PT-141 (Bremelanotide) Safety in Adults 65 and Older: What the Evidence Shows

What Is Bremelanotide and Why Geriatric Safety Deserves Its Own Analysis

Bremelanotide is a cyclic heptapeptide melanocortin receptor agonist that acts centrally at MC3R and MC4R receptors in the hypothalamus to increase sexual desire. The FDA approved it in June 2019 under the brand name Vyleesi for hypoactive sexual desire disorder (HSDD) in premenopausal women [1]. Clinicians prescribe it off-label for postmenopausal women and men with desire-related erectile dysfunction.

Sexual dysfunction does not end at 65. Prevalence data from the National Health and Social Life Survey extension cohort suggest that roughly 43% of women and 31% of men aged 57 to 85 report at least one significant sexual problem [2]. That population is growing, and prescribers are being asked about bremelanotide for older patients with increasing regularity.

The challenge: the RECONNECT phase 3 program enrolled premenopausal women with a mean age near 36 [3]. Adults aged 65 and older were not represented in meaningful numbers. Everything clinicians know about geriatric bremelanotide safety must therefore be assembled from pharmacokinetic modeling, the drug's known mechanism, post-marketing reports, and geriatric pharmacology principles.

How the Drug Works in Brief

Bremelanotide binds melanocortin receptors in the central nervous system rather than acting peripherally through vascular or hormonal pathways. That central mechanism means peripheral organ function matters primarily through drug clearance, not pharmacodynamics. Renal and hepatic function govern how long the drug lingers, which in turn governs how long its blood pressure effects and nausea persist.

The FDA Label's Position on Older Adults

The prescribing information states: "Clinical studies of Vyleesi did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects" [1]. No dose reduction is formally recommended based on age alone. The label does, however, restrict use in severe renal impairment and severe hepatic impairment, two conditions far more common in geriatric patients than in the trial population.

Cardiovascular Safety: Transient Hypertension in a Population That May Already Have High Blood Pressure

The most clinically significant acute risk from bremelanotide is a transient increase in blood pressure. In the RECONNECT trials (two double-blind, randomized controlled trials totaling approximately 1,247 women), systolic blood pressure rose a mean of 6 mmHg and diastolic blood pressure rose a mean of 3 mmHg, typically within 12 hours of injection [3]. That rise resolved without treatment in most participants.

For a healthy 36-year-old with normal baseline blood pressure, a 6 mmHg systolic bump is generally inconsequential. For a 70-year-old already on two antihypertensive agents with a resting systolic of 148 mmHg, the same increment may push them toward hypertensive urgency or trigger an adverse cardiac event.

Prevalence of Hypertension in Adults Aged 65 and Older

The CDC estimates that approximately 70% of U.S. Adults aged 65 and older have hypertension [4]. Prescribers considering bremelanotide in this age group must therefore treat the blood pressure question not as an edge case but as the default clinical scenario.

Which Patients Are at Greatest Cardiovascular Risk

The FDA label contraindicates bremelanotide in patients with cardiovascular disease that poses an unacceptable risk from transient blood pressure elevation [1]. In geriatric patients, that category includes:

• Uncontrolled hypertension (systolic above 150 mmHg despite medication)
• Recent myocardial infarction (within the prior 6 months)
• Unstable angina or class III/IV heart failure
• Significant arrhythmia requiring rate control

The prescriber should obtain a resting blood pressure measurement at baseline. Patients with controlled hypertension on stable regimens may be considered candidates, but they require explicit counseling to avoid dosing during periods of blood pressure instability.

Interaction with Antihypertensive Medications

Bremelanotide does not inhibit or induce the major cytochrome P450 enzymes at clinically relevant concentrations [1]. Its interaction with antihypertensives is therefore pharmacodynamic rather than pharmacokinetic. The transient BP elevation from bremelanotide theoretically opposes the effect of antihypertensives for several hours post-dose. Conversely, some vasodilatory antihypertensives (nitrates, alpha-blockers) could amplify the orthostatic hypotension that occasionally follows the peak hypertensive phase. Patients on alpha-blockers for benign prostatic hyperplasia, which is extremely common in older men using bremelanotide off-label, deserve specific counseling on standing slowly for 2 to 3 hours after injection.

Renal Function and Pharmacokinetic Changes in Older Adults

Bremelanotide is primarily eliminated through a combination of hydrolysis and renal excretion. The FDA label states that exposure (AUC) increases approximately 1.5-fold in patients with moderate renal impairment (eGFR 30 to 59 mL/min/1.73 m²) and warns against use in severe renal impairment (eGFR <30 mL/min/1.73 m²) [1].

Age-Related Decline in GFR

The National Kidney Foundation estimates that GFR declines at a rate of roughly 1 mL/min/1.73 m² per year after age 40 in the absence of kidney disease [5]. A 70-year-old with no diagnosed renal disease might have an eGFR of 55 to 65 mL/min/1.73 m², placing them squarely in the moderate impairment range for drug clearance purposes. That means bremelanotide will circulate longer, and its adverse effects, particularly nausea and blood pressure elevation, may last longer or feel more intense than in younger patients.

