INFORMATION FOR HEALTH PROFESSIONALS
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The sponsor (pharmaceutical company) of this product has
advised Medsafe that this product has either been discontinued or is no longer
marketed in New Zealand.
Therefore this Data Sheet may not be up to date.
Medsafe has elected to leave it on this web site because supplies of this
product may still be available, and health professionals should continue to
have access to this product information in the interim.
You may be able to find a more current Data Sheet containing the same medicine
by returning to the main Data Sheet page and searching by ingredient name.
Each round white tablet contains 750 micrograms of levonorgestrel.
The precise mode of action of POSTINOR-2 is not known. At the recommended regimen, levonorgestrel is thought to work mainly by preventing ovulation and fertilisation if the intercourse has taken place in the preovulatory phase, when the likelihood of fertilisation is the highest. POSTINOR-2 may also cause endometrial changes that discourage implantation. POSTINOR-2 is not effective once the process of implantation has begun.
At the recommended regimen, levonorgestrel is not expected to induce significant modification of blood clotting factors, and lipid and carbohydrate metabolism.
It has been estimated that POSTINOR-2 prevents 85% of expected pregnancies. Efficacy appears to decline with time after intercourse (95% within 24 hours, 85% if used between 24 and 48 hours and/or 58% if used between 48 and 72 hours). Efficacy after 72 hours is unknown.
Orally administered levonorgestrel is rapidly and almost completely absorbed. Following ingestion of one tablet of POSTINOR-2, maximum drug serum levels of 14.1 ng/ml were found at 1.6 hours. Thereafter, levonorgestrel serum levels decrease in two disposition phases with mean elimination half-lives which range from about 9 hours to 14.5 hours. Levonorgestrel is not excreted in unchanged form but as metabolites. Levonorgestrel metabolites are excreted in about equal proportions with urine and faeces. The biotransformation follows the known pathways of steroid metabolism; levonorgestrel is hydroxylated in the liver and the metabolites are excreted as glucuronide conjugates. No pharmacologically active metabolites are known.
Levonorgestrel is bound to serum albumin and sex hormone binding globulin (SHBG). Only about 1.5% of the total serum levels are present as free steroid, but 65% are specifically bound to SHBG. The absolute bioavailability of levonorgestrel was determined to be almost 100% of the dose administered.
About 0.1% of the maternal dose can be transferred via milk to the nursed infant.
POSTINOR-2 is an oral emergency contraceptive indicated for use within 72 hours of unprotected intercourse. It should be used only as an emergency measure.
Women who present for repeated courses of emergency contraception should be advised to consider long-term methods of contraception.
The treatment requires two tablets to be taken. One tablet is taken as soon as possible (and not later than 72 hours) after unprotected intercourse. The second tablet should be taken 12 hours (and no later than 16 hours) after the first tablet.
If the patient vomits within three hours of taking either tablet another tablet should be taken immediately.
POSTINOR-2 can be used at any time during the menstrual cycle unless menstrual bleeding is overdue.
After using emergency contraception it is recommended to use a local barrier method (condom, cervical cap) until the next menstrual period starts. The use of POSTINOR-2 does not contraindicate the continuation of regular hormonal contraception.
POSTINOR-2 is not recommended in children. Very limited data are available in women under 16 years of age.
POSTINOR-2 should not be given to pregnant women. If menstrual bleeding is overdue, if the last menstrual period was abnormal in timing or character, or if pregnancy is suspected for any other reason, pregnancy should be excluded (by pregnancy testing or pelvic examination) before treatment is given.
Hypersensitivity to the active substance levonorgestrel or any of the excipients.
Emergency contraception is an occasional method. POSTINOR-2 is not as effective as a conventional regular method of contraception and is suitable only as an emergency measure. It should not replace a regular contraceptive method.
Emergency contraception does not prevent a pregnancy in every instance. If there is uncertainty about the timing of the unprotected intercourse or if the woman has had unprotected intercourse more than 72 hours earlier in the same menstrual cycle, conception may have occurred. Treatment with POSTINOR-2 following a second act of intercourse may therefore be ineffective in preventing pregnancy. If menstrual periods are delayed by more than 5 days or abnormal bleeding occurs at the expected date of menstrual periods or pregnancy is suspected for any other reason, pregnancy should be excluded.
