Junel

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Combination of
Estradiol Estrogen
Norethindrone Progestogen
Clinical data
Trade names Junel, Loestrin, Microgestin
AHFS/Drugs.com monograph
MedlinePlus a601050
Licence data US FDA:link
Pregnancy cat. X (US)
Legal status -only (US)
Routes Oral
Identifiers
ATC code ?

Junel (30mcg ethinylestradiol / 1.5 mg norethindrone acetate) is a monophasic combined oral contraceptive pill. It is branded generic made by Barr Pharmaceuticals. Loestrin is the brand name of Junel made by Teva Pharmaceuticals.

Available formulations[edit]

Junel 21 Day 1.5/30 which has 21 "active" pills with the estrogen and progesterone, and no placebo ("sugar") pills. Junel Fe 1.5/30 which has 21 "active" pills with the estrogen and progesterone, and also has seven iron pills. Junel ® 1/20

(Each light yellow tablet contains 1 mg norethindrone acetate and 20 mcg ethinyl estradiol.)

Junel ® 1.5/30

(Each pink tablet contains 1.5 mg norethindrone acetate and 30 mcg ethinyl estradiol.)

Junel ® Fe 1/20

(Each light yellow tablet contains 1 mg norethindrone acetate and 20 mcg ethinyl estradiol. Each brown tablet contains 75 mg ferrous fumarate.)

Junel ® Fe 1.5/30

(Each pink tablet contains 1.5 mg norethindrone acetate and 30 mcg ethinyl estradiol. Each brown tablet contains 75 mg ferrous fumarate.)

Clinical Pharmacology[edit]

Its 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. The absorption of Norethindrone acetate appears to be completely and rapidly deacetylated to norethindrone after oral administration, since the disposition of norethindrone acetate is indistinguishable from that of orally administered norethindrone. Norethindrone acetate and ethinyl estradiol are subject to first-pass metabolism after oral dosing, resulting in an absolute bioavailability of approximately 64% for norethindrone and 43% for ethinyl estradiol[1]

Norethindrone undergoes extensive biotransformation, primarily via reduction, followed by sulfate and glucuronide conjugation. The majority of metabolites in the circulation are sulfates, with glucuronides accounting for most of the urinary metabolites.[2] A small amount of norethindrone acetate is metabolically converted to ethinyl estradiol. Ethinyl estradiol is also extensively metabolized, both by oxidation and by conjugation with sulfate and glucuronide. Sulfates are the major circulating conjugates of ethinyl estradiol and glucuronides predominate in urine . The primary oxidative metabolite is 2-hydroxy ethinyl estradiol, formed by the CYP3A4 isoform of cytochrome P450. Part of the first-pass metabolism of ethinyl estradiol is believed to occur in gastrointestinal mucosa. Ethinyl estradiol may undergo enterohepatic circulation.[3]

Indications[edit]

Junel is approved by the U.S. Food and Drug Administration (FDA) for the prevention of pregnancy.

See also[edit]

Oral contraceptive formulations

References[edit]

  1. ^ DJ, Back; Back DJ, Breckenridge AM, Crawford FE, Mclver M, Orme ML’E, Rowe PH and Smith E: Kinetics (1978). "Kinetics of norethindrone in women II. Singledose kinetics.". Clin Pharmacol Ther: 448. 
  2. ^ K, Fotherby (1999). Pharmacokinetics and metabolism of progestins in humans, in Pharmacology of the contraceptive steroids,. New York: Raven Press,. 
  3. ^ K, Fotherby (1999). Pharmacokinetics and metabolism of progestins in humans, in Pharmacology of the contraceptive steroids,. New York: Raven Press,. 

External links[edit]