Drug Class Description
Progestogens.

Generic Name
Norethisterone

Drug Description
Each tablet contains norethisterone 0.35 mg.

Presentation
Small, round, white tablet, engraved C035 on both faces.

Indications
Oral contraception.

Adult Dosage
For oral administration.Adults:Tablet intake from the first pack is started on the first day of menstruation; no extra contraceptive precautions are necessary.One tablet is taken at the same time each day, every day of the year, whether menstruation occurs or not.

Contra Indications
• Existing thrombophlebitis• Existing thrombo-embolic disorders• Cerebrovascular disease or a past history of this condition• Myocardial infarction or a past history of this condition• Markedly impaired liver function• Known or suspected hormone dependent neoplasia• Known or suspected carcinoma of the breast• Undiagnosed abnormal genital tract bleeding• Known or suspected pregnancy• Cholestatic jaundice of pregnancy or jaundice with prior pill use• Hepatic adenomas or carcinomas

Special Precautions
There is a general opinion, based on statistic evidence, that users of combined oral contraceptives (ie oestrogen plus progestogen) experience more often than non-users various disorders of the circulation of blood, including strokes (blood clots in, and haemorrhages from, the blood vessels of the brain), heart attacks (coronary thromboses) and blood clots obstructing the arteries of the lungs (pulmonary emboli). There may not be a full recovery from such disorders and it should be realised that in a few cases they may be fatal.To date no association between these disorders and progestogen-only oral contraceptives (such as Micronor Oral Contraceptive Tablets) has been shown. However there is a risk that the users of such progestogen only oral contraceptives will (like users of the combined oral contraceptive) be exposed to an increased risk of suffering from these disorders.Reasons for stopping oral contraceptives immediately• Early manifestations of thrombotic or thrombo-embolic disorders, thrombophlebitis• Cerebrovascular disorders (including haemorrhage)• Myocardial infarction• Pulmonary embolism• Gradual or sudden, partial or complete loss of vision• Proptosis or diplopia• Onset or aggravation of migraine or development of headaches of a new pattern which are recurrent, persistent or severe• Papilloedema or any evidence of retinal vascular lesions• During periods of immobility (eg after accidents)• Pregnancy• Manifestations of liver tumoursAssessment of women prior to starting oral contraceptives (and at regular intervals thereafter) should include a personal and family medical history of each woman. Physical examination should be guided by this and by the contra-indications (Section 4.3) and warnings (Section 4.4) for this product. The frequency and nature of these assessments should be based upon relevant guidelines and should be adapted to the individual woman, but should include measurement of blood pressure and, if judged appropriate by the clinician, breast, abdominal and pelvic examination including cervical cytology.Because of a possible increased risk of post surgery thrombo-embolic complications in oral contraceptive users, therapy should be discontinued six weeks prior to elective surgery.When Micronor is administered during the post-partum period, the increased risk of thrombo-embolic disease associated with the post-partum period must be considered.The following are some of the medical conditions reported to be influenced by the combined pill, and may be affected by Micronor. The physician will have to exercise medical judgement to commence, continue or discontinue therapy as appropriate. The worsening or first appearance of any of these conditions may indicate that Micronor should be discontinued.1. Pre-existing uterine fibromyomata may increase in size.2. A decrease in glucose tolerance in a significant number of women.3. An increase in blood pressure in a small but significant number of women.4. Cholestatic jaundice. Patients with a history of cholestatic jaundice of pregnancy are more likely to develop cholestatic jaundice during oral contraceptive therapy.5. Amenorrhoea during and after oral contraceptive therapy. Temporary infertility after discontinuation of treatment.6. Depression.7. Fluid retention. Conditions which might be influenced by this factor including epilepsy, migraine, asthma, cardiac or renal dysfunction.8. Varicose veins.9. Multiple sclerosis.10. Porphyria.11. Tetany.12. Intolerance to contact lenses.Or any condition that is prone to worsening during pregnancy.Ectopic pregnancyPregnancies in progestogen-only pill (POP) users are more likely to be ectopic than are pregnancies occurring in the general population, since POPs offer less protection against ectopic pregnancy than against intra-uterine pregnancy.Changing from another oral contraceptiveStart Micronor on the day following completion of the previous oral contraceptive pack without a break (or, in the case of the ED pill, omitting the inactive pills). No extra contraceptive precautions are required.Post-partum administrationMicronor can be started on the 21st day after childbirth. This will ensure the patient is protected immediately. If there is any delay in taking the first dose, contraception may not be established until 7 days after the first tablet has been taken. In these circumstances, patients should be advised that extra contraceptive precautions (non-hormonal methods) are necessary.After miscarriage or abortionPatients can take Micronor on the day after miscarriage or abortion, in which case no additional contraceptive precautions are required.Missed tabletsIf a tablet is missed within 3 hours of the correct dosage time, then the missed tablet should be taken as soon as possible; this will ensure that contraceptive protection is maintained. If one (for longer than 3 hours) or more tablets are missed, it is recommended that the patient takes the last missed tablet as soon as possible and continues to take the rest of the tablets as usual. Additional means of contraception (non-hormonal) should be used for the next seven days.If the patient does not have a period within 45 days of her last period, Micronor should be discontinued and pregnancy should be excluded.Vomiting and diarrhoeaAdditional contraceptive measures (non-hormonal) should be employed during the period of gastro-intestinal upset and for the next seven days.Laboratory testsThe following laboratory determinations may be altered in patients using oral contraceptives.Hepatic: increased BSP retention and other tests.Coagulation: increased prothrombin, factors VII, VIII, IX and X, decreased antithrombin III, increased platelet aggregability.Endocrine: increased PBI and butanol extractable protein-bound iodine and decreased T3 uptake, increased blood glucose levels.Other: increased phospholipids and triglycerides, decreased serum folate values and disturbance in tryptophan metabolism, decreased pregnanediol excretion, reduced response to metapyrone test.These tests usually return to pre-therapy values after discontinuing oral contraceptive use. However, the physician should be aware that these altered determinations may mask an underlying disease.