If pregnancy occurs after treatment with POSTINOR-2, the possibility of an ectopic pregnancy should be considered.
After taking POSTINOR-2, menstrual periods are usually normal and occur at the expected date. They can sometimes occur earlier or later than expected by a few days. It is recommended to make a medical appointment to initiate or adapt a method of regular contraception. In case no menstrual period occurs in the next pill-free period following the use of POSTINOR-2 after regular hormonal contraception, pregnancy should be ruled out.
Repeated administration within a menstrual cycle is not advisable because of the possibility of disturbance of the cycle. Women who present for repeated courses of emergency contraception should be advised to consider long-term methods of contraception.
The use of emergency contraception does not replace the necessary precautions against sexually transmitted diseases.
POSTINOR-2 is not recommended in patients with severe hepatic dysfunction. Severe malabsorption syndromes, such as Crohn's disease, might impair the efficacy of POSTINOR-2.
Conditions which are considered relative contraindications include severe hypertension (BP>180+/110+), diabetes mellitus with nephropathy, retinopathy, neuropathy or vascular disease, ischaemic heart disease, stroke, or a past history of breast cancer. However, since exposure to levonorgestrel with POSTINOR-2 is brief, the risks of pregnancy in all women, including those with pre-existing medical conditions, are almost certainly greater than those associated with POSTINOR-2.
No effect is known.
Levonorgestrel is a well-established progestogen with anti-estrogenic activity. The safety profile following systemic administration is well documented and reveals no special concerns for use beyond that already listed in this text.
In acute toxicity studies performed in mice and rats levonorgestrel induced a decrease of body weight and dermatitis-like (non-irritative or non-allergic) changes on the skin. In repeat dose toxicity studies performed in mice, rats and rabbits, there were no overt signs of toxicity and no target organs or functions were identified other than the reproductive system.
POSTINOR-2 should not be given to pregnant women and it will not interrupt the pregnancy. In the case of failure of emergency contraception, epidemiological studies indicate no adverse effects of progestogens on the fetus. It is generally considered that known teratogens will not produce malformations before organogenesis starts, which is later than 72 hours after fertilisation.
Levonorgestrel is secreted into breast milk. The potential exposure of an infant to levonorgestrel can be reduced if the breastfeeding woman takes the tablets immediately after feeding and avoids nursing following each POSTINOR-2 administration.
The following table gives the frequency of undesirable effects:
| Effect | Percent of women with effect |
|---|---|
| (n=977 women)* | |
| Nausea | 23.1 |
| Low abdominal pain | 17.6 |
| Fatigue | 16.9 |
| Headache | 16.8 |
| Dizziness | 11.2 |
| Breast tenderness | 10.8 |
| Vomiting | 5.6 |
| All other undesirable effects ** | 13.5 |
* Lancet, 1998, 352, 428-433;
** Mostly diarrhoea, irregular bleeding and spotting
Bleeding patterns may be temporarily disturbed, but most women will have their next menstrual period at the expected time.
If the next menstrual period is more than 5 days overdue, pregnancy should be excluded.
The metabolism of levonorgestrel is enhanced by concomitant use of liver enzyme inducers. Drugs suspected of having the capacity to reduce the efficacy of levonorgestrel-containing medication includes: barbiturates, primidone, phenytoin, carbamazepine, herbal medicines containing Hypericum perforatum (St Johns' Wort), rifampicin, ritonavir, rifabutin and griseofulvin.
Medicines containing levonorgestrel may increase the risk of cyclosporin toxicity due to possible inhibition of cyclosporin metabolism.
Serious undesirable effects have not been reported following acute ingestion of large doses of oral contraceptives. Overdose may cause nausea, and withdrawal bleeding may occur. There are no specific antidotes and treatment should be symptomatic.
Shelf-life: 5 years
Special precautions for storage: Store below 25°C
Pharmacist Only Medicine
POSTINOR-2 contains one blister aluminium/PVC blister sheet containing two tablets.
Potato starch, maize starch, colloidal silica anhydrous, magnesium stearate, talc, lactose monohydrate.
Keep out of reach of children.
Rex Medical Ltd
PO Box 18-119
Glen Innes
AUCKLAND.
Telephone: (09) 574 6060
Bayer New Zealand Limited
3 Argus Place
Hillcrest
North Shore
AUCKLAND 0627
Freephone: 0800 233 988
28 June 2007