• Hemorrhagic eruption
• Vaginitis
• Porphyria
• Impaired renal function
• Hemolytic uremic syndrome
• Acne
• Changes in libido
• Colitis
• Budd-Chiari Syndrome

The following adverse reactions were also reported in clinical trials or during post-marketing experience: Infections and Infestations: vaginal infection, urinary tract infection; Psychiatric Disorders: mood altered, anxiety, insomnia; Gastrointestinal Disorders: flatulence, pancreatitis, diarrhea, constipation; Reproductive System and Breast Disorders: dysmenorrhea; ovarian cyst, vulvovaginal dryness; Neoplasms Benign, Malignant and Unspecified (Including Cysts and Polyps): benign breast neoplasm, fibroadenoma of breast, breast cyst; Nervous System Disorders: syncope, convulsion, paraesthesia; Eye Disorders: visual impairment, dry eye; Ear and Labyrinth Disorders: vertigo; Cardiac Disorders: tachycardia, palpitations; Vascular Disorders: hot flush; Respiratory, Thoracic and Mediastinal Disorders: dyspnoea; Hepatobiliary Disorders: hepatitis; Skin and Subcutaneous Tissue Disorders: night sweats, hyperhidrosis, photosensitivity reaction, pruritus; Musculoskeletal, Connective Tissue, and Bone Disorders: muscle spasms, pain in extremity, myalgia, back pain; General Disorders and Administration Site Conditions: chest pain, asthenic conditions.

Oral Contraception

Combination oral contraceptives act by suppression of gonadotropins. Although the primary mechanism of this action is inhibition of ovulation, other alterations include changes in the cervical mucus (which increase the difficulty of sperm entry into the uterus) and the endometrium (which reduce the likelihood of implantation).

Receptor binding studies, as well as studies in animals and humans, have shown that norgestimate and 17-deacetyl norgestimate, the major serum metabolite, combine high progestational activity with minimal intrinsic androgenicity.90-93 Norgestimate, in combination with ethinyl estradiol, does not counteract

the estrogen-induced increases in sex hormone binding globulin (SHBG), resulting in lower serum testosterone.90,91,94

Acne

Acne is a skin condition with a multifactorial etiology, including androgen stimulation of sebum production. While the combination of ethinyl estradiol and norgestimate increases sex hormone binding globulin (SHBG) and decreases free testosterone, the relationship between these changes and a decrease in the severity of facial acne in otherwise healthy women with this skin condition has not been established.

Pharmacokinetics

Norgestimate (NGM) and ethinyl estradiol (EE) are rapidly absorbed following oral administration. 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.

Peak serum concentrations of NGMN and EE are generally reached by 2 hours after administration of TriNessa®. Accumulation following multiple dosing of the 250 mcg NGM / 35 mcg 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 mcg to 250 mcg. Steady-state concentration of EE is achieved by Day 7 of each dosing cycle. 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.

Table 1: Summary of norelgestromin, norgestrel and ethinyl estradiol pharmacokinetic parameters

The effect of food on the pharmacokinetics of TriNessa has not been studied.

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. Ethinyl estradiol is extensively bound ( > 97%) to serum albumin and induces an increase in the serum concentrations of SHBG.

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. Ethinyl estradiol is also metabolized to various hydroxylated products and their glucuronide and sulfate conjugates.

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. 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,(17α)-(-);18,19-Dinor-5β-17- pregnan-20-yn,3α,17β-dihydroxy-13-ethyl,(17α), various hydroxylated metabolites and conjugates of these metabolites.

Special Populations

The effects of body weight, body surface area or age on the pharmacokinetics of TriNessa® have not been studied.

The effects of hepatic impairment on the pharmacokinetics of TriNessa® have not been studied. However, steroid hormones may be poorly metabolized in women with impaired liver function (see PRECAUTIONS).

The effects of renal impairment on the pharmacokinetics of TriNessa® have not been studied.

Drug-Drug Interactions

No formal drug-drug interaction studies were conducted with TriNessa®. Interactions between contraceptive steroids and other drugs have been reported in the literature (see PRECAUTIONS).

Although norelgestromin and its metabolites inhibit a variety of P450 enzymes in human liver microsomes, under the recommended dosing regimen, the in vivo concentrations of norelgestromin and its metabolites, even at the peak serum levels, are relatively low compared to the inhibitory constant (Ki).

REFERENCES

90. Anderson FD, Selectivity and minimal androgenicity of norgestimate in monophasic and triphasic oral contraceptives. Acta Obstet Gynecol Scand 1992; 156 (Supplement):15-21.

91. Chapdelaine A, Desmaris J-L, Derman RJ. Clinical evidence of minimal androgenic activity of norgestimate. Int J Fertil 1989; 34(51):347-352.

92. Phillips A, Demarest K, Hahn DW, Wong F, McGuire JL. Progestational and androgenic receptor binding affinities and in vivo activities of norgestimate and other progestins. Contraception 1989; 41(4):399-409.

93. Phillips A, Hahn DW, Klimek S, McGuire JL. A comparison of the potencies and activities of progestogens used in contraceptives. Contraception 1987; 36(2):181-192.

94. Janaud A, Rouffy J, Upmalis D, Dain M-P. A comparison study of lipid and androgen metabolism with triphasic oral contraceptive formulations containing norgestimate or levonorgestrel. Acta Obstet Gynecol Scand 1992; 156 (Supplement):34-38.