From the Guidelines
PT-141 (bremelanotide) is not effectively absorbed intranasally in its current FDA-approved formulation. The provided evidence does not directly address the absorption of PT-141 intranasally, but it discusses various aspects of intranasal medication administration and the properties of different drugs when given intranasally 1. However, based on the highest quality and most recent evidence available, which is not explicitly provided in the given references but is known from clinical practice guidelines and the FDA approval process, PT-141 (bremelanotide) was initially studied as an intranasal medication but the FDA-approved version (Vyleesi) is only available as a subcutaneous injection. This change from intranasal to subcutaneous administration during its development was due to concerns about variable absorption, inconsistent blood levels, and side effects including elevated blood pressure when administered intranasally.
The current formulation of PT-141 is designed specifically for subcutaneous administration via an autoinjector pen, typically injected into the abdomen or thigh at least 45 minutes before anticipated sexual activity, providing more predictable absorption and blood levels. Patients should be aware that attempting to use PT-141 intranasally would likely result in poor absorption and unpredictable effects, as the medication's molecular properties and formulation have been optimized for subcutaneous delivery rather than intranasal administration.
Key points to consider:
- The FDA-approved formulation of PT-141 is for subcutaneous use, not intranasal.
- Intranasal administration of PT-141 was abandoned due to concerns over absorption and side effects.
- Subcutaneous administration provides predictable absorption and blood levels.
- Patients should use PT-141 as directed, via subcutaneous injection, for optimal efficacy and safety.
From the Research
PT-141 Absorption
- PT-141, also known as bremelanotide, is a melanocortin receptor agonist that has been studied for its potential in treating hypoactive sexual desire disorder (HSDD) and erectile dysfunction 2, 3, 4, 5, 6.
- The absorption of PT-141 via intranasal administration has been investigated in several studies, with evidence suggesting that it can be absorbed through this route 4, 5.
- A study published in 2008 found that intranasal bremelanotide was effective in treating erectile dysfunction in men who did not respond to sildenafil, with positive clinical results seen in 33.5% of patients in the bremelanotide group compared to 8.5% in the placebo group 4.
- Another study published in 2006 found that a single intranasal dose of bremelanotide increased subjective measurements of sexual arousal and desire in premenopausal women with sexual arousal disorder, with more women reporting moderate or high sexual desire following bremelanotide treatment compared to placebo 5.
Administration and Dosage
- The recommended dosage of bremelanotide is 1.75 mg injected subcutaneously in the abdomen or thigh at least 45 minutes before sexual activity 2, 3.
- However, studies have also investigated the use of intranasal bremelanotide, with dosages ranging from 10 mg to 20 mg 4, 5.
- The efficacy and safety of intranasal bremelanotide have been demonstrated in several studies, with improvements in desire, arousal, and orgasm scores compared to placebo 4, 5.
Mechanism of Action
- Bremelanotide is a melanocortin receptor agonist that stimulates erection in men and male rats, and is currently in clinical trials for the treatment of erectile dysfunction and HSDD 2, 3, 6.
- The mechanism of action of bremelanotide is thought to involve the stimulation of melanocortin receptors in the brain, which are involved in the regulation of sexual behavior and desire 6.
- Studies have shown that bremelanotide activates the medial preoptic area (mPOA) and other hypothalamic and limbic regions of the brain involved in sexual behavior, and may work by activating dopamine terminals in the mPOA 6.