Prescription Drug Information: Microgestin 1/20 (Page 3 of 7)

11. Headache

The onset or exacerbation of migraine or development of headache with a new pattern which is recurrent, persistent, or severe requires discontinuation of oral contraceptives and evaluation of the cause.

12. Bleeding Irregularities

Breakthrough bleeding and spotting are sometimes encountered in patients on oral contraceptives, especially during the first three months of use. Non-hormonal causes should be considered, and adequate diagnostic measures taken to rule out malignancy or pregnancy in the event of breakthrough bleeding, as in the case of any abnormal vaginal bleeding. If pathology has been excluded, time or a change to another formulation may solve the problem. In the event of amenorrhea, pregnancy should be ruled out.

Some women may encounter post-pill amenorrhea or oligomenorrhea, especially when such a condition was preexistent.


1. Patients should be counseled that this product does not protect against HIV infection (AIDS) and other sexually transmitted diseases.

2. Physical Examination and Follow-Up

It is good medical practice for all women to have annual history and physical examinations, including women using oral contraceptives. The physical examination, however, may be deferred until after initiation of oral contraceptives if requested by the woman and judged appropriate by the clinician. The physical examination should include special reference to blood pressure, breasts, abdomen and pelvic organs, including cervical cytology, and relevant laboratory tests. In case of undiagnosed, persistent or recurrent abnormal vaginal bleeding, appropriate measures should be conducted to rule out malignancy. Women with a strong family history of breast cancer or who have breast nodules should be monitored with particular care.

3. Lipid Disorders

Women who are being treated for hyperlipidemia should be followed closely if they elect to use oral contraceptives. Some progestogens may elevate LDL levels and may render the control of hyperlipidemias more difficult.

4. Liver Function

If jaundice develops in any woman receiving such drugs, the medication should be discontinued. Steroid hormones may be poorly metabolized in patients with impaired liver function.

5. Fluid Retention

Oral contraceptives may cause some degree of fluid retention. They should be prescribed with caution, and only with careful monitoring, in patients with conditions which might be aggravated by fluid retention.

6. Emotional Disorders

Women with a history of depression should be carefully observed and the drug discontinued if depression recurs to a serious degree.

7. Contact Lenses

Contact lens wearers who develop visual changes or changes in lens tolerance should be assessed by an ophthalmologist.

8. Drug Interactions

Effects of Other Drugs on Oral Contraceptives (78)

Rifampin: Metabolism of both norethindrone and ethinyl estradiol is increased by rifampin. A reduction in contraceptive effectiveness and increased incidence of breakthrough bleeding and menstrual irregularities have been associated with concomitant use of rifampin.

Anticonvulsants: Anticonvulsants such as phenobarbital, phenytoin, and carbamazepine, have been shown to increase the metabolism of ethinyl estradiol and/or norethindrone, which could result in a reduction in contraceptive effectiveness.

Troglitazone: Administration of troglitazone with an oral contraceptive containing ethinyl estradiol and norethindrone reduced the plasma concentrations of both by approximately 30%, which could result in a reduction of contraceptive effectiveness.

Antibiotics: Pregnancy while taking oral contraceptives has been reported when the oral contraceptives were administered with antimicrobials such as ampicillin, tetracycline, and griseofulvin. However, clinical pharmacokinetic studies have not demonstrated any consistent effect of antibiotics (other than rifampin) on plasma concentrations of synthetic steroids.

Atorvastatin: Coadministration of atorvastatin and an oral contraceptive increased AUC values for norethindrone and ethinyl estradiol by approximately 30% and 20%, respectively.

Concomitant Use with HCV Combination Therapy – Liver Enzyme Elevation Do not co-administer [DRUG] with HCV drug combinations containing ombitasvir/paritaprevir/ritonavir, with or without dasabuvir, due to potential for ALT elevations (see Warnings, RISK OF LIVER ENZYME ELEVATIONS WITHCONCOMITANT HEPATITIS C TREATMENT)

Others: Ascorbic acid and acetaminophen may increase plasma ethinyl estradiol concentrations, possibly by inhibition of conjugation. A reduction in contraceptive effectiveness and increased incidence of breakthrough bleeding has been suggested with phenylbutazone.

Effects of Oral Contraceptives on Other Drugs

Oral contraceptive combinations containing ethinyl estradiol may inhibit the metabolism of other compounds. Increased plasma concentrations of cyclosporine, prednisolone, and theophylline have been reported with concomitant administration of oral contraceptives. In addition, oral contraceptives may induce the conjugation of other compounds. Decreased plasma concentrations of acetaminophen and increased clearance of temazepam, salicylic acid, morphine, and clofibric acid have been noted when these drugs were administered with oral contraceptives.

