Vyleesi (Bremelanotide) in Adults 65 and Older: What Geriatric Patients and Their Clinicians Need to Know

What Is Bremelanotide and Why Does Age Matter?

Bremelanotide is a cyclic heptapeptide melanocortin-4 (MC4R) receptor agonist approved by the FDA in June 2019 under the brand name Vyleesi. It is indicated for acquired, generalized HSDD in premenopausal women. The drug's mechanism, transient blood-pressure elevation, and hepatic metabolism all become more clinically significant as patients age. Geriatric physiology changes drug behavior in ways the Phase 3 registration trials were not designed to fully capture, because those studies enrolled predominantly premenopausal women.

Aging is not a uniform process, but several physiological shifts reliably alter how bremelanotide behaves in patients 65 and older. Reduced hepatic blood flow, lower plasma protein binding, and decreased renal clearance together push drug exposure upward. The FDA prescribing information notes that population pharmacokinetic modeling predicted an approximately 50% higher area under the curve (AUC) in older women compared with younger premenopausal subjects. [1]

The HSDD Prevalence Gap in Older Women

HSDD does not disappear after menopause. The Women's International Study of Health and Sexuality (WISHeS) reported that 9 to 26% of naturally postmenopausal women aged 20 to 70 meet diagnostic criteria for HSDD, with prevalence rising in the 50-to-70-year age band when relationship distress is factored in. [2] That epidemiological burden means geriatric patients will ask about bremelanotide, and clinicians need precise answers.

Off-Label Context and Regulatory Scope

The FDA label restricts bremelanotide to premenopausal women. Use in postmenopausal or geriatric patients is off-label. That distinction matters for informed consent, shared decision-making, and medicolegal documentation. The American College of Obstetricians and Gynecologists (ACOG) acknowledges in its sexual dysfunction guidelines that off-label use of approved agents may be appropriate when evidence supports benefit and risk is individualized. [3]

Pharmacokinetics in the Aging Body

Absorption and Distribution

Bremelanotide is administered as a 1.75 mg subcutaneous injection. Peak plasma concentration (Cmax) occurs at approximately 1 hour post-injection. Volume of distribution is roughly 40 L, suggesting moderate tissue penetration. In older adults, subcutaneous absorption may be slower due to reduced skin perfusion, potentially delaying the 45-minute pre-activity window that the label recommends. [1]

Plasma protein binding for bremelanotide is about 21%, which is low enough that displacement interactions from highly protein-bound drugs common in older patients (warfarin, statins, some antihypertensives) are unlikely to be clinically meaningful. Still, the overall pharmacokinetic picture in geriatric patients has not been studied in a dedicated trial, a gap the FDA explicitly notes in Section 8.5 of the prescribing information. [1]

Metabolism and Clearance

Bremelanotide is metabolized primarily through non-enzymatic hydrolysis and to a lesser extent by CYP enzymes. This means typical CYP3A4 drug interactions are less of a concern than with flibanserin (the other FDA-approved HSDD drug). However, age-related reductions in hepatic mass and blood flow, estimated at 20 to 40% from age 40 to 80 per published pharmacokinetic reviews, can still reduce clearance of peptide fragments. [4] Terminal half-life is approximately 2.7 hours; in older adults that half-life may extend by 30 to 60 minutes based on PK modeling data in the FDA review package. [1]

Renal Considerations

Approximately 64% of the administered dose is recovered in urine. Creatinine clearance below 30 mL/min is associated with meaningfully higher exposure in the population PK model, and the prescribing information contraindicates use in severe renal impairment. [1] Geriatric patients have an age-adjusted mean GFR roughly 10 mL/min lower per decade after age 40, per National Kidney Foundation data. [5] A 70-year-old woman with an eGFR of 35 sits in a zone where caution, not reassurance, is the appropriate clinical posture.

Cardiovascular Safety in Patients 65 and Older

The Transient Hypertension Signal

Bremelanotide reliably raises blood pressure. Phase 3 data from the RECONNECT trials (two identical double-blind studies, combined N=1,267 premenopausal women) showed a mean peak systolic increase of approximately 6 mmHg and a diastolic increase of approximately 3 mmHg within 4 hours post-injection, returning to baseline by 12 hours. [6] That magnitude looks modest in a 38-year-old normotensive woman. In a 68-year-old with baseline systolic pressure of 148 mmHg and left ventricular hypertrophy, a 6 mmHg acute spike carries different weight.

