CYSTORELINE

Indications

• Metabolic disorders
• Energy substrate in clinical nutrition
• Potential use in conditions requiring enhanced energy metabolism

Dosage

Children: Refer to the BNF for Children for appropriate dosing guidelines.

Adults: Refer to specific clinical guidelines as dosages may vary based on the condition being treated. Consultation with a healthcare professional is recommended.

Mechanism of action

Diacetate is metabolized into acetate, which can enter various metabolic pathways. Acetate serves as a substrate for the synthesis of acetyl-CoA, a key molecule in energy metabolism and fatty acid synthesis. The conversion of acetate into acetyl-CoA is facilitated by the enzyme acetyl-CoA synthetase, linking it to the citric acid cycle and enabling ATP production.

Pharmacodynamics

Diacetate functions primarily through its conversion to acetate, influencing energy metabolism. Acetate plays a role in the regulation of gluconeogenesis and lipogenesis. The pharmacodynamics of diacetate are linked to its ability to provide energy substrates and regulate metabolic pathways, impacting overall metabolic homeostasis.

Pharmacokinetics

Diacetate is absorbed and metabolized in the liver, where it is converted to acetate. The systemic circulation allows acetate to be distributed throughout the body. The elimination of acetate is primarily through urinary excretion, with a half-life that varies based on metabolic demand and individual patient factors. The metabolism of acetate is influenced by dietary intake and metabolic state.

Pregnancy

Safety in pregnancy has not been established. Use with caution and only if the benefits outweigh the risks.

Breast-feeding

Limited data available. Use with caution and only if the benefits outweigh the risks.

Storage

Store in a cool, dry place away from direct sunlight. Keep out of reach of children.

Indications

• Assessment of anterior pituitary function
• Treatment of delayed puberty
• Induction of ovulation in hypothalamic amenorrhea
• Management of infertility caused by hypogonadotropic hypogonadism

Dosage

Adults: By intramuscular injection, initially 1 mg daily, alternatively 1 mg every 12 hours in acute cases. This can be reduced to 1 mg every 2–3 days, followed by 1 mg once weekly, or alternatively 500 micrograms every 2–3 days.

Mechanism of action

Gonadorelin stimulates the synthesis and release of LH and FSH from the anterior pituitary gland, mimicking the physiological release of GnRH from the hypothalamus. It is essential for controlling reproductive functions such as follicular growth, ovulation, and maintenance of the corpus luteum in females, as well as spermatogenesis in males. The pulsatile secretion of GnRH is necessary for effective pituitary response and reproductive function.

Pharmacodynamics

Gonadorelin is responsible for the release of LH and FSH from the anterior pituitary. Its action is influenced by the frequency and amplitude of GnRH pulses, alongside feedback from androgens and estrogens. A consistent pulsatile release is crucial for normal reproductive functionality, including ovulation in females and sperm production in males. Its pharmacological effects are significant in conditions related to reproductive health.

Pharmacokinetics

Gonadorelin has a short half-life, necessitating continuous infusion via infusion pumps for effective clinical use. The pharmacokinetic profile supports its application in conditions requiring controlled stimulation of gonadotropin release. The drug's bioavailability and tissue distribution allow it to exert localized effects on the anterior pituitary, leading to the release of key reproductive hormones.

Contra-indications

• Acute psychosis
• Adrenogenital syndrome
• Active infectious diseases
• History of hypersensitivity to tetracosactide/corticotrophins or excipients
• Severe hypertension
• Diabetes mellitus (without dosage adjustment)
• Recent intestinal anastomosis
• Psychological disturbances

Adverse effects

• Anaphylaxis
• Hypertension
• Increased risk of infection
• Leukocytosis
• Malaise
• Menstrual irregularities
• Muscle weakness
• Nausea
• Osteonecrosis
• Osteoporosis
• Pancreatitis
• Papilloedema
• Psychiatric disorders
• Seizures
• Skin reactions
• Tendon rupture
• Thromboembolism
• Vasculitis
• Weight increase
• Vomiting
• Vertigo

Interactions

• Antihypertensives (may require dosage adjustment)
• Diabetes medications (may require dosage adjustment)

Precautions

• Patients with a history of allergies, especially asthma
• Monitor patients for signs of psychological disturbances
• Use with caution in patients with a history of thromboembolism
• Systemic effects may occur due to the potent nature of hormone therapy

Pregnancy

Avoid use unless essential for diagnostic purposes.

Breast-feeding

Avoid use unless essential for diagnostic purposes.

Storage

Store in a cool, dry place, away from light. Follow specific manufacturer's guidelines for storage conditions.

Formulations

• 250 micrograms/1 ml solution for injection in ampoules

Mechanism of action

Systemic - Like naturally occurring gonadotropin-releasing hormone (GnRH), gonadorelin primarily stimulates the synthesis and release of luteinizing hormone (LH) from the anterior pituitary gland. Follicle-stimulating hormone (FSH) production and release is also increased by gonadorelin, but to a lesser degree. In prepubertal females and some gonadal function disorders, the FSH response may be greater than the LH response. For the treatment of amenorrhea, delayed puberty, and infertility the administration of gonadorelin is used to simulate the physiologic release of GnRH from the hypothalamus in treatment of delayed puberty, treatment of infertility caused by hypogonadotropic hypogonadism, and induction of ovulation in those women with hypothalamic amenorrhea. This results in increased levels of pituitary gonadotropins LH and FSH, which subsequently stimulate the gonads to produce reproductive steroids.

Pharmacodynamics

Gonadorelin is responsible for the release of follicle stimulating hormone and leutinizing hormone from the anterior pitutitary. In the pituitary GnRH stimulates synthesis and release of FSH and LH, a process that is controlled by the frequency and amplitude of GnRH pulses, as well as the feedback of androgens and estrogens. The pulsatility of GnRH secretion has been seen in all vertebrates, and it is necessary to ensure a correct reproductive function. Thus a single hormone, GnRH, controls a complex process of follicular growth, ovulation, and corpus luteum maintenance in the female, and spermatogenesis in the male. Its short half life requires infusion pumps for its clinical use