Practical Recommendations for Renal Assessment

Before prescribing bremelanotide to any patient aged 65 and older, clinicians should:

1. Obtain a current creatinine-based eGFR (CKD-EPI equation preferred)
2. Avoid use entirely if eGFR <30 mL/min/1.73 m²
3. Counsel patients with eGFR 30 to 59 mL/min/1.73 m² that nausea and cardiovascular effects may last longer than the label's described 12-hour window
4. Re-check renal function annually in ongoing users

Falls and Orthostatic Hypotension: A Geriatric-Specific Risk

Bremelanotide can cause dizziness and orthostatic hypotension, particularly in the hours following injection. In the RECONNECT trials, dizziness was reported in approximately 11% of bremelanotide-treated participants [3]. That number was derived from a younger, generally healthy population.

Falls are the leading cause of injury-related death in adults 65 and older, according to the CDC [6]. Any agent that causes dizziness or orthostatic changes carries disproportionate risk in this population. The American Geriatrics Society Beers Criteria, updated in 2023, flags drugs causing orthostatic hypotension as a specific category of concern in older adults [7].

Timing of the Dizziness Risk

Bremelanotide is dosed approximately 45 minutes before anticipated sexual activity. The blood pressure effects and associated dizziness peak within 2 to 4 hours of injection. Patients should be advised not to stand abruptly, not to climb stairs unassisted, and not to combine dosing with alcohol during that window.

Synergistic Fall Risk Factors in This Age Group

Many older adults take medications that independently raise fall risk: benzodiazepines, opioids, alpha-blockers, sedating antihistamines, and tricyclic antidepressants. Each one adds to the probability that a bremelanotide-induced orthostatic episode results in a fall. Clinicians should complete a fall-risk screening (the validated STEADI algorithm from the CDC is one option) before initiating bremelanotide in patients 65 and older [6].

Drug Interactions and Polypharmacy in the Geriatric Patient

Adults 65 and older in the United States take an average of 4.5 prescription medications simultaneously, according to data from the National Center for Health Statistics [8]. Bremelanotide's interaction profile is narrow but real.

Naltrexone and Opioid Receptor Considerations

The FDA label specifically warns that bremelanotide may reduce the systemic absorption and efficacy of co-administered oral medications because of drug-induced nausea and delayed gastric emptying [1]. Any oral medication with a narrow therapeutic index taken within 1 to 2 hours of a bremelanotide injection could be affected. Warfarin is one example of particular concern in geriatric patients. Levothyroxine is another. Patients on either drug should separate dosing by at least 2 hours or time bremelanotide when these agents have already been absorbed.

Bremelanotide is also contraindicated with naltrexone. Naltrexone is used to treat alcohol use disorder, which is underdiagnosed and underreported in older adults.

Serotonergic Medications

The mechanism of bremelanotide does not involve serotonin pathways directly, but clinicians using bremelanotide off-label alongside buspirone or other CNS-active agents for HSDD should be aware that combination CNS depression could worsen dizziness and sedation.

Medications That Raise Blood Pressure

NSAIDs, stimulant medications, and some decongestants can raise blood pressure independently. Combining any of these with bremelanotide could amplify the transient hypertensive effect. Older patients using NSAIDs chronically for arthritis pain represent a clinically common scenario that warrants explicit attention.

Nausea: The Most Common Side Effect and Its Geriatric Implications

Nausea occurred in 40.0% of bremelanotide-treated participants in the RECONNECT trials, compared with 1.3% of placebo-treated participants [3]. Vomiting affected approximately 4.7% of the treatment group. The prescribing information recommends injecting into the abdomen or thigh 45 minutes before activity and notes that nausea typically resolves within 1 hour [1].

Severe or prolonged nausea in an older adult carries risks beyond discomfort. Aspiration risk rises with repeated vomiting, particularly in patients with any degree of dysphagia. Dehydration from vomiting can precipitate acute kidney injury in a patient already operating with reduced renal reserve. Caloric avoidance around the time of dosing, which patients adopt to reduce nausea, could cause hypoglycemia in diabetic patients on insulin or sulfonylureas.

Managing Nausea in Geriatric Patients

Prescribers should consider the following strategies for older patients:

• Advise a light meal 1 to 2 hours before injection (eating immediately before or after worsens nausea)
• Avoid alcohol on the day of dosing
• Have a short-acting antiemetic available (ondansetron 4 mg orally as needed) but note that ondansetron can prolong the QT interval, which matters in patients already on QT-prolonging medications
• If nausea is severe on the first dose, reassess whether the benefit-risk ratio justifies continued use

Hepatic Function and Its Role in Bremelanotide Clearance

The FDA label contraindicates bremelanotide in severe hepatic impairment [1]. In mild to moderate hepatic impairment, no dose adjustment is required, but the pharmacokinetic data supporting that conclusion come from small dedicated PK studies rather than geriatric-specific clinical trial experience.

