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  5. Gonadotropin releasing hormone analogues: Nasal spray or injections?
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  5. Gonadotropin releasing hormone analogues: Nasal spray or injections?

Gonadotropin releasing hormone analogues: Nasal spray or injections?

Gonadotropin releasing hormone analogues are medications that are used as puberty blockers in trans adolescents and as antiandrogens in trans women.

Usually in physiological puberty, the hypothalamus produces gonadotropin releasing hormone, which binds to receptors in the pituitary gland. This stimulates the secretion of follicular stimulating hormone and luteinising hormone by the pituitary gland. Follicular stimulating hormone and luteinising hormone then stimulate the secretion of oestrogen or testosterone from the ovaries or testes.

Gonadotropin releasing hormone analogues work by binding to the gonadotropin releasing hormone receptors. This blocks the production of follicular stimulating hormone and luteinising hormone by the pituitary gland. In turn, this suppresses the production of oestrogen or testosterone from the ovaries or testes.

Gonadotropin releasing hormone analogues come in different forms. Leuprorelin and triptorelin come as injections. Nafarelin comes as a nasal spray.

Injections

Leuprorelin (Prostap®)

This is administered as an injection every 4 to 12 weeks. The usual dose is 11.25mg every 12 weeks, but different people may require different dose frequencies depending on their specific needs.

Leuprorelin can be administered as either an intramuscular injection (into the muscle) or as a subcutaneous injection (under the skin). The intramuscular injection can only be administered by a trained healthcare professional. However, the subcutaneous injection can be self-administered if you have had the required injection training.

The preparation is available as a powder along with separate reconstituting fluid in a composite syringe. After it is injected, the medication will solidify beneath the injection site and will slowly be released into the body over several weeks. It is important to inject the preparation immediately after reconstitution to avoid solidification of the medication before injection (De Sanctis et al., 2019).

Leuprorelin has been established as safe and well-tolerated, with very few side effects.

Triptorelin (Decapeptyl®)

This is administered as an intramuscular injection every 10 to 14 weeks. The usual dose is 11.25mg every 12 weeks, but different people may require different dose frequencies depending on their specific needs.

Triptorelin is administered an intramuscular injection (into the muscle). This can only be administered by a trained person. Therefore, self-administration is generally not recommended with triptorelin.

The preparation is available as a powder along with separate reconstituting fluid in a composite syringe. After it is injected, the medication will solidify beneath the injection site and will slowly be released into the body over several weeks. It is important to inject the preparation immediately after reconstitution to avoid solidification of the medication before injection (De Sanctis et al., 2019).

Triptorelin has been established as safe and well-tolerated, with very few side effects.

Nasal spray

Nafarelin (Synarel®)

This is administered as a nasal spray that is taken twice a day. Each spray contains 200mcg nafarelin, and so the total daily dose is 400mcg.

The pump should produce a fine mist, which can only happen by a quick and firm pumping action. It is fine to see some larger droplets of liquid within the fine mist. However, if the medication comes out of the pump as a thin stream of liquid instead of a fine mist, it may not work as well, and so it is recommended that you talk to your pharmacist. It is important to clean the spray tip before and after every use. Failure to do this may result in a clogged tip that may cause you not to get the right amount of medicine that is prescribed for you.

Nafarelin has been established as safe and well-tolerated, with very few side effects.

Comparison

Gonadotropin releasing hormone analogue nasal spray and injections are equally effective at suppressing oestrogen and testosterone when used properly.

While there has been very little research comparing the different routes of administration in the trans population, a study comparing the different routes of buserelin (a gonadotropin releasing hormone analogue) in cis men with prostate cancer found that the nasal spray and the subcutaneous injection were equally effective at suppressing testosterone (Rajfer et al., 1986). Clinical experience has also suggested that leuprorelin, triptorelin, and nafarelin are comparably effective at suppressing oestrogen and testosterone as part of gender affirming medical treatment.

Therefore, the choice of whether to choose injections or the nasal spray will depend on other considerations, including the availability of injection training, how comfortable you are with needles, how frequently you want to take the medication, and so on.

References

De Sanctis, V., Soliman, A. T., Di Maio, S., Soliman, N., and Elsedfy, H. (2019). “Long-term effects and significant Adverse Drug Reactions (ADRs) associated with the use of Gonadotropin-Releasing Hormone analogs (GnRHa) for central precocious puberty: a brief review of literature”. Acta bio-medica : Atenei Parmensis90 (3): 345–359. 

Rajfer, J., Handelsman, D. J., Crum, A., Steiner, B., Peterson, M., and Swerdloff, R. S. (1986). “Comparison of the efficacy of subcutaneous and nasal spray buserelin treatment in suppression of testicular steroidogenesis in men with prostate cancer”. Fertility and Sterility. 46(1): 104-110. 

Updated on April 10, 2024

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