Norinyl-1
Norinyl-1 is a birth control pill known as a combined contraceptive pill. Oral combined contraceptives contain two versions of the sex hormones present in women. The natural forms of these hormones are oestrogen and progesterone. Norinyl-1, developed by Pfizer - uses mestranol and norethisterone, which are synthetic versions of the hormones.
How Does Norinyl-1 Work?
The levels of a woman's hormones change throughout the course of her menstrual cycle. Changes in hormones signal the ovaries to release an egg and prepare the uterus to receive a fertilised egg. Norinyl-1 and similar contraceptives interrupt the normal cycle by sending a false signal to the ovaries that indicates an egg has already been released. This effectively stops ovulation from occurring, thereby preventing pregnancy.
Norinyl-1 Dosage
Each Norinyl-1 tablet contains 1 milligram of norethisterone and 50 micrograms of mestranol as active ingredients. The pill is available as a 28-day pack, which contains seven pills with no active ingredients, or as a 21-day pack, which contains only pills with active ingredients.
How Often is Norinyl-1 Taken?
Patients take one tablet each day. If receiving the 21-day pack, no tablets are taken for the seven days following the 21st day; after seven days, the patient starts a new pack. If receiving the 28-day pack, the patient takes the active tablets for 21 days and then takes the seven inactive pills, after which she begins a new pack.
How Effective is Norinyl-1?
Studies show that out of every 1,000 women taking Norinyl-1, two will become pregnant. This equates to an effective rate of 99.8 percent. However, to achieve maximum effectiveness, women should take any oral contraceptive precisely as ordered and should be aware of other medications and illnesses that may reduce the drug's effectiveness.
Norinyl-1 Side Effects
Many women who take oral contraceptives experience no adverse reactions, some have mild side effects and a few may have reactions that are quite severe. The most common side effects experienced by women taking Norinyl-1 include stomach problems, including nausea and vomiting; tender or swollen breasts; water retention; mild headaches; and light menstrual bleeding or spotting between periods. Some women have developed vaginal yeast infections; patches of brown skin, primarily on the face; reduced sex drive; discomfort when wearing contact lenses; and depression. Norinyl-1 and similar medications may increase blood pressure, and some patients have developed gallstones and liver problems. All oral contraceptives increase a woman's risk of blood clots, which in turn increases her risk of heart attack or stroke.
What Other Medications Affect Norinyl-1?
Patients need to tell their doctors about any medicines, herbal supplements or vitamins they are taking before they begin taking Norinyl-1. Once they are taking the pill, they should inform their doctors of that fact any time they are prescribed a new medication. Certain drugs can make Norinyl-1 less effective. These include barbiturates, such as phenobarbital; carbamazepine; modafinil; nevirapine; oxcarbazepine; phenytoin; primidone; rifampicin; rifabutin; ritonavir; and topiramate. Women taking selegiline should not take Norinyl-1, and those taking theophylline may need to ask their doctors if their dosage needs to be adjusted. Even drugs that do not require a prescription may interact with Noriyl-1. For example, women taking oral contraceptives should not take St. John's wort as it may reduce the effectiveness of the contraceptive. Norinyl-1 may also increase the effects of certain drugs and supplements, such as melatonin, tacrolimus, tizanidine and voriconazole.
Who Should Not Take Norinyl-1
Women should not take Norinyl-1 if they are pregnant or suspect they might be pregnant. Norinyl-1 may reduce a woman's supply of breast milk, so women are typically advised to avoid the pill until the child is weaned. Women who have had a stroke or heart attack should not take combined oral contraceptives. Patients with angina, a defective heart valve, atrial fibrillation, high cholesterol or severe diabetes should avoid Norinyl-1. Women who are over 50 or who smoke 40 or more cigarettes daily should not take Norinyl-1. High blood pressure that is rated moderate to severe typically disqualifies patients from receiving Norinyl-1 prescriptions. Women with cancer, liver disease or gallstones should not take the pill.
