Synarel

Synarel Uses, Dosage, Side Effects, Food Interaction and all others data.

Synarel is a potent synthetic agonist of gonadotropin-releasing hormone with 3-(2-naphthyl)-D-alanine substitution at residue 6. Synarel has been used in the treatments of central precocious puberty and endometriosis.

Synarel is a potent agonistic analog of gonadotropin-releasing hormone (GnRH). At the onset of administration, nafarelin stimulates the release of the pituitary gonadotropins, luteinizing hormone (LH) and follicle-stimulating hormone (FSH), resulting in a temporary increase of gonadal steroidogenesis. Repeated dosing abolishes the stimulatory effect on the pituitary gland. Twice daily administration leads to decreased secretion of gonadal steroids by about 4 weeks; consequently, tissues and functions that depend on gonadal steroids for their maintenance become quiescent. After nafarelin therapy is discontinued, pituitary and ovarian function normalize and estradiol serum concentrations increase to pretreatment levels. Recurrences of endometriosis are frequent after cessation of any hormonal therapy, or surgery that leaves the ovaries and/or uterus intact.

Synarel
Uses
Dosage
Side Effect
Precautions
Interactions
Uses during Pregnancy
Uses during Breastfeeding
Accute Overdose
Food Interaction
Half Life
Volume of Distribution
Clearance
Interaction With other Medicine
Contradiction
Storage

Trade Name	Synarel
Availability	Prescription only
Generic	Nafarelin
Nafarelin Other Names	Nafarelin, Nafarelina, Nafaréline, Nafarelinum
Related Drugs	Supprelin LA, tamoxifen, Lupron, norethindrone, medroxyprogesterone, Provera, leuprolide, Sprintec, Orilissa, triptorelin
Weight	0.2mg/inh,
Type	Nasal spray
Formula	C₆₆H₈₃N₁₇O₁₃
Weight	Average: 1322.496 Monoisotopic: 1321.635625801
Protein binding	Approximately 80%.
Groups	Approved
Therapeutic Class
Manufacturer	Pfizer, SA
Available Country	Australia, Canada, United States, Spain,
Last Updated:	September 19, 2023 at 7:00 am

Uses

Synarel is a gonadotropin releasing hormone agonist used to treat central precocious puberty.

For treatment of central precocious puberty (true precocious puberty, GnRH-dependent precocious precocity, complete isosexual precocity) in children of both sexes and for the treatment of endometriosis.

Synarel is also used to associated treatment for these conditions: Central Precocious Puberty (CPP), Endometriosis

How Synarel works

Like GnRH, initial or intermittent administration of nafarelin stimulates release of the gonadotropins luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the pituitary gland, which in turn transiently increases production of estradiol in females and testosterone in both sexes. However, with continuous daily administration, nafarelin continuously occupies the GnRH receptor, leading to a reversible down-regulation of the GnRH receptors in the pituitary gland and desensitization of the pituitary gonadotropes. This causes a significant and sustained decline in the production of LH and FSH. A decline in gonadotropin production and release causes a dramatic reversible decrease in synthesis of estradiol, progesterone, and testosterone by the ovaries or testes. Like normal endometrium, endometriotic implants contain estrogen receptors. Estrogen stimulates the growth of endometrium. Use of nafarelin induces anovulation and amenorrhea and decreases serum concentrations of estradiol to the postmenopausal range, which induces atrophy of endometriotic implants. However, nafarelin does not abolish the underlying pathophysiology of endometriosis. In children with central precocious puberty receiving nafarelin, serum LH, testosterone, and estradiol concentrations return to prepubertal levels. This results in the supression of secondary sexual characteristics and decrased rate of linear growth and skeletal maturation. Following disconinuation of nafarelin, the effects of the drug is reversed, meaning FSH and LH concentrations usually return to pretreatment levels.

Toxicity

In experimental animals, a single subcutaneous administration of up to 60 times the recommended human dose (on a µg/kg basis, not adjusted for bioavailability) had no adverse effects. At present, there is no clinical evidence of adverse effects following overdosage of GnRH analogs.

Food Interaction

Avoid excessive or chronic alcohol consumption. Ingesting alcohol in excess may increase the risk of bone thinning associated with taking nafarelin.

Synarel Disease Interaction

Major: abnormal vaginal bleedingModerate: seizures, bone density loss, ovarian cysts

Elimination Route

Rapidly absorbed into the systemic circulation after intranasal administration. Bioavailability from a 400 µg dose averaged 2.8% (range 1.2 to 5.6%). Not absorbed after oral administration.