9. Interactions with Laboratory Tests

Certain endocrine and liver function tests and blood components may be affected by oral contraceptives:

a. Increased prothrombin and factors VII, VIII, IX, and X; decreased antithrombin 3; increased norepinephrine-induced platelet aggregability.

b. Increased thyroid binding globulin (TBG) leading to increased circulating total thyroid hormone, as measured by protein-bound iodine (PBI), T4 by column or by radioimmunoassay. Free T3 resin uptake is decreased, reflecting the elevated TBG; free T4 concentration is unaltered.

c. Other binding proteins may be elevated in serum.

d. Sex-binding globulins are increased and result in elevated levels of total circulating sex steroids and corticoids; however, free or biologically active levels remain unchanged.

e. Triglycerides may be increased.

f. Glucose tolerance may be decreased.

g. Serum folate levels may be depressed by oral contraceptive therapy. This may be of clinical significance if a woman becomes pregnant shortly after discontinuing oral contraceptives.

10. Carcinogenesis

See WARNINGS section.

11. Pregnancy

Pregnancy Category X. See CONTRAINDICATIONS and WARNINGS sections.

12. Nursing Mothers

Small amounts of oral contraceptive steroids have been identified in the milk of nursing mothers, and a few adverse effects on the child have been reported, including jaundice and breast enlargement. In addition, oral contraceptives given in the postpartum period may interfere with lactation by decreasing the quantity and quality of breast milk. If possible, the nursing mother should be advised not to use oral contraceptives but to use other forms of contraception until she has completely weaned her child.

13. Pediatric Use

Safety and efficacy of norethindrone acetate and ethinyl estradiol tablets have been established in women of reproductive age. Safety and efficacy are expected to be the same for postpubertal adolescents under the age of 16 and for users 16 years and older. Use of this product before menarche is not indicated.


See patient labeling printed below.


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

● Thrombophlebitis

● 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, although additional confirmatory studies are needed:

● 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

● Rash (allergic)

● 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 the 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

● Budd-Chiari syndrome

● Acne

● Changes in libido

● Colitis


Serious ill effects have not been reported following acute ingestion of large doses of oral contraceptives by young children. Overdosage may cause nausea, and withdrawal bleeding may occur in females.


The following non-contraceptive health benefits related to the use of oral contraceptives are supported by epidemiological studies which largely utilized oral contraceptive formulations containing estrogen doses exceeding 0.035 mg of ethinyl estradiol or 0.05 mg of mestranol (79 to 84).

Effects on menses:

● Increased menstrual cycle regularity

● Decreased blood loss and decreased incidence of iron deficiency anemia

● Decreased incidence of dysmenorrhea

Effects related to inhibition of ovulation:

● Decreased incidence of functional ovarian cysts

● Decreased incidence of ectopic pregnancies

Effects from long-term use:

● Decreased incidence of fibroadenomas and fibrocystic disease of the breast

● Decreased incidence of acute pelvic inflammatory disease

● Decreased incidence of endometrial cancer

● Decreased incidence of ovarian cancer


The compact tablet dispenser has been designed to make oral contraceptive dosing as easy and as convenient as possible. The tablets are arranged in three rows of seven tablets each, with the days of the week appearing on the compact tablet dispenser above the first row of tablets.

Note: Each compact tablet dispenser has been preprinted with the days of the week, starting with Sunday, to facilitate a Sunday-Start regimen. Six different day label stickers have been provided with the Detailed Patient & Brief Summary Patient Package Insert in order to accommodate a Day-1 Start regimen. If the patient is using the Day-1 Start regimen, she should place the self-adhesive day label sticker that corresponds to her starting day over the preprinted days.

Important: The patient should be instructed to use an additional method of protection until after the first week of administration in the initial cycle when utilizing the Sunday-Start regimen.

The possibility of ovulation and conception prior to initiation of use should be considered.

Dosage and Administration for 21-Day Dosage Regimen

To achieve maximum contraceptive effectiveness, Microgestin 1/20 should be taken exactly as directed and at intervals not exceeding 24 hours. Microgestin 1/20 provides the patient with a convenient tablet schedule of “3 weeks on-1 week off”. Two dosage regimens are described, one of which may be more convenient or suitable than the other for an individual patient. For the initial cycle of therapy, the patient begins her tablets according to the Day 1 Start or Sunday-Start regimen. With either regimen, the patient takes one tablet daily for 21 consecutive days followed by one week of no tablets.

