Vyleesi Self-Injection Technique: Step-by-Step Guide for Bremelanotide

What Is Bremelanotide and How Was It Approved?

Bremelanotide is a synthetic cyclic heptapeptide melanocortin receptor agonist approved by the FDA in June 2019 under the brand name Vyleesi for the treatment of hypoactive sexual desire disorder (HSDD) in premenopausal women. HSDD is defined as persistent or recurrent low sexual desire accompanied by marked distress, without a clear relationship to a co-existing medical condition, interpersonal difficulty, or another drug effect. [1]

The FDA based its approval on the two phase 3 RECONNECT trials published in Obstetrics and Gynecology (2019). Pooled across both studies (N=1,267), bremelanotide produced a statistically significant increase in the desire domain of the Female Sexual Function Index (FSFI-D) and a statistically significant decrease in the Female Sexual Distress Scale-Desire/Arousal/Orgasm (FSDS-DAO) item 13 score compared with placebo (P<0.001 for both co-primary endpoints). [1]

Regulatory History and Manufacturer

Palatin Technologies developed bremelanotide after observing unexpected arousal effects in a melanocortin-based tanning peptide (PT-141) during early clinical work. HSDD affects an estimated 8.9% of U.S. Premenopausal women at any one time, making a centrally acting, non-hormonal option clinically meaningful. [2] AMAG Pharmaceuticals (later reacquired by Palatin and licensed to Cosette Pharmaceuticals) holds the commercial marketing rights in the United States.

Why Central Activation Matters

Unlike topical or hormonal therapies, bremelanotide acts directly in the brain's melanocortin system. This mechanism is distinct from flibanserin (Addyi), which works on serotonin and dopamine receptors. That distinction matters clinically because the two drugs carry different contraindication profiles, different administration timing requirements, and different side-effect burdens.

How Does Vyleesi Work? Mechanism of Action

Bremelanotide is a non-selective agonist at melanocortin receptors 1, 3, 4, and 5 (MC1R, MC3R, MC4R, MC5R), with MC4R activation in the hypothalamus considered the primary driver of its pro-sexual effect. Melanocortin receptor signaling in the paraventricular nucleus of the hypothalamus modulates dopaminergic tone in mesolimbic circuits that encode motivational salience, including sexual motivation. [3]

Melanocortin 4 Receptor Pathway

MC4R is a G-protein-coupled receptor. Agonist binding activates adenylyl cyclase via Gs, raises intracellular cyclic AMP, and downstream increases dopamine release in the medial preoptic area. Animal studies using selective MC4R agonists and MC4R-knockout mice confirm this receptor is necessary and sufficient for the pro-erectile and pro-sexual effects observed in rodents. The MC4R pathway is also partially responsible for bremelanotide's transient blood-pressure effects, discussed in the safety section below. [4]

Pharmacokinetics

After a 1.75 mg subcutaneous dose, bremelanotide reaches peak plasma concentration (Cmax) in approximately 1 hour. The mean absolute bioavailability of subcutaneous bremelanotide is approximately 100% because the route bypasses hepatic first-pass metabolism entirely. [5] Half-life is 2.7 hours. The drug is metabolized via hydrolysis of peptide bonds; renal excretion accounts for roughly 64% of recovery. Dose adjustment is not required for mild-to-moderate renal impairment (eGFR ≥30 mL/min/1.73 m²), but the drug is not recommended if eGFR <30 mL/min/1.73 m².

Onset and Duration of Effect

The 45-minute pre-activity window specified in labeling corresponds to the pharmacokinetic profile. Plasma concentrations are rising rapidly at 45 minutes post-injection and are near Cmax by 60 minutes. FDA review documents note that earlier administration at 30 minutes was associated with slightly higher nausea rates, supporting the 45-minute recommendation. [5]

Vyleesi Autoinjector: Device Overview

The Vyleesi autoinjector is a single-dose, prefilled, disposable pen containing 1.75 mg bremelanotide in 0.3 mL aqueous solution. The pen uses a hidden needle design. The needle extends automatically on activation and retracts after the dose is delivered. This design reduces needle-anxiety and injection-site error.

Device Components

• Cap: Remove just before injection; do not recap.
• Activation button: Thumb-activated, located on the top of the pen.
• Viewing window: Confirms solution clarity; the solution should be clear to slightly yellow. Do not use if cloudy, discolored, or containing visible particles.
• Needle guard: Automatically locks after injection, rendering the pen safe for single-handed disposal.

Storage Requirements

Store at controlled room temperature, 20°C to 25°C (68°F to 77°F), with excursions permitted from 15°C to 30°C. Keep away from direct sunlight. The FDA prescribing information specifies that Vyleesi should not be frozen; freezing denatures the peptide. [5] Pens must not be refrigerated for long-term storage, though brief cold exposure during shipping is generally acceptable per manufacturer guidance.