Older adults are more likely to have non-alcoholic fatty liver disease, alcohol-related hepatic changes, or medication-induced hepatic injury than younger populations. A baseline liver function panel is a reasonable precaution before initiating bremelanotide in patients with any hepatic risk factors, including obesity, heavy alcohol use, or long-term NSAID exposure.

Sexual Desire in Older Adults: The Clinical Context for Prescribing

HSDD, now reconceptualized as female sexual interest/arousal disorder (FSIAD) in the DSM-5, affects an estimated 8 to 10% of women across the lifespan when distress is required for diagnosis [9]. In postmenopausal women, co-occurring genitourinary syndrome of menopause (GSM), depression, relationship factors, and medication side effects often contribute to low desire alongside any primary desire disorder.

Bremelanotide is approved only for premenopausal women. Its use in postmenopausal women is off-label, and the evidence base is limited. The North American Menopause Society (NAMS) 2022 position statement on sexual health notes that hormonal therapies remain first-line for desire concerns in postmenopausal women before non-hormonal options are considered [10].

A Geriatric Prescribing Decision Framework for Bremelanotide

Before initiating bremelanotide in a patient aged 65 or older, each of the following gates should be addressed:

Gate 1: Cardiovascular screen. Resting blood pressure <150/90 mmHg on current medications. No unstable cardiovascular disease. Review current antihypertensive list for alpha-blocker use.

Gate 2: Renal screen. eGFR at or above 30 mL/min/1.73 m². If eGFR is 30 to 59, document informed consent that adverse effects may last longer.

Gate 3: Fall-risk screen. STEADI algorithm completed. If fall risk is moderate to high, consider whether the orthostatic risk is acceptable.

Gate 4: Polypharmacy review. Identify narrow-therapeutic-index oral medications taken within 2 hours of likely bremelanotide use. Identify any naltrexone use. Identify chronic NSAID use.

Gate 5: Hepatic screen. LFTs if any hepatic risk factors present. Avoid if Child-Pugh C.

Gate 6: Shared decision-making. The patient understands that nausea is likely (40% incidence), that the blood pressure effect is real, and that the drug is off-label in postmenopausal women. Document that discussion.

What the RECONNECT Trials Tell Us (and What They Don't)

The RECONNECT program consisted of two identically designed phase 3, randomized, double-blind, placebo-controlled trials published in Obstetrics and Gynecology in 2019 [3]. Combined, the studies enrolled 1,247 premenopausal women aged 18 to 50. Participants received either bremelanotide 1.75 mg subcutaneously or placebo as needed over 24 weeks.

The primary endpoints were changes from baseline in the desire domain of the Female Sexual Function Index (FSFI-d) and the Female Sexual Distress Scale-Desire/Arousal/Orgasm (FSDS-DAO) item 13. Bremelanotide produced statistically significant improvements on both measures compared with placebo (P<0.001 for both co-primary endpoints) [3].

What the trials cannot tell us: anything about pharmacokinetics in patients older than 50, anything about interaction with the medication burden typical of a 70-year-old, and anything about blood pressure trajectory in a patient who begins the study with hypertension. The geriatric prescriber is, by necessity, extrapolating.

The mean age of participants in RECONNECT was approximately 36 years. The oldest enrolled participant was 50. That 15-year gap between the maximum trial age and the start of the geriatric bracket is not trivial from a physiologic standpoint.

Post-Marketing Safety Data and Pharmacovigilance Signals

The FDA Adverse Event Reporting System (FAERS) database has accumulated bremelanotide reports since the 2019 approval. As of the most recent public data release, nausea, flushing, and injection-site reactions remain the most commonly reported adverse events, consistent with the trial profile [11].

Hypotension and syncope reports exist in FAERS, though causality assessment in spontaneous reports is inherently limited. Prescribers should report any serious adverse events in older patients directly to MedWatch, as geriatric post-marketing data represent the primary mechanism by which the safety profile in this age group will eventually be characterized.

Practical Dosing Guidance for Older Adults

The standard dose is 1.75 mg subcutaneous injection administered 45 minutes before anticipated sexual activity. Use is limited to one injection per 24-hour period and should not exceed one injection per event [1].

No reduced starting dose for geriatric patients is formally studied or FDA-recommended. A reasonable clinical approach for patients with moderate renal impairment or elevated cardiovascular risk is to have the first dose administered in a setting where blood pressure can be monitored for 2 hours afterward. That could be a clinic visit or a home setting with a reliable blood pressure cuff and a caregiver present.

Injection sites are the abdomen or thigh. Rotating sites reduces localized reactions. Older adults with reduced dexterity or visual impairment may need assistance preparing and administering the autoinjector.