This is a Phase 2, open-label, randomized crossover study assessing the effect of moderate alcohol intake on the absorption and onset of action of Hezkue® sildenafil oral suspension in adult subjects. Participants will receive Hezkue® under different alcohol intake conditions in randomized sequence. Pharmacokinetic sampling and onset assessments will be performed after each administration, and safety will be monitored throughout the study.

Inclusion Criteria:

• Male adults 21 to 65 years of age, inclusive
• Documented history of erectile dysfunction for at least 6 months, as determined by the investigator
• In a stable sexual relationship and willing to attempt sexual activity as required by study procedures, if applicable
• Medically stable based on medical history, physical examination, vital signs, 12-lead ECG, and clinical laboratory evaluations, in the opinion of the investigator
• Able, in the investigator's judgment, to safely consume moderate amounts of alcohol as defined in the protocol
• Willing to abstain from alcohol outside of protocol-specified intake during the study
• Able to understand and provide written informed consent before any study-specific procedures are performed
• Willing and able to comply with all study procedures, including dosing, washout periods, pharmacokinetic sampling, onset assessments, and safety monitoring

Exclusion Criteria:

• Known hypersensitivity or contraindication to sildenafil, other PDE5 inhibitors, alcohol, or any component of the Hezkue® formulation
• Use of nitrates, nitric oxide donors, guanylate cyclase stimulators (such as riociguat), or other prohibited medications within a protocol-defined period
• Clinically significant cardiovascular disease, including coronary artery disease, heart failure, clinically important arrhythmias, recent stroke, or uncontrolled hypertension or hypotension
• Resting blood pressure or heart rate outside protocol-defined acceptable ranges at screening or baseline, in the opinion of the investigator
• Significant hepatic, renal, neurologic, psychiatric, endocrine, hematologic, or respiratory disease that could increase risk or interfere with study assessments
• History of syncope, significant orthostatic hypotension, or other conditions that may be worsened by sildenafil or alcohol
• History of alcohol use disorder, binge drinking, or other substance use disorder, as determined by the investigator
• Positive urine drug screen or positive alcohol test at screening or admission (outside protocol-specified alcohol administration)
• Use of prescription or over-the-counter medications, herbal products, or dietary supplements within 14 days before first dosing unless approved by the investigator
• Positive test for hepatitis B surface antigen, hepatitis C antibody, or HIV
• Participation in another clinical study or receipt of an investigational product within 30 days or 5 half-lives, whichever is longer
• Donation of 450 mL or more of blood, or significant blood loss, within 8 weeks before first dosing
• Any condition or circumstance that, in the opinion of the investigator, would make the participant unsuitable or interfere with study conduct or interpretation