Step-by-Step Vyleesi Self-Injection Technique

Correct injection technique reduces bruising, improves dose delivery, and minimizes injection-site reactions. The steps below synthesize the FDA-approved prescribing information with practical clinical refinements used in ambulatory sexual medicine practice.

Step 1: Gather Supplies and Wash Hands

Collect the autoinjector pen, one alcohol swab, and a sharps container. Wash hands with soap and water for at least 20 seconds. Proper hand hygiene before any subcutaneous injection reduces the risk of injection-site infection, though injection-site infection with bremelanotide has not been reported in clinical trials at measurable frequency. [6]

Step 2: Choose and Prepare the Injection Site

Two sites are approved:

1. Abdomen: At least 2 inches (5 cm) away from the navel. Avoid the beltline, waistband area, or any zone with active bruising, scarring, or tattoo ink.
2. Outer thigh: Middle third of the outer thigh. Avoid the inner thigh and knee area.

Rotate sites with each dose to prevent lipohypertrophy. Clean the selected area with an alcohol swab using a circular outward motion, then allow the skin to air-dry for 10 to 15 seconds. Injecting through wet skin increases stinging.

Step 3: Remove the Cap and Inspect the Solution

Pull the cap straight off, do not twist. Check the viewing window. The solution must be clear or pale yellow with no particles. If anything appears abnormal, discard the pen and use a replacement.

Step 4: Position the Pen and Inject

Hold the pen at a 90-degree angle to the skin surface. Do not pinch the skin; the needle length is designed for flat, unpinched subcutaneous tissue. Press the pen firmly against the skin until the base is flush with the skin surface, then press the activation button with your thumb. Hold the pen in place for 5 seconds after pressing the button to ensure complete dose delivery. You will hear or feel a click at activation and a second click when the needle retracts.

Step 5: Remove and Dispose

Lift the pen straight off the skin. The needle guard will have locked automatically. Dispose of the pen in an approved sharps container immediately. Do not re-cap, recap, or attempt to disassemble the pen. Apply gentle pressure to the injection site with a clean cotton ball for 10 to 15 seconds if any bleeding occurs; do not rub.

Step 6: Set a Timer

Note the time of injection so you know when the 45-minute window before sexual activity begins. Effects may be present for up to 12 hours, though peak central effect correlates with peak plasma concentration at roughly 60 minutes.

Clinical Evidence: The RECONNECT Trials

The two key RECONNECT trials (BMT-301 and BMT-302) were randomized, double-blind, placebo-controlled, event-driven crossover studies in premenopausal women with DSM-5-diagnosed HSDD. The pooled population of N=1,267 women had a mean age of 38 years and a mean HSDD duration of 5.5 years. [1]

Co-Primary Endpoints

The FDA required two co-primary endpoints: change from baseline in FSFI-desire domain score and change from baseline in FSDS-DAO item 13 (distress about low sexual desire). Bremelanotide met both endpoints in each trial individually and in the pooled analysis (P<0.001). [1]

Magnitude of Benefit

In the pooled RECONNECT analysis, the mean change in FSFI-desire score was +0.35 for bremelanotide versus +0.22 for placebo (a statistically significant but modest absolute difference). The FSDS-DAO item 13 score decreased by 0.27 points more with bremelanotide than with placebo. [1] Critics have noted the absolute effect size is small; the FDA acknowledged this in its review but concluded the drug met its pre-specified endpoints and represented an unmet need in a population with no centrally acting alternatives available at approval time (flibanserin had been approved in 2015 but requires daily dosing).

Responder Rates

Roughly 25% of bremelanotide-treated women reported a meaningful improvement in desire ("much improved" or "very much improved" on the Patient Global Impression of Change) versus 17% of placebo-treated women. These responder data are worth considering when counseling patients about realistic expectations.

Managing Side Effects

Nausea

Nausea is the most frequently reported adverse effect, occurring in approximately 40% of subjects in RECONNECT versus 1% of placebo subjects. Pre-treatment with oral ondansetron 8 mg taken 30 minutes before bremelanotide reduced nausea incidence in a post-hoc subgroup analysis, though this approach is not formally listed in labeling. [1] For patients who remain intolerant despite antiemetic pretreatment, dose timing adjustment (administering closer to 60 minutes before activity rather than 45) may slightly reduce peak-concentration nausea while maintaining efficacy.

Flushing and Hot Flashes

Flushing occurred in approximately 20% of bremelanotide-treated women versus 2% of placebo. This reflects MC1R agonism in skin vasculature and is dose-related. Flushing is typically mild and transient (less than 60 minutes).

Transient Blood Pressure Increase

A mean increase in systolic blood pressure of approximately 2 mmHg and diastolic of 1 mmHg was observed in RECONNECT. The FDA label carries a cardiovascular warning and contraindications in women with known cardiovascular disease including uncontrolled hypertension (baseline blood pressure above 130/80 mmHg). [5] Blood pressure typically returns to baseline within 12 hours. Clinicians should obtain a baseline blood pressure before prescribing.

