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Pronunciation |
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(ETH
in il es tra DYE ole & nor
JES trel) |
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U.S. Brand
Names |
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Lo/Ovral®; Ovral® |
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Generic
Available |
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Yes |
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Synonyms |
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Morning After Pill; Norgestrel and Ethinyl Estradiol |
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Pharmacological Index |
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Contraceptive |
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Use |
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Prevention of pregnancy; oral: postcoital contraceptive or "morning after"
pill; treatment of hypermenorrhea, endometriosis, female
hypogonadism |
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Pregnancy Risk
Factor |
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X |
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Contraindications |
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Thromboembolic disorders, cerebrovascular or coronary artery disease; known
or suspected breast cancer; undiagnosed abnormal vaginal bleeding; women smokers
>35 years of age; all women >40 years of age, hypersensitivity to drug or
components; pregnancy |
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Warnings/Precautions |
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Use of any progestin during the first 4 months of pregnancy is not
recommended; in patients with a history of thromboembolism, stroke, myocardial
infarction (especially >40 years of age who smoke), liver tumor,
hypertension, cardiac, renal or hepatic insufficiency; risk of cardiovascular
side effects increases in those women who smoke cigarettes and in women >35
years of age |
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Adverse
Reactions |
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Effects can be minimized by adjusting the estrogen/progestin balance or
dosage. See tables in Ethinyl Estradiol and Norethindrone monograph.
Cardiovascular: Peripheral edema
Endocrine & metabolic: Enlargement of breasts, breast tenderness
Gastrointestinal: Nausea, anorexia, bloating
1% to 10%:
Central nervous system: Headache
Endocrine & metabolic: Increased libido
Gastrointestinal: Vomiting, diarrhea
<1%: Hypertension, thromboembolism, myocardial infarction, edema,
depression, dizziness, anxiety, stroke, chloasma, melasma, rash, decreased
glucose tolerance, breast tumors, amenorrhea, alterations in frequency and flow
of menses, increased triglycerides and LDL, GI distress, cholestatic jaundice,
intolerance to contact lenses, increased susceptibility to Candida
infection |
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Overdosage/Toxicology |
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Toxicity is unlikely following single exposures of excessive doses
Any treatment following emesis and charcoal administration should be
supportive and symptomatic |
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Drug
Interactions |
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Ethinyl estradiol is a CYP3A3/4 and 3A5-7 enzyme substrate; CYP1A2 enzyme
inhibitor
Potential contraceptive failure with barbiturates, hydantoins, and rifampin,
nelfinavir
Concomitant penicillins or tetracyclines may lead to contraceptive failure
Increased toxicity:
Increased toxicity of carbamazepine, tricyclic antidepressants, and
corticosteroids
Increased thromboembolic potential with oral anticoagulants
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Mechanism of
Action |
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Combination oral contraceptives inhibit ovulation via a negative feedback
mechanism on the hypothalamus, which alters the normal pattern of gonadotropin
secretion of a follicle-stimulating hormone (FSH) and luteinizing hormone by the
anterior pituitary. The follicular phase FSH and midcycle surge of gonadotropins
are inhibited. In addition, oral contraceptives produce alterations in the
genital tract, including changes in the cervical mucus, rendering it unfavorable
for sperm penetration even if ovulation occurs. Changes in the endometrium may
also occur, producing an unfavorable environment for nidation. Oral
contraceptive drugs may alter the tubal transport of the ova through the
fallopian tubes. Progestational agents may also alter sperm
fertility. |
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Pharmacodynamics/Kinetics |
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Ethinyl estradiol:
Absorption: Absorbed well from GI tract
Protein binding: 98%
Metabolism: Inactivated by liver
Half-life: 6-20 hours
Elimination: Bile and urine, enterohepatic recycling
Norgestrel:
Metabolism: Reduction and conjugation
Bioavailability: Complete with no first-pass effect
Half-life, terminal: 11-45 hours
Time to peak: 0.5-2 hours |
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Usual Dosage |
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Oral: Adults: Female: Contraception: Some products recommend starting with
one schedule over the other (refer to product information for more details):
For 21-tablet package: Dosage is 1 tablet daily for 21 consecutive days,
followed by 7 days off of the medication; a new course begins on the 8th day
after the last tablet is taken.
For 28-tablet package: Dosage is 1 tablet daily without interruption.
Schedule 2 (Day 1 starter): Dose starts on first day of menstrual cycle
taking 1 tablet daily.
For 21-tablet package: Dosage is 1 tablet daily for 21 consecutive days,
followed by 7 days off of the medication; a new course begins on the 8th day
after the last tablet is taken.
For 28-tablet package: Dosage is 1 tablet daily without interruption.
If all doses have been taken on schedule and one menstrual period is missed,
continue dosing cycle. If two consecutive menstrual periods are missed,
pregnancy test is required before new dosing cycle is started.
Missed doses monophasic formulations (refer to package insert for
complete information):
One dose missed: Take as soon as remembered or take 2 tablets next day
Two consecutive doses missed in the first 2 weeks: Take 2 tablets as soon as
remembered or 2 tablets next 2 days. An additional method of contraception
should be used for 7 days after missed dose.
Two consecutive doses missed in week 3 or three consecutive doses missed at
any time: Schedule 1 (Sunday starter): Continue to take 1 tablet daily until
Sunday, then discard the rest of the pack, and a new pack is started that same
day. Schedule 2 (Day 1 starter): Current pack should be discarded, and a new
pack started that same day. An additional method of contraception should be
used for 7 days after missed dose.
Postcoital contraception or "morning after" pill: Oral (50 mcg ethinyl
estradiol and 0.5 mg norgestrel): 2 tablets at initial visit and 2 tablets 12
hours later |
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Dietary
Considerations |
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Should be administered with food at same time each day |
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Test
Interactions |
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Decreased antithrombin III
Decreased serum folate concentration
Increased prothrombin and factors VII, VIII, IX, X
Increased platelet aggregability
Increased thyroid binding globulin
Increased total thyroid hormone (T4)
Increased serum triglycerides/phospholipids |
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Dental Health: Local
Anesthetic/Vasoconstrictor
Precautions |
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No information available to require special precautions |
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Dental Health:
Effects on Dental Treatment |
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When prescribing antibiotics, patient must be warned to use additional
methods of birth control if on oral contraceptives |
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Patient
Information |
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Take exactly as directed; use additional method of birth control during first
week of administration of first cycle; photosensitivity may occur. Women should
inform their physicians if signs or symptoms of any of the following occur:
Thromboembolic or thrombotic disorders including sudden severe headache or
vomiting, disturbance of vision or speech, loss of vision, numbness or weakness
in an extremity, sharp or crushing chest pain, calf pain, shortness of breath,
severe abdominal pain or mass, mental depression or unusual bleeding.
Women should discontinue taking the medication if they suspect they are
pregnant or become pregnant |
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Nursing
Implications |
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Administer at bedtime to minimize occurrence of adverse
effects |
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Dosage Forms |
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Tablet:
Ovral®: Ethinyl estradiol 0.05 mg and norgestrel 0.5 mg
(21s and 28s)
Low-Ogestrel®: Bioequivalent to
Lo/Ovral® |
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Copyright © 1978-2000 Lexi-Comp Inc. All Rights Reserved
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