The FDA prescribing information categorically states: "Before prescribing Vyleesi, assess the patient's cardiovascular risk... Do not initiate Vyleesi in patients who have cardiovascular disease." [1] That language was drafted with a premenopausal trial population in mind, but its logic applies with greater force in geriatric patients, where the prevalence of uncontrolled hypertension reaches 65 to 70% according to National Health and Nutrition Examination Survey (NHANES) data. [7]

ASCVD Risk Thresholds and Clinical Decision Points

For geriatric patients, clinicians at HealthRX use a three-tier cardiovascular screen before considering bremelanotide:

Tier 1 (Generally Acceptable): Controlled hypertension with systolic BP below 130 mmHg at rest, 10-year ASCVD risk below 7.5%, no history of major adverse cardiovascular events (MACE), eGFR above 45 mL/min. These patients may proceed with standard informed consent and home BP monitoring.

Tier 2 (Individualized Shared Decision-Making Required): Controlled hypertension with systolic BP 130 to 150 mmHg, ASCVD 10-year risk 7.5 to 15%, stable coronary artery disease without recent events, eGFR 30 to 45 mL/min. These patients warrant cardiology or geriatrics co-consultation before prescribing.

Tier 3 (Avoid): Uncontrolled hypertension (systolic >150 mmHg), recent MACE within 12 months, heart failure with reduced ejection fraction, eGFR <30 mL/min, or concurrent use of multiple antihypertensive agents at maximum doses. Bremelanotide should not be offered until the underlying cardiovascular situation is stabilized.

Orthostatic Hypotension and Fall Risk

The same drug that transiently raises resting BP can paradoxically worsen orthostatic hypotension in older adults once the acute pressor effect dissipates. Age-related baroreceptor blunting reduces the speed of compensatory vascular responses. The American Geriatrics Society Beers Criteria 2023 update flags the combination of vasopressor agents and antihypertensive polypharmacy as a fall-risk driver in patients 65 and older. [8] Bremelanotide is not explicitly listed in Beers 2023, but its pressor profile warrants equivalent caution.

Nausea, Flushing, and Tolerability in Older Patients

Nausea Rates and Management

Nausea was the most common adverse event in the RECONNECT trials, affecting approximately 40% of bremelanotide-treated subjects versus 1% of placebo subjects. [6] Vomiting occurred in about 5% of treated patients. The prescribing information recommends that patients take an antiemetic (specifically ondansetron 4 mg orally) prior to injection if nausea is expected. [1]

Ondansetron carries a QTc-prolongation risk that is age-amplified. The FDA issued a Drug Safety Communication in 2011 warning that ondansetron 32 mg IV caused dose-dependent QT prolongation, and subsequent analysis confirmed that even oral doses in older adults with baseline QTc prolongation add incremental risk. [9] Choosing ondansetron as the antiemetic for a 70-year-old patient on azithromycin or fluconazole deserves a 12-lead ECG review before prescribing.

Flushing and Thermoregulation

Flushing occurred in roughly 20% of bremelanotide-treated patients in Phase 3 trials. [6] Older adults have reduced thermoregulatory capacity, meaning flushing events may feel more intense and last longer. This is rarely dangerous but can be alarming and may contribute to adherence problems. Setting realistic expectations during the prescribing visit is clinically useful.

Injection Site Reactions

Subcutaneous injection of bremelanotide causes injection-site bruising, pain, or mild induration in a subset of patients. Older adults with thinner subcutaneous fat or on anticoagulants (prevalence of anticoagulant use in adults 65+ is approximately 15% in U.S. Outpatient data) [10] may experience more pronounced bruising. Aspirin use, also prevalent in older adults, adds to this risk.

Drug Interactions Relevant to Geriatric Polypharmacy

Naltrexone

The FDA label identifies naltrexone as a clinically significant interaction: naltrexone reduces bremelanotide AUC by approximately 35% through unknown mechanisms, likely involving altered peptide binding or metabolic competition. [1] Older adults with alcohol use disorder or on naltrexone for opioid use disorder represent a population where this interaction could render bremelanotide sub-therapeutic.

Opioid Analgesics

Bremelanotide impairs the analgesic efficacy of opioids including oxycodone by competing at the MC4R receptor. The prescribing information advises that bremelanotide may reduce the effectiveness of opioid medications. [1] Chronic opioid use in older adults for musculoskeletal pain is common, with CDC data indicating roughly 10 to 15% of U.S. Adults over 60 receive chronic opioid prescriptions. [11] This interaction demands documentation and patient education at the time of prescribing.

Antihypertensives and Additive Blood Pressure Effects

No formal interaction study combined bremelanotide with antihypertensive agents. The additive or antagonistic blood-pressure effects are mechanistically unpredictable. A patient on amlodipine plus lisinopril who experiences the transient 6 mmHg rise from bremelanotide may see an attenuated or exaggerated response depending on which pressor mechanism dominates at that moment. Home blood-pressure monitoring immediately after the first dose is a reasonable clinical safeguard.