A. Sunday-Start Regimen: The patient begins taking tablets from the top row of the dispenser (labeled Sunday) on the first Sunday after menstrual flow begins. When the menstrual flow begins on Sunday, the first tablet is taken on the same day. The last tablet in the dispenser will be taken on a Saturday, followed by no tablets for a week (7 days). For all subsequent cycles, the patient then begins a new 21-tablet regimen on the eighth day, Sunday, after taking her last tablet. Following this regimen, of 21 days on-7 days off, the patient will start all subsequent cycles on a Sunday.

B. Day-1 Start Regimen: The first day of menstrual flow is Day 1. The patient places the self-adhesive day label sticker that corresponds to her starting day over the preprinted days on the tablet dispenser. She starts taking one tablet daily, beginning with the first tablet in the top row. The patient completes her 21-tablet regimen when she has taken the last tablet in the tablet dispenser. She will then take no tablets for a week (7 days). For all subsequent cycles, the patient begins a new 21-tablet regimen on the eighth day after taking her last tablet, again starting with the first tablet in the top row after placing the appropriate day label sticker over the preprinted days on the tablet dispenser. Following this regimen of 21 days on–7 days off, the patient will start all subsequent cycles on the same day of the week as the first course. Likewise, the interval of no tablets will always start on the same day of the week.

Tablets should be taken regularly with a meal or at bedtime. It should be stressed that efficacy of medication depends on strict adherence to the dosage schedule.

Special Notes on Administration

Menstruation usually begins two or three days, but may begin as late as the fourth or fifth day, after discontinuing medication. If spotting occurs while on the usual regimen of one tablet daily, the patient should continue medication without interruption.

If the patient forgets to take one or more tablets, the following is suggested:

One tablet is missed

● take tablet as soon as remembered

● take next tablet at the regular time

Two consecutive tablets are missed (week 1 or week 2)

● take two tablets as soon as remembered

● take two tablets the next day

● use another birth control method for seven days following the missed tablets

Two consecutive tablets are missed (week 3)

Sunday-Start Regimen:

● take one tablet daily until Sunday

● discard remaining tablets

● start new pack of tablets immediately (Sunday)

● use another birth control method for seven days following the missed tablets

Day-1 Start Regimen:

● discard remaining tablets

● start new pack of tablets that same day

● use another birth control method for seven days following the missed tablets

Three (or more) consecutive tablets are missed

Sunday-Start Regimen:

● take one tablet daily until Sunday

● discard remaining tablets

● start new pack of tablets immediately (Sunday)

● use another birth control method for seven days following the missed tablets

Day-1 Start Regimen:

● discard remaining tablets

● start new pack of tablets that same day

● use another birth control method for seven days following the missed tablets

The possibility of ovulation occurring increases with each successive day that scheduled pale yellow tablets are missed. While there is little likelihood of ovulation occurring if only one pale yellow tablet is missed, the possibility of spotting or bleeding is increased. This is particularly likely to occur if two or more consecutive pale yellow tablets are missed.

In the rare case of bleeding which resembles menstruation, the patient should be advised to discontinue medication and then begin taking tablets from a new compact tablet dispenser on the next Sunday or the first day (Day-1), depending on her regimen. Persistent bleeding which is not controlled by this method indicates the need for reexamination of the patient, at which time nonfunctional causes should be considered.

Use of Oral Contraceptives in the Event of a Missed Menstrual Period

1. If the patient has not adhered to the prescribed dosage regimen, the possibility of pregnancy should be considered after the first missed period and oral contraceptives should be withheld until pregnancy has been ruled out.

2. If the patient has adhered to the prescribed regimen and misses two consecutive periods, pregnancy should be ruled out before continuing the contraceptive regimen.

After several months on treatment, bleeding may be reduced to a point of virtual absence. This reduced flow may occur as a result of medication, in which event it is not indicative of pregnancy. provides trustworthy package insert and label information about marketed prescription drugs as submitted by manufacturers to the U.S. Food and Drug Administration. Package information is not reviewed or updated separately by Every individual prescription drug label and package insert entry contains a unique identifier which can be used to secure further details directly from the U.S. National Institutes of Health and/or the FDA.

Medication Sections

Medication Information by RSS

As a leading independent provider of trustworthy medication information, we source our database directly from the FDA's central repository of drug labels and package inserts under the Structured Product Labeling standard. provides the full prescription-only subset of the FDA's repository. Medication information provided here is not intended as a substitute for direct consultation with a qualified health professional.

Terms of Use | Copyright © 2020. All Rights Reserved.