SELECTOR (Levonorgestrel) also known as Dexnorgestrel, is an emergency contraceptive. It is intended to prevent pregnancy after known or suspected contraceptive failure or unprotected intercourse. Levonorgestrel emergency contraceptive will not terminate a pregnancy that has already begun (the fertilized egg has attached to the uterus). Chemically, levonorgestrel is 13ß-ethyl-17ßhydroxy-18,19-dinor-17a-pregn-4-en-20-yn-3-one. Its molecular formula is C₂₁H₂₈O₂ and its molecular weight is 312.5.

STRUCTURAL FORMULA :
Its structural formula is :

COMPOSITION :
Each film coated tablet contains :
Levonorgestrel B.P. 0.750 mg
Excipients q.s.

Colour : Titanium dioxide B.P.

ACTIONS :
The precise mode of action of levonorgestrel is not known, but 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. Levonorgestrel may also cause endometrial changes that discourage implantation. Levonorgestrel is not effective once the process of implantation has begun. Levonorgestrel emergency contraceptive is not intended for use as a routine form of birth control and should not be used in this manner. At recommended regimen, levonorgestrel is not expected to induce significant modification of blood clotting factors and lipid and carbohydrate metabolism.

PHARMACOKINETICS :
Levonorgestrel is rapidly and almost completely absorbed after a dose by mouth, and undergoes little first-pass hepatic metabolism. It is highly bound to plasma proteins; 42 to 68 % to sex hormone binding globulin (SHBG) and 30 to 56 % to serum albumin. The proportion bound to sex hormone binding globulin is higher when it is given with an oestrogen. Levonorgestrel is not excreted in unchanged form but as metabolites and is metabolised in the liver to sulphate and glucuronide conjugates, which are excreted in the urine and to a lesser extent in the faeces. No pharmacologically active metabolites are known. Levonorgestrel is distributed into breast milk.

INDICATIONS :
It 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.

Administration :
For oral use as an emergency contraceptive.

Dosage :
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 3 hours of taking either tablet another tablet should be taken immediately. SELECTOR 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 SELECTOR does not contraindicate the continuation of regular hormonal contraception. SELECTOR is not recommended in children.

CONTRAINDICATIONS :
SELECTOR 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.

WARNINGS :
Emergency contraception is an occasional method. SELECTOR 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.

PRECAUTIONS :
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 SELECTOR, the possibility of an ectopic pregnancy should be considered. After taking SELECTOR, 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 SELECTOR 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. SELECTOR is not recommended in patients with severe hepatic dysfunction. Severe malabsorption syndromes, such as Crohns disease, might impair the efficacy of SELECTOR.

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 SELECTOR is brief, the risks of pregnancy in all women, including those with pre-existing medical conditions, are almost certainly greater than those associated with SELECTOR.

Pregnancy :
SELECTOR should not be given to pregnant women and it will not interrupt the pregnancy. However, many epidemiological studies have failed to show any association between foetal malformations and oral contraceptives, even when used inadvertently during pregnancy.

Lactation :
Levonorgestrel was detected in breast milk and the circulation of breast-fed infants during the use of oral contraceptive. A review of studies of a levonorgestrel tablets used during lactation concluded that it was generally shown to have no adverse effect on the duration of 
lactation, infant growth or development. The American Academy of Paediatrics considers that levonorgestrel is usually compatible with breast feeding. Progestogen-only contraceptives should not be started until several weeks after birth if the woman is breast feeding.

INTERACTION :
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.

SIDE EFFECTS :
The following table gives the frequency of undesirable effects :
Effects Percent of women with effect (n = 997 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, 1988, 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.

OVERDOSAGE AND TREATMENT :
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.

STORAGE :
Store below 30°C (86°F), protected from moisture and light.
Do not refrigerate.

SHELF LIFE :
36 months from the date of manufacture.

PRESENTATION :
SELECTOR contains Levonorgestrel 0.750 mg.
1 blister of 2 tablets is packed in a box.

Disclaimer : For the use of a Registered Medical Practitioner or a Hospital or a Institution only. Also it is not intended to be used by healthcare professionals or patients for the purpose of prescribing or administering these products. Questions regarding the complete and current content of product labeling / specification / presentation should be directed to SGPharma.