Cyclic, 7 residues

PT-141 (bremelanotide)

FDA-approved melanocortin receptor agonist (Vyleesi) for low sexual desire in premenopausal women

1.75MG

Dose

17.5U

Draw

30D

Cycle

Bremelanotide is approved in the US as Vyleesi for premenopausal women with acquired, generalized hypoactive sexual desire disorder. It is not indicated for postmenopausal women or for men. The label product is a single-dose prefilled autoinjector, not a lyophilized vial.

Protocols

Label use before sexual activityrecommended
Reproduces the Vyleesi label dose. Contraindicated with uncontrolled hypertension or known cardiovascular disease (label). Inject at least 45 minutes beforehand.

Dosing

Label: 1.75 mg subcutaneously (abdomen or thigh), as needed, at least 45 minutes before anticipated sexual activity.
Label: no more than one dose within 24 hours; more than 8 doses per month is not recommended.

Route & timing

Route: Subcutaneous, into the abdomen or thigh (label: self-administered with a prefilled autoinjector pen).

Timing: At least 45 minutes before anticipated sexual activity, as needed (label).

Reconstitution

The label product is a ready-made 1.75 mg/0.3 mL solution: nothing to reconstitute. The water in the protocol is arithmetic for a readable draw from a lyophilized vial (10 mg + 1 mL gives 1.75 mg = 17.5 units), not a sourced instruction.

Reconstitution calculator

Vial amount (mg)Water (mL)Dose (mg)

Concentration: 10 mg/mL
Per unit: 0.1 mg
Draw: 17.5 units
Volume: 0.175 mL
Doses per vial: 5.71
Vials for cycle (8 doses), pooled: 2
Vials, discard remainder: 2

concentration = 10 / 1 = 10 mg/mL

per unit = 10 / 100 = 0.1 mg

units = 1.75 / 0.1 = 17.5

mL = 17.5 / 100 = 0.175

doses per vial = 10 / 1.75 = 5.714

pooled vials = ceil(1.75 x 8 / 10) = 2

discard vials = ceil(8 / floor(5.714)) = 2

Stability

No reliable figure found in the sources; ask your prescriber or supplier.

Off-cycle

No cycle: used as needed, with at most 8 doses per month (label).

Why:

More frequent dosing raises the risk of focal hyperpigmentation and lengthens the time blood pressure is raised (label).

Stacking rules

Never draw into the same syringe as another compound; use separate syringes and distinct injection sites.
Label: may slow gastric emptying and affect absorption of oral medicines; may significantly lower exposure to oral naltrexone, so avoid that combination.

Safety

FDA-approved (2019) for the indication above. Vials sold outside a pharmacy are unapproved and unverified.

Common side effects:

Nausea in about 40% of patients in the phase 3 trials (anti-emetic needed in 13%, 8% stopped because of it); it tends to improve with the second dose (label).
Flushing (about 20%), headache (11%), vomiting and injection-site reactions (label).
Transient blood pressure rise (up to about 6 mmHg systolic, 3 diastolic, peaking 2-4 hours after the dose) and a small fall in heart rate; back to baseline usually within 12 hours (label).
Focal hyperpigmentation (face, gums, breasts): 1% with up to 8 doses a month; 38% in a study with daily dosing for 8 days. More likely with dark skin, and not always resolved after stopping (label).

Stop and call your prescriber if:

Persistent or severe nausea
New dark patches on the skin, gums or breasts
Chest pain, palpitations or a severe headache

Markers to track

What sources report this compound changes, or say to check. A record of the evidence, not targets or advice.

Blood pressureCheck itDrug label
Transient rise after each dose: up to 6 mmHg systolic and 3 mmHg diastolic, peaking 2-4 h, back to baseline usually within 12 h; label advises ensuring BP is well controlled
FDA Vyleesi (bremelanotide) prescribing information
Heart rateReported changeDrug label
Transient reduction of up to 5 beats per minute after dosing, returning to baseline usually within 12 h
FDA Vyleesi (bremelanotide) prescribing information

Sources

FDA Vyleesi (bremelanotide) prescribing information: dose, limits, warnings, adverse reactions