Hyperpigmentation

Focal hyperpigmentation of the face, gums, or breasts was reported in approximately 1% of women using bremelanotide over 52 weeks in long-term safety studies. This reflects MC1R activation in melanocytes. The American Academy of Dermatology guidelines on acquired hyperpigmentation recommend sun protection as standard mitigation, though bremelanotide-associated hyperpigmentation cases have not been formally evaluated in dermatology RCTs. [7] Patients with a personal or family history of melasma should be counseled about this risk before starting therapy.

Contraindications and Drug Interactions

Absolute Contraindications

Per FDA prescribing information, bremelanotide is contraindicated in: [5]

• Women with known cardiovascular disease (coronary artery disease, history of stroke, uncontrolled hypertension)
• Concurrent use of naltrexone (mutual pharmacodynamic antagonism)

Drug Interactions

Bremelanotide slows gastric emptying and can reduce the rate and extent of absorption of orally co-administered drugs. This interaction is clinically relevant for drugs with narrow therapeutic indices and time-sensitive absorption profiles, such as certain antibiotics or oral contraceptive pills taken on the same evening. [1] Prescribers should counsel women using oral contraceptives to take their pill at least 1 hour before or 2 hours after bremelanotide.

Use in Perimenopausal Women

The FDA approved bremelanotide specifically for premenopausal women. Limited data exist for perimenopausal or postmenopausal women. The Endocrine Society's 2019 clinical practice guideline on female sexual dysfunction notes that systemic estrogen deficiency in postmenopausal women independently suppresses desire, and this should be addressed before or alongside any centrally acting agent. [8]

Who Is a Good Candidate for Vyleesi?

The ideal bremelanotide candidate is a premenopausal woman who:

• Has a confirmed DSM-5 HSDD diagnosis (low desire causing personal distress, not adequately explained by relationship factors or another medical condition)
• Has normal blood pressure at baseline (below 130/80 mmHg)
• Prefers an as-needed approach rather than daily pharmacotherapy
• Has tried or considered psychosexual therapy and wants a pharmacological adjunct
• Tolerates subcutaneous injections (prior insulin use, fertility injections, or comfort with autoinjectors is reassuring)

Women with a strong aversion to injections may find the as-needed oral option flibanserin (Addyi, 100 mg nightly) more acceptable, despite its daily-dosing burden and the 2-hour alcohol restriction. Comparative head-to-head data between bremelanotide and flibanserin do not yet exist in the published literature. [1]

Practical Prescribing Considerations

Packaging and Cost

Vyleesi is dispensed in a box containing four single-dose autoinjector pens. Given the as-needed design (tied to sexual activity rather than a daily schedule), a single box may last weeks to months depending on frequency of use. Wholesale acquisition cost exceeds $900 per box as of 2024; prior authorization is required by most commercial payers, and HSDD must be documented in the medical record.

Initiation Counseling Checklist

Before the first injection, clinicians should confirm:

1. Baseline blood pressure below 130/80 mmHg
2. Review of the gastric emptying interaction with any concurrent narrow-therapeutic-index oral medications
3. Informed consent including the risk of hyperpigmentation with prolonged use
4. Instruction on pre-dose ondansetron 8 mg oral for nausea prevention
5. Demonstration of autoinjector technique using the device trainer provided by the manufacturer or the instructional video available through the Vyleesi patient support program

Discontinuation Criteria

Discontinue bremelanotide if the patient develops new-onset hypertension above 140/90 mmHg, experiences significant hyperpigmentation, or develops any cardiovascular symptom (chest pain, shortness of breath, or palpitations) within 12 hours of a dose. The FDA label specifies that bremelanotide should not be used in women with cardiovascular disease. [5]

Bremelanotide Versus Other HSDD Treatments

| Treatment | Mechanism | Dosing | Key Side Effect | Contraindication | |---|---|---|---|---| | Bremelanotide (Vyleesi) | MC4R agonist | As needed SC | Nausea (40%) | CVD, hypertension | | Flibanserin (Addyi) | 5-HT1A agonist / 5-HT2A antagonist | 100 mg nightly PO | Somnolence, hypotension | Alcohol, CYP3A4 inhibitors | | Testosterone (off-label) | Androgen receptor agonist | Daily transdermal | Acne, hirsutism | Androgen-sensitive cancer | | Psychosexual therapy | Cognitive-behavioral | Weekly sessions | None pharmacologic | None |

The International Society for the Study of Women's Sexual Health (ISSWSH) 2019 consensus recommendation places both bremelanotide and flibanserin as first-line pharmacological options for HSDD, with the choice driven by patient preference and tolerability profile. [9]