Products
Oral contraceptives are commercially available in the form of film-coated tablets and coated tablets. Numerous products with different active ingredients are available from different manufacturers.
Structure and properties
Oral contraceptives usually contain an estrogen (mainly ethinyl estradiol, sometimes estradiol) and a progestin. Preparations are also available that contain only a progestin (minipill, e.g., desogestrel, norethisterone acetate). Progestins used include:
- Chlormadinone acetate
- Desogestrel
- Dienogest
- Drospirenone
- Gestodene
- Levonorgestrel
- Nomegestrol acetate
- Norethisterone acetate
- Norgestimate
Division
Oral contraceptives can be classified according to various criteria:
- Ingredients: estrogen-progestin combinations, progestin monopreparations, “natural” estrogens (e.g., Qlaira).
- Micropill: low-dose estrogen-progestin combination.
- Single-phase or multiphase preparations: in multiphase preparations, the concentration of active ingredients is adjusted to the cycle. So there is not always the same amount of active ingredients in the tablets. One speaks of one-, two-, three- or four-phase contraceptives.
- Minipills contain only a progestogen and no estrogen. They are indicated during breastfeeding and estrogen intolerance.
- Classification according to the generation of the progestogen (1st, 2nd, 3rd generation).
- Antiandrogens: the progestin in some pills has antiandrogenic properties, for example, cyproterone acetate or drospirenone.
- The morning-after pill can also be counted among the birth control pills, but has different properties and is administered only as a single dose.
- Duration of use: eg 21 days, continuously, with or without placebo tablets.
- Reliability: Pearl index
Effects
Oral contraceptives (ATC G03A) have contraceptive properties. The effects are primarily due to inhibition of ovulation. Other mechanisms involved include alteration of cervical mucus and the endometrium. This makes it more difficult for sperm to penetrate and for the egg to implant in the mucosa. Some progestins have additional antiandrogenic properties.
Indications
For peroral hormonal contraception. Some drugs containing progestins with antiandrogenic properties are additionally approved for the treatment of androgenization symptoms in women (e.g., cyproterone acetate). Other possible indications include menstrual cramps, premenstrual syndrome, and endometriosis (off-label).
Dosage
According to the SmPC. Usually one tablet is taken at the same time each day for 21 consecutive days, followed by a week’s rest. Start on the first day of menstruation. However, depending on the product, alternative dosing schedules also exist.
Contraindications
Numerous precautions must be observed when taking hormonal contraceptives. They can be found in the drug label.
Interactions
Many estrogens and progestins are metabolized by CYP3A4 and other CYP450s. CYP inducers, such as rifampicin or St. John’s wort, may decrease protection and lead to unintended pregnancy. Other interactions are possible with antibiotics.
Adverse effects
The most common possible adverse effects include bleeding; headache; digestive problems such as nausea, vomiting, and diarrhea; breast tenderness; fluid retention; weight gain; mood changes; and vaginitis. Hormonal contraceptives increase the risk of thromboembolic conditions such as heart attack, stroke, venous thrombosis, and pulmonary embolism. However, such incidents are very rare.