Interactions
Reduced efficacy and increased incidence of breakthrough bleeding have been associated with concomitant use of oral contraceptives and rifampicin. A similar association has been suggested with oral contraceptives and barbiturates, phenytoin sodium, ampicillin, tetracyclines and griseofulvin.The herbal remedy St John's wort (Hypericum perforatum) should not be taken concomitantly with this medicine as this could potentially lead to a loss of contraceptive effect.

Adverse Reactions
Side effects are usually self-limiting and of relatively short duration. Amongst the symptoms reported are:• Headaches/migraine• Nausea• Vomiting• Breast changes• Change in weight• Changes in libido• Chloasma• Breakthrough bleeding and spotting• Rash• Depression• Irregular cycle length (particularly in early cycles of therapy). It is important that patients should be advised that whilst on Micronor therapy they may experience that variation in cycle length and that they should continue taking a tablet every day whether they have a period or not. However, patients should be advised to discontinue Micronor and to consult their doctor if they have gone 45 days without having a period.Malignant hepatic tumours have been reported on rare occasions in long-term users of oral contraceptives. Benign hepatic tumours have also been associated with oral contraceptive use. A hepatic tumour should be considered in the differential diagnosis when upper abdominal pain, enlarged liver or signs of intra-abdominal haemorrhage occur.A meta-analysis from 54 epidemiological studies reported that there is a slightly increased relative risk of having breast cancer diagnosed in women who are currently using oral contraceptives (OCs). The observed pattern of increased risk may be due to an earlier diagnosis of breast cancer in OC users, the biological effects of OCs or a combination of both. The additional breast cancers diagnosed in current users of OCs or in women who have used OCs in the last 10 years are more likely to be localised to the breast than those in women who have never used OCs.Breast cancer is rare among women under 40 years of age whether or not they take OCs. Whilst the background risk increases with age, the excess number of breast cancer diagnoses in current and recent progesterone-only pill (POP) users is small in relation to the overall risk of breast cancer, possibly of similar magnitude to that associated with combined OCs. However, for POPs, the evidence is based on much smaller populations of users and so is less conclusive than that for combined OCs.The most important risk factor for breast cancer in POP users is the age women discontinue the POP; the older the age at stopping, the more breast cancers are diagnosed. Duration of use is less important and the excess risk gradually disappears during the course of the 10 years after stopping POP use, such that by 10 years there appears to be no excess.The evidence suggests that compared with never-users, among 10,000 women who use POPs for up to five years but stop by age 20, there would be much less than one extra case of breast cancer diagnosed up to 10 years afterwards. For those stopping by age 30 after 5 years use of the POP, there would be an estimated 2-3 extra cases (additional to the 44 cases of breast cancer per 10,000 women in this age group never exposed to oral contraceptives). For those stopping by age 40 after 5 years use, there would be an estimated 10 extra cases diagnosed up to 10 years afterwards (additional to the 160 cases of breast cancer per 10,000 never-exposed women in this age group).It is important to inform patients that users of all contraceptive pills appear to have a small increase in the risk of being diagnosed with breast cancer, compared with non-users of oral contraceptives, but that this has to be weighed against the known benefits.

Manufacturer
Janssen-Cilag

Drug Availability
(POM)

Updated
26 June 2009