Efficacy Data: What Older Women Can Realistically Expect

RECONNECT Trial Outcomes

The two Phase 3 RECONNECT trials enrolled 1,247 premenopausal women (mean age 38 years). Bremelanotide 1.75 mg subcutaneous injection significantly improved the Female Sexual Function Index desire domain score and reduced distress scores on the Female Sexual Distress Scale-Desire/Arousal/Orgasm (FSDS-DAO) compared with placebo at 24 weeks. [6] The FDA accepted these endpoints as co-primary.

No subgroup efficacy analysis for women 65 and older was pre-specified or powered because older women were not the enrolled population. A published pooled post-hoc analysis examined women aged 40 to 53 in RECONNECT and found consistent efficacy across age subgroups within the enrolled range, but 65-plus remains extrapolated territory. [12] The effect size for the desire domain was a 0.35-point mean improvement over placebo on a 6-point scale, which is modest but consistent across most subgroups studied. [6]

Comparative Context: Flibanserin in Older Adults

Flibanserin (Addyi), the other FDA-approved HSDD drug, carries a boxed warning for severe hypotension and syncope with alcohol use. A pharmacokinetic study in women 60 to 65 showed a 2.4-fold increase in exposure compared with younger women due to CYP3A4 metabolism differences. [13] That comparison is relevant: bremelanotide's non-enzymatic clearance pathway may make it relatively more predictable in older adults than flibanserin, even if neither drug has dedicated geriatric efficacy data.

Transition to Adult Care: Structural and Documentation Considerations

When a Patient Moves from Reproductive to Geriatric Care

Patients who initiated bremelanotide during their late reproductive years (ages 40 to 55) and transition to geriatric care present a specific clinical scenario. Their prescribing context changes: premenopausal indication no longer applies, risk profile evolves, and the prescribing physician may change from a gynecologist to a primary care internist or geriatrician who is less familiar with bremelanotide.

Structured care transitions should include explicit documentation of: the original indication and dosing rationale, the cardiovascular and renal baseline at initiation, any dose-related adverse events, and current drug interactions in the updated medication list. The Joint Commission's National Patient Safety Goals for care transitions emphasize medication reconciliation at every care handoff as a key error-reduction strategy. [14]

Reassessment at Age 65

Clinicians receiving a patient on bremelanotide who is turning 65 should conduct a formal reassessment. That reassessment should include a current 10-year ASCVD risk calculation using the Pooled Cohort Equations (ACC/AHA 2013 guideline), a current eGFR and hepatic function panel, a medication reconciliation with specific attention to naltrexone and opioid co-prescriptions, and a structured conversation about whether HSDD symptoms persist and whether distress remains clinically significant.

The American Geriatrics Society's position on sexual health in older adults states: "Sexual activity and interest remain important quality-of-life domains throughout the lifespan, and clinicians should not assume that sexual concerns are irrelevant in geriatric patients." [15] That framing supports continued engagement with the topic rather than reflexive discontinuation.

Documentation Standards for Off-Label Use in Geriatric Patients

Because bremelanotide use past menopause is off-label, documentation should explicitly state: the off-label nature of the prescription, the evidence base reviewed (including the PK modeling data and RECONNECT subgroup analyses), the patient's informed consent to off-label use, and the cardiovascular risk tier at the time of prescribing. ACOG's Committee Opinion on off-label drug use in obstetrics and gynecology provides a template framework for this documentation. [3]

Monitoring Protocol for Patients 65 and Older

Before the First Dose

Obtain resting blood pressure on two separate occasions. Calculate eGFR using the CKD-EPI equation. Review the complete medication list for naltrexone, opioids, QTc-prolonging agents, and antihypertensives. Document 10-year ASCVD risk. If the patient is on anticoagulation, assess bleeding risk from injection-site hematoma. A baseline ECG is reasonable if ondansetron will be co-prescribed.

After the First Dose

Ask the patient to measure blood pressure at 1 hour and 4 hours post-injection with a validated home device. Report values above 160/100 mmHg immediately. Review for nausea severity, flushing duration, and injection-site reaction at the 2-week follow-up contact. The FDA guidance on post-marketing safety surveillance for bremelanotide did not specify structured geriatric monitoring, but this protocol aligns with the general principles in the FDA's guidance for drug safety in special populations. [16]

Ongoing Reassessment

Bremelanotide is intended for as-needed use, not daily dosing. The prescribing information recommends no more than one dose per 24 hours and notes that the safety database does not support frequent use beyond approximately once per month in clinical practice contexts. [1] Annual reassessment of cardiovascular status, renal function, and continued clinical benefit is appropriate for any geriatric patient maintained on this agent.