What medical conditions and medications should be screened for in a patient with a history of cardiovascular disease, diabetes, or hypertension before prescribing Viagra (sildenafil)?

Pre-Viagra Screening Essentials

Before prescribing Viagra (sildenafil) to any patient—especially those with cardiovascular disease, diabetes, or hypertension—you must screen for nitrate use (absolute contraindication), assess cardiovascular risk stratification, and verify the patient can tolerate moderate physical activity equivalent to walking 1 mile in 20 minutes or climbing 2 flights of stairs. 1, 2

Absolute Contraindications to Screen For

Nitrate Use (Any Form)

• Never prescribe sildenafil with nitrates—this combination causes potentially fatal hypotension 1, 2
• Explicitly ask about:
  • Nitroglycerin (tablets, patches, sprays, ointments) 2
  • Isosorbide mononitrate or dinitrate 2
  • Recreational "poppers" (amyl nitrate/nitrite) 2
• If uncertain about a medication, verify before prescribing 2

Other Absolute Contraindications

• Severe hepatic impairment 1
• Hereditary degenerative retinal disorders (e.g., retinitis pigmentosa) 1, 2
• Recent stroke or myocardial infarction (within 2 weeks) 1
• Hypotension (BP <90/50 mmHg) 2

Cardiovascular Risk Stratification (Princeton Consensus)

High-Risk Patients (Defer ED Treatment Until Stabilized) 1

• Unstable or refractory angina
• Uncontrolled hypertension
• Recent MI or stroke (within 2 weeks)
• NYHA Class II-IV heart failure
• High-risk arrhythmias
• Hypertrophic obstructive cardiomyopathy
• Moderate-to-severe valvular disease

Low-Risk Patients (Safe for Sildenafil) 1, 3

• Asymptomatic coronary artery disease with <3 risk factors (excluding gender)
• Controlled hypertension
• Mild, stable angina
• Successful coronary revascularization
• Uncomplicated past MI
• Mild valvular disease
• NYHA Class I heart failure

Indeterminate Risk (Refer to Cardiology First) 1

• Patients who cannot perform moderate physical activity without symptoms
• Those unable to walk 1 mile in 20 minutes or climb 2 flights of stairs 3, 4

Medical History Screening

Cardiovascular Conditions 1

• Hypertension (controlled vs. uncontrolled)
• Atherosclerosis or hyperlipidemia
• History of MI, stroke, or heart failure
• Angina (stable vs. unstable)
• Arrhythmias

Metabolic and Endocrine Disorders 1

• Diabetes mellitus (associated with more severe ED and reduced treatment response) 5, 3
• Obesity
• Hypogonadism (consider testosterone measurement if clinically indicated) 1

Other Medical Conditions 1, 2

• Depression or psychiatric disorders
• Neurologic disease
• Pelvic/perineal/penile trauma or surgery
• Peyronie's disease
• Blood cell disorders (sickle cell anemia)
• Bleeding disorders or active peptic ulceration 2
• Renal impairment (creatinine clearance <30 mL/min increases sildenafil levels) 6

Ophthalmologic History 2

• Previous NAION (non-arteritic anterior ischemic optic neuropathy) in one eye
• Risk factors for NAION: age >50, diabetes, hypertension, coronary artery disease, hyperlipidemia, smoking, "crowded disc" (low cup-to-disc ratio)

Medication Review

Current Antihypertensive Medications 1, 4, 2

• Beta-blockers (can worsen ED; nebivolol preferred if beta-blocker needed) 4
• Thiazide diuretics (associated with higher ED rates) 4, 7
• Aldosterone antagonists like spironolactone (can worsen ED) 4, 7
• ARBs are optimal for men with ED (may improve erectile function) 4
• Monitor blood pressure when combining sildenafil with antihypertensives 2

Other Medications That Interact or Cause ED 1, 6

• SSRIs (can impair sexual function) 1
• CYP3A4 inhibitors increase sildenafil levels: erythromycin, ketoconazole, itraconazole, ritonavir, cimetidine 6
• PDE3 inhibitors (milrinone, enoximone) - use with caution 6
• Anticoagulants (increased risk of epistaxis and hemorrhage with sildenafil) 2

Physical Examination

Focused Cardiovascular and Genital Exam 1

• Blood pressure measurement (identify hypotension or uncontrolled hypertension) 1
• Examination of genitalia (testicular size, penile abnormalities, Peyronie's disease, retractable foreskin) 1
• Lower extremity pulses 1
• Secondary sexual characteristics 1
• Abdominal examination 1

Laboratory Testing

Mandatory for All Patients 1

• Fasting plasma glucose or HbA1c (screen for diabetes) 1

Conditional Testing 1

• Morning total testosterone (if hypogonadism suspected clinically) 1
• Luteinizing hormone and prolactin (only if testosterone low or loss of libido) 1
• Creatinine and electrolytes (if renal impairment suspected) 1
• Liver function tests (if hepatic disorder suspected) 1
• Lipid panel (if dyslipidemia suspected) 1
• PSA and digital rectal exam (men >50 with >10 year life expectancy, especially if considering testosterone) 1

Functional Capacity Assessment

Exercise Tolerance Screening 3, 4, 8, 6

• Ask: "Can you walk 1 mile in 20 minutes without symptoms?" 3, 4
• Ask: "Can you climb 2 flights of stairs in 20 seconds without symptoms?" 3, 4
• Sexual activity requires approximately 3-5 METs (metabolic equivalents) 1, 8, 6
• If patient cannot perform this level of activity, refer to cardiology before prescribing 1, 3

Common Pitfalls to Avoid

Failure to Ask About Nitrates

• Patients may not volunteer this information 2
• Always explicitly ask about all forms of nitrates, including recreational drugs 2

Underestimating Cardiovascular Risk

• ED itself is a strong independent marker for cardiovascular disease, equivalent to smoking or family history of MI 4
• Erectile dysfunction and cardiovascular disease share common endothelial dysfunction pathophysiology 1, 9

Not Screening for Diabetes

• Diabetes causes more severe ED and reduces treatment response 5, 3, 9
• All patients should have glucose screening before starting sildenafil 1

Ignoring Medication-Induced ED

• Many antihypertensives, antidepressants, and other drugs cause or worsen ED 1, 7
• Consider switching to ED-friendly alternatives (e.g., ARBs instead of beta-blockers) before adding sildenafil 4

Overlooking Partner and Relationship Issues

• Partner's sexual function and relationship quality affect treatment success 1
• Psychosexual factors may require concurrent management 1