Noret 28 0.03 mg+0.15 mg+75 mg Tablet

Uses

Noret 28 0.03 mg+0.15 mg+75 mg Tablet is also used to associated treatment for these conditions: Folic acid antagonist overdose, Iron Deficiency (ID), Iron Deficiency Anemia (IDA), Oral ContraceptivesEndometrial Hyperplasia, Endometriosis, Hypermenorrhea, Postmenopausal Osteoporosis, Pregnant State, Moderate Menopausal Vasomotor Symptoms, Severe Vasomotor Symptoms Associated With Menopause, Emergency Contraception

How Noret 28 0.03 mg+0.15 mg+75 mg Tablet works

Iron is necessary for the production of hemoglobin. Iron-deficiency can lead to decreased production of hemoglobin and a microcytic, hypochromic anemia.

Mechanism of action on ovulation

Oral contraceptives containing levonorgestrel suppress gonadotropins, inhibiting ovulation. Specifically, levonorgestrel binds to progesterone and androgen receptors and slows the release of gonadotropin-releasing hormone (GnRH) from the hypothalamus. This process results in the suppression of the normal physiological luteinizing hormone (LH) surge that precedes ovulation. It inhibits the rupture of follicles and viable egg release from the ovaries. Levonorgestrel has been proven to be more effective when administered before ovulation.

Mechanism of action in cervical mucus changes

Similar to other levonorgestrel-containing contraceptives, the intrauterine (IUD) forms of levonorgestrel likely prevent pregnancy by increasing the thickness of cervical mucus, interfering with the movement and survival of sperm, and inducing changes in the endometrium, where a fertilized ovum is usually implanted. Levonorgestrel is reported to alter the consistency of mucus in the cervix, which interferes with sperm migration into the uterus for fertilization. Levonorgestrel is not effective after implantation has occurred. Interestingly, recent evidence has refuted the commonly believed notion that levonorgestrel changes the consistency of cervical mucus when it is taken over a short-term period, as in emergency contraception. Over a long-term period, however, levonorgestrel has been proven to thicken cervical mucus. The exact mechanism of action of levonorgestrel is not completely understood and remains a topic of controversy and ongoing investigation.

Effects on implantation*

The effects of levonorgestrel on endometrial receptivity are unclear, and the relevance of this mechanism to the therapeutic efficacy of levonorgestrel is contentious. Prescribing information for levonorgestrel IUDs state that they exert local morphological changes to the endometrium (e.g. stromal pseudodecidualization, glandular atrophy) that may play a role in their contraceptive activity.

Mechanism of action in hormone therapy

When combined with estrogens for the treatment of menopausal symptoms and prevention of osteoporosis, levonorgestrel serves to lower the carcinogenic risk of unopposed estrogen therapy via the inhibition of endometrial proliferation. Unregulated endometrial proliferation sometimes leads to endometrial cancer after estrogen use.

Dosage

Noret 28 0.03 mg+0.15 mg+75 mg Tablet dosage

One tablet should be taken orally with a glass of water.

Side Effects

Toxicity

Acute iron overdosage can be divided into four stages. In the first stage, which occurs up to six hours after ingestion, the principal symptoms are vomiting and diarrhea. Other symptoms include hypotension, tachycardia and CNS depression ranging from lethargy to coma. The second phase may occur at 6-24 hours after ingestion and is characterized by a temporary remission. In the third phase, gastrointestinal symptoms recur accompanied by shock, metabolic acidosis, coma, hepatic necrosis and jaundice, hypoglycemia, renal failure and pulmonary edema. The fourth phase may occur several weeks after ingestion and is characterized by gastrointestinal obstruction and liver damage. In a young child, 75 milligrams per kilogram is considered extremely dangerous. A dose of 30 milligrams per kilogram can lead to symptoms of toxicity. Estimates of a lethal dosage range from 180 milligrams per kilogram and upwards. A peak serum iron concentration of five micrograms or more per ml is associated with moderate to severe poisoning in many.

The oral LD50 in rats is greater than 5000 mg/kg.

An overdose of this drug, like other contraceptives, may cause nausea and withdrawal bleeding. Provide symptomatic treatment in the case of a levonorgestrel overdose and contact the local poison control center. There is no specific antidote for a levonorgestrel overdose.

Precaution

Interaction

Volume of Distribution

One pharmacokinetic study determined a mean steady-state volume of distribution of 1.5 mg of levonorgestrel to be 162.2 L in those with normal BMI and in the range of 404.7 L to 466.4 L in obese patients with a body mass index of at least 30. Mean volume of distribution in 16 patients receiving 0.75 mg of levonorgestrel in another pharmacokinetic study was 260 L. The Plan B one-step FDA label reports an apparent volume of distribution of 1.8 L/kg.

Elimination Route

The efficiency of absorption depends on the salt form, the amount administered, the dosing regimen and the size of iron stores. Subjects with normal iron stores absorb 10% to 35% of an iron dose. Those who are iron deficient may absorb up to 95% of an iron dose.

Orally administered levonorgestrel is absorbed in the gastrointestinal tract while levonorgestrel administered through an IUD device is absorbed in the endometrium. Levonorgestrel is absorbed immediately in the interstitial fluids when it is inserted as a subdermal implant. After insertion of the subdermal implant, the Cmax of levonorgestrel is attained within 2-3 days.The Cmax following one dose of 0.75 mg of oral levonorgestrel is reached within the hour after administration, according to one reference. In a pharmacokinetic study of 1.5 mg of levonorgestrel in women with a normal BMI and those considered to be obese (BMI>30), mean Cmax was found to be 16.2 ng/mL and 10.5 ng/mL respectively. Tmax was found to be 2 hours for those with normal BMI and 2.5 hours for patients with increased BMI. The bioavailability of levonorgestrel approaches 100%.

Mean AUC has been shown to be higher in patients with a normal BMI, measuring at 360.1 h × ng/mL versus a range of 197.28 to 208.1 h × ng/mL in an obese group of patients. Obesity may contribute to decreased efficacy of levonorgestrel in contraception.

Half Life

The elimination half-life of a 0.75 mg dose of 1.5 mg of levonorgestrel ranges between 20-60 hours post-administration. A pharmacokinetic study of women with a normal BMI and BMI over revealed an elimination half-life of 29.7 h and 41.0-46.4 hours, respectively. Another pharmacokinetic study revealed a mean elimination half-life of 24.4 hours after a 0.75 mg dose of levonorgestrel was administered to 16 patients.

Clearance

Clearance was found to 4.8 L/h in healthy female volunteers with a normal BMI, and 7.70-8.51 L/h in obese patients after a single 1.5 mg dose. After a 0.75 mg dose of levonorgestrel in 16 patients in another pharmacokinetic study, mean clearance was calculated at 7.06 L/h. Following levonorgestrel implant removal, the serum concentration falls below 100 pg/mL within the first 96 hours and further falls below the sensitivity of detection within the range of 5 days to 2 weeks.

Elimination Route

Approximately 45% of an oral levonorgestrel dose and its conjugated or sulfate metabolites are found to be excreted in the urine. Approximately 32% of an orally ingested dose is found excreted in feces, primarily in the form of glucuronide conjugates of levonorgestrel.

Pregnancy & Breastfeeding use

Contraindication

Special Warning

Acute Overdose

Storage Condition

Innovators Monograph

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