with the combination of estradiol and norgestimate in postmenopausal women, with greater than or equal to 5% incidence over one year, include headache (23%), upper respiratory tract infection (21%), breast pain (16%), back pain (12%), abdominal pain (12%), flu-like symptoms (11%), arthralgia (9%), vaginal bleeding (9%), dysmenorrhea (8%), sinusitis (8%), vaginitis (7%), pharyngitis (7%), fatigue (6%), pain (6%), nausea (6%), viral infection (6%), flatulence (5%), tooth disorder (5%), myalgia (5%), dizziness (5%), depression (5%), and coughing (5%). Overdose Interactions 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). In addition to their lack of affinity for the androgen receptor, norgestimate and norelgestromin have virtually no affinity for SHBG, and therefore do not displace testosterone from this carrier protein (although levonorgestrel does still bind with high affinity to SHBG and hence could increase free testosterone levels via occupation of SHBG). In accordance, clinical trials of norgestimate have observed minimal androgenic side effects in women treated with the medication. As an example, clinical studies have found that norgestimate does