Fibristal

Uses

Fibristal Acetate is used before surgery to treat moderate to severe symptoms of uterine fibroids, which are noncancerous (benign) tumors of the womb (uterus). Fibristal Acetate is used in adult women who have not yet reached menopause.

Fibristal is also used to associated treatment for these conditions: Moderate Uterine Fibroids, Severe Uterine Fibroids, Emergency Contraception

How Fibristal works

The exact mechanism of action of ulipristal has been heavily debated . On one hand, the majority of official prescribing information labels, monographs, and prior research studies for ulipristal indicated as an emergency contraceptive suggest that its primary mechanism of action revolves around inhibiting or delaying ovulation by suppressing surges in LH that result in the postponement of follicular rupture .

Conversely, some of the latest investigations pertaining to ulipristal's mechanism of action as an emergency contraceptive propose that it principally elicits its action by preventing embryo implantation, as opposed to preventing ovulation . Although previous investigations have shown that ulipristal essentially has the ability to prevent ovulation equivalent to placebo (ie. null effect or ability) when administered during LH peaks one to two days before ovulation, the agent still demonstrates a stable and consistently high contraceptive effect of approximately >=80% when used at this time . Subsequently, current studies attempt to investigate how ulipristal could elicit emergency contraception via ovulation prevention under circumstances where ovulation had already clearly been observed . Endometrial biopsy samples studied from such circumstances in such investigations subsequently show that the administered ulipristal causes endometrial tissue to become inhospitable and unsuitable for embryo implantation where a variety of genes characteristic of receptive, pro-gestational endometrium are downregulated .

Nevertheless, most if not all proposed mechanisms commonly agree that ulipristal ultimately demonstrates its pharmacological effects by binding to human progesterone receptors and prevents natural, endogenous progesterone from occupying such receptors . Regardless, however, considering current and on-going research into ulipristal's ability to prevent embryo implantation, the notion that the medication can elicit post-fertilization effects potentially raises alerts and/or ethical debates over the use of ulipristal owing to potential abortifacient activity , which is considered to be on par or equipotent to that of mifepristone . Attention should be drawn to the fact that some prescribing information, however, such as the US FDA label for ulipristal indicated for emergency contraception, has included new supplementary commentary since 2018 that directly warns about ulipristal not being indicated for termination of existing pregnancies and suggesting that ulipristal use may confer alterations to the endometrium that may affect implantation and contribute to efficacy .

In the treatment of fibroids, ulipristal has been shown to exert direct actions on fibroids reducing their size through inhibition of cell proliferation and induction of apoptosis.

Dosage

Fibristal dosage

Fibristal acetate is taken by mouth and the recommended dose is one tablet (5 mg) a day for up to three months. The three month treatment can be repeated but only once. Treatment should always be started during the first week of the menstrual cycle (period bleeding).

Side Effects

Common side effects are Endometrial thickening, Hot flush, Headache, Uterine haemorrhage

Precaution

Fibristal acetate should only be prescribed after careful diagnosis. Pregnancy should be precluded prior to treatment.

• Contraception
• Renal impairment
• Hepatic impairment
• Asthma patients
• Endometrial changes

Patients should be informed that treatment with ulipristal acetate usually leads to a significant reduction in menstrual blood loss or amenorrhea within the first 10 days of treatment. If the excessive bleeding persist, patients should notify their physician. Menstrual periods will generally return within 4 weeks after the end of the treatment course

Food Interaction

• Take with or without food. High-fat food increases drug absorption, but not to a clinically significant extent.

Fibristal Drug Interaction

Minor: diltiazem, diltiazemUnknown: aspirin, charcoal, lorazepam, amoxicillin / clavulanate, nebivolol, sulfamethoxazole / trimethoprim, ubiquinone, copper gluconate, glucose, estradiol, ethanol, fluticasone, glycerin, acetaminophen, bioflavonoids, tramadol, cyanocobalamin, cholecalciferol

Fibristal Disease Interaction

Moderate: hepatic impairment, renal impairment

Elimination Route

Tmax, healthy subjects, single oral dose = 60-90 minutes; Cmax, healthy subjects, single oral dose = 176 ± 89 ng/mL; AUC(0-∞), healthy subjects, single oral dose = 556 ± 260 ng·h/mL;

Half Life

Mean elimination half-life, single oral dose, healthy subject = 32.4 ± 6.3 hours

Clearance

Mean oral clearance, single oral dose, healthy subject (CL/F) = 76.8 ± 64.0L/h

Pregnancy & Breastfeeding use

Pregnancy Category X. Fibristal acetate is contraindicated during pregnancy. Fibristal acetate is excreted in human milk and is not recommended.

Contraindication

• Hypersensitivity to the active substance or to any of the excipients.
• Pregnancy and breastfeeding.
• Genital bleeding of unknown aetiology or for reasons other than uterine fibroids.
• Uterine, cervical, ovarian or breast cancer.

Acute Overdose

Experience with ulipristal acetate overdose is limited. Single doses up to 200 mg and daily doses of 50 mg for 10 consecutive days were administered to a limited number of subjects, and no severe or serious adverse reactions were reported.

Storage Condition

Keep protected from light & moisture, store below 25° C. Keep out of reach of children.

Innovators Monograph

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