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

• 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
• 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
• Acne
• Changes in libido
• Colitis
• Budd-Chiari Syndrome

Read the Viorele (deogestrel and ethinyl estradiol tablets) Side Effects Center for a complete guide to possible side effects »

Reduced efficacy and increased incidence of breakthrough bleeding and menstrual irregularities have been associated with concomitant use of rifampin. A similar association, though less marked, has been suggested with barbiturates, phenylbutazone, phenytoin sodium, carbamazepine and possibly with griseofulvin, ampicillin, and tetracyclines (72).

Combination OCs have been shown to significantly decrease plasma concentrations of lamotrigine likely due to induction of lamotrigine glucuronidation. This may reduce seizure control; therefore, dosage adjustments of lamotrigine may be necessary. Consult the labeling of the concurrently-used drug to obtain further information about interactions with COCs or the potential for enzyme alterations.

Interactions With Laboratory Tests

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

1. Increased prothrombin and factors VII, VIII, IX and X; decreased antithrombin 3; increased norepinephrine-induced platelet aggregability.
2. 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.
3. Other binding proteins may be elevated in serum.
4. Sex hormone-binding globulins are increased and result in elevated levels of total circulating sex steroids; however, free or biologically active levels either decrease or remain unchanged.
5. High-density lipoprotein cholesterol (HDL-C) and triglycerides may be increased, while low-density lipoprotein cholesterol (LDL-C) and total cholesterol (Total-C) may be decreased or unchanged.
6. Glucose tolerance may be decreased.
7. 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.

REFERENCES

72. Stockley I. Interactions with oral contraceptives. J Pharm 1976; 216:140-143.

Last reviewed on RxList: 6/1/2012
This monograph has been modified to include the generic and brand name in many instances.