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P A R T 7  Drugs acting on the reproductive system

TABLE 40.2

DRUGS IN FOCUS Fertility drugs

Drug name

Dosage/route

Usual indications

cetrorelix (Cetrotide)

3 mg SC during early follicular phase or 0.25 mg SC on day five or six of stimulation and then every day until human chorionic gonadotropin (HCG) is administered 250 mcg SC, timing depending on indication 500–10,000 International Units SC depending on timing and indication 50–100 mg/day PO, with length of therapy and timing dependent on the particular situation 75–150 International Units/day SC, dose increases based on response; do not exceed 300 International Units/day 75–225 International Units/day SC, dose increases based on response; do not exceed 300 International Units/day 250 mcg/day SC during early follicular phase

Inhibition of premature luteinising hormone (LH) surges in women undergoing controlled ovarian stimulation Induction of final follicular maturation and ovulation induction in infertile women Stimulation of ovulation, hypogonadism, prepubertal cryptorchidism Treatment of infertility; also found to be effective in the treatment of male infertility Stimulation of follicular development in the treatment of infertility and for harvesting of ova for in vitro fertilisation Stimulation of follicular development in the treatment of infertility and for harvesting of ova for in vitro fertilisation Inhibition of premature LH surges in women undergoing controlled ovarian hyperstimulation as part of a fertility program Used in combination with follitropin alfa to stimulate follicle development and help to prepare the uterus for implantation Treatment of anovulatory fertility and controlled ovarian hyperstimulation to induce multiple follicle development

choriogonadotropin alfa (Ovidrel) chorionic gonadotrophin (Pregnyl)

clomiphene (Clomid and others)

follitropin alfa (Gonal-F)

follitropin beta (Follistim)

ganirelix (Orgalutran)

lutropin alfa (Luveris)

75 units SC with follitropin alfa

menopausal

75–150 International Units/day SC for at least 7 days, dose increased based on response; do not exceed 225 International Units/day

gonadotrophin (Menopur)

to stimulate follicles and ovulation or stimulate the hypothalamus to increase FSH and LH levels, leading to ovarian follicular development and maturation of ova. Given in sequence with human chorionic gonadotropin (HCG) to maintain the follicle and hormone produc- tion, these drugs are used to treat infertility in women with functioning ovaries whose partners are fertile. Fertility drugs also may be used to stimulate multiple follicle development for the harvesting of ova for in vitro fertilisation. Cetrorelix inhibits premature LH surges in women undergoing controlled ovarian stimulation by acting as a GnRH antagonist. Chorionic gonadotropin is used to stimulate ovulation by acting like GnRH and affecting FSH and LH release. Follitropin alfa and follitropin beta are FSH molecules; they are injected to stimulate folli- cular development in the treatment of infertility and for harvesting of ova for in vitro fertilisation. See Table 40.2 for usual indications for each fertility drug. Pharmacokinetics These drugs are well absorbed and are treated like endogenous hormones within the body, undergoing hepatic metabolism and renal excretion. Drugs that are

available in injectable form include cetrorelix, chorionic gonadotrophin, choriogonadotropin alpha, follitropin alfa, follitropin beta, lutropin alfa and ganirelix. Clomi- phene is available as an oral agent. Contraindications and cautions These drugs are contraindicated in the presence of primary ovarian failure ( they only work to stimulate functioning ovaries ); thyroid or adrenal dysfunction because of the effects on the hypothalamic–pituitary axis ; ovarian cysts , which could be stimulated and become larger due to the effects of the drugs ; pregnancy due to the potential for serious fetal effects ; idiopathic uterine bleeding, which could represent an underlying problem that could be exacerbated by the stimulatory effects of these drugs ; and known allergy to any fertility drug to avoid hypersensitivity reactions . Caution should be used in women who are breast- feeding because of the risk of adverse effects on the baby, in those with thromboembolic disease because of the risk of increased thrombus formation , as well as in women with respiratory diseases because of alterations in fluid volume and blood flow that could overtax the respira- tory system.