"What are birth control pills and how do they work?
Birth control pills are also known as oral contraceptives (OCs) or, simply, “the pill.” They offer protection against pregnancy by blocking the union of sperm and egg, thereby prevent"...
Loestrin 24 Fe
The most common adverse events reported by 2 - 6% of the 743 women using Loestrin 24 Fe were the following, in order of decreasing incidence: headache, vaginal candidiasis, upper respiratory infection, nausea, menstrual cramps, breast tenderness, sinusitis, vaginitis (bacterial), abnormal cervical smear, acne, urinary tract infection, mood swings, weight gain, vomiting, and metrorrhagia.
Among the 743 women using Loestrin 24 Fe (norethindrone acetate and ethinyl estradiol) , 46 women (6.2%) withdrew because of an adverse event. Adverse events occurring in 3 or more subjects leading to discontinuation of treatment were, in decreasing order: abnormal bleeding (0.9%), nausea (0.8%), menstrual cramps (0.4%), increased blood pressure (0.4%), and irregular bleeding (0.4%).
An increased risk of the following serious adverse reactions has been associated with the use of oral contraceptives (see WARNINGS section):
- Arterial thromboembolism
- Pulmonary embolism
- Myocardial infarction
- Cerebral hemorrhage
- Cerebral thrombosis
- 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:
- Gastrointestinal symptoms (such as abdominal pain, cramps and bloating)
- Breakthrough bleeding
- Change in menstrual flow
- Temporary infertility after discontinuation of treatment
- Edema/fluid retention
- Melasma/chloasma which may persist
- Breast changes: tenderness, pain, enlargement, and secretion
- Change in weight or appetite (increase or decrease)
- Change in cervical ectropion and secretion
- Possible diminution in lactation when given immediately postpartum
- Cholestatic jaundice
- Migraine headache
- Rash (allergic)
- Mood changes, including depression
- Vaginitis, including candidiasis
- Change in corneal curvature (steepening)
- Intolerance to contact lenses
- Decrease in serum folate levels
- Exacerbation of systemic lupus erythematosus
- Exacerbation of porphyria
- Exacerbation of chorea
- Aggravation of varicose veins
- Anaphylactic/anaphylactoid reactions, including urticaria, angioedema, and severe reactions with respiratory and circulatory symptoms
The following adverse reactions have been reported in users of oral contraceptives, and a causal association has been neither confirmed nor refuted:
- Budd-Chiari syndrome
- Changes in libido
- Cystitis-like syndrome
- Erythema multiforme
- Erythema nodosum
- Hemorrhagic eruption
- Hemolytic uremic syndrome
- Impaired renal function
- Loss of scalp hair
- Optic neuritis, which may lead to partial or complete loss of vision
- Premenstrual syndrome
Read the Loestrin 24 Fe (norethindrone acetate and ethinyl estradiol) Side Effects Center for a complete guide to possible side effects
Changes in contraceptive effectiveness associated with co-administration of other products
Anti-infective agents and anticonvulsants
Contraceptive effectiveness may be reduced when hormonal contraceptives are co-administered with antibiotics, anticonvulsants, and other drugs that increase the metabolism of contraceptive steroids. This could result in unintended pregnancy or breakthrough bleeding. Examples include rifampin, barbiturates, phenylbutazone, phenytoin, carbamazepine, felbamate, oxcarbazepine, topiramate, and griseofulvin.
Anti-HIV protease inhibitors
Several of the anti-HIV protease inhibitors have been studied with co-administration of oral combination hormonal contraceptives; significant changes (increase and decrease) in the plasma levels of the estrogen and progestin have been noted in some cases. The safety and efficacy of combination oral contraceptive products may be affected with co-administration of anti-HIV protease inhibitors. Healthcare providers should refer to the label of the individual anti-HIV protease inhibitors for further drug-drug interaction information.
Herbal products containing St. John's Wort (hypericum perforatum) may induce hepatic enzymes (cytochrome P450) and p-glycoprotein transporter and may reduce the effectiveness of contraceptive steroids. This may also result in breakthrough bleeding.
Increase in plasma levels of estradiol associated with co-administered drugs
Co-administration of atorvastatin and certain combination oral contraceptives containing ethinyl estradiol increase AUC values for ethinyl estradiol by approximately 20%. Ascorbic acid and acetaminophen may increase plasma ethinyl estradiol levels, possibly by inhibition of conjugation. CYP3A4 inhibitors such as itraconazole or ketoconazole may increase plasma hormone levels.
Changes in plasma levels of co-administered drugs:
Combination hormonal contraceptives containing some synthetic estrogens (e.g., ethinyl estradiol) may inhibit the metabolism of other compounds. Increased plasma concentrations of cyclosporine, prednisolone, and theophylline have been reported with concomitant administration of combination oral contraceptives. Decreased plasma concentrations of acetaminophen and increased clearance of temazepam, salicylic acid, morphine and clofibric acid, due to induction of conjugation have been noted when these drugs were administered with combination oral contraceptives.
Interactions With Laboratory Tests
Certain endocrine and liver function tests and blood components may be affected by oral contraceptives:
- Increased prothrombin and factors VII, VIII, IX, and X; decreased antithrombin 3; increased norepinephrine-induced platelet aggregability.
- 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.
- Other binding proteins may be elevated in serum.
- Sex hormone binding globulins are increased and result in elevated levels of total circulating sex steroids and corticoids; however, free or biologically active levels remain unchanged.
- Triglycerides may be increased and levels of various other lipids and lipoproteins may be affected.
- Glucose tolerance may be decreased.
- 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.
Read the Loestrin 24 Fe Drug Interactions Center for a complete guide to possible interactions
Last reviewed on RxList: 9/18/2008
This monograph has been modified to include the generic and brand name in many instances.
Additional Loestrin 24 Fe Information
Loestrin 24 Fe - User Reviews
Loestrin 24 Fe User Reviews
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