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PDE5 Inhibitors

Tips for Improved Efficacy

• Use 9-10 times before increasing dose
• Increased dose increases side effects but not efficacy
• Sexual stimulation required
• No evidence that early use helps regain erections after prostatectomy
• Overall 70% report success with sexual intercourse, only 40-50% if diabetic

Risks/Contraindications

• Contraindications: nitrates, severe liver/renal disease
• Relative contraindications: baseline hypotension or hypertension, drugs that increase PDE5i halflife (Cyp-P450 3A4 inhibitors), retinitis pigmentosa, cardiovascular disease
• a-blockers + PDE5i: okay to use but increased risk for hypotension
• nitrates + PDE5i: no pharmacologic antidote if co-administered
• Hypotension management: fluids, a-agonists, Trendelenburg position, rarely requires intraaortic balloon pump
• Cross-reactions: antidepressants, antifungals, antiHTN, HAART
• Common side effects: dyspepsia (4-10%), headache (7-16%), flushing (4-10%), myalgia + back pain (0-3%, congestion (3-4%), visual disturbances (0-3%)
• Blue/green color vision change: due to PDE6 cross-reactivity, not seen with tadalafil
• Sudden unilateral vision loss (NAION): overall extremely rare (3/100K), possibly not even a real association

Options

Drug	Dosing	Onset	Avoid with fatty food	Headache/Dyspepsia/Flushing	Backache/Myalgias	Blurred/Blue Vision
Sildenafil (Viagra)	25-100mg	30-60min	Yes	Yes	Rare	Yes
Tadalafil (Cialis)	5-20mg	60-120min	No	Yes	Yes	Rare
Vardenafil (Levitra)	5-20mg	30-60min	Yes	Yes	Rare	Rare

Other Non-Surgical Treatment Options

Lifestyle changes

• General tips: maintain ideal weight, exercise
• Drug use: stop smoking, alcohol, and other drug use
• Medications: stop or switch to medications with lower ED risk
• Comorbidities: optimize HTN, DM, cardiac disease
• Psychogenic ED: consider sexual counseling

Intracavernosal Injections

• Options: alprostadil (cAMP stimulator), papaverine (non-specific PDEi), phentolamine (a1-blocker), atropine, bimix (papaverine + phentolamine), trimix (bimix + alprostadil)
• Efficacy: 54-100%, satisfaction 46-99%
• Side effects: priapism (highest with papaverine), pain (highest with alprostadil), fibrosis (highest with papaverine), hypotension and systemic side effects (highest with veno-occlusive leak)
• Contraindications: hx pripaism, coagulopathy, unstable cardiac disease, reduced manual dexterity, MAOi use (HTN crisis if a-agonist needed to reverse a priapism)
• Anticoagulation: not a contraindication, hold pressure to prevent hematoma
• Dosing: alprostadil (2.5-60ug/mL), bimix (20ug/mL + 0.5mg/mL), trimix (10ug/mL + 30mg/mL + 1mg/mL), maximum 3x weekly with > 24hr between doses

Vacuum Assist Device + Occlusion ring

• Satisfaction: patient (60-80%), partner (70+%)
• Weak seal: trim pubic hair and use adequate lubricant
• Abnormal sensation: may create fulcrum effect (flaccid proximal, rigid distal) or abnormal feel/appearance (blue/gray color, cool to touch)
• Side effects: bruising (18%), pain (18%), difficult ejaculation (22%), device difficulty (20%)
• Contraindications: priapism risk, penile fibrosis, bleeding disorder or anticoagulation (can cause hematoma)
• Frequency: do not use for > 30min, wait at least 1hr between uses

Intraurethral Alprostadil (MUSE)

• Dosing: 125, 250, 500, 1000 mcg
• Directions: urinate before use, insert pill/applicator, roll penis to dissolve medication, use maximum BID, test in office prior to prescribing (2% risk hypotension)
• Efficacy: 50-70%
• Side effects: genital pain (6.5-35%), urethral trauma (1-5%), urethral pain (0-29%), dizziness (0-7%), painful erection (1%), potential risk for priapism
• Contraindications: high risk for priapism, distal urethral stricture, penile fibrosis, balanitis, urethritis, having sex with pregnant woman (unless using condom)

Testosterone therapy (see separate page)

• Do not supplement testosterone if normal T levels
• Baseline assessment: DRE, PSA, CBC, LFT, lipids, repeat 3-6mo after starting treatment, then annually
• Give short course testosterone (3mo), if no improvement then discontinue
• Common side effects: increased Hgb, OSA, gynecomastia, acne

Arterial revascularization

• Indications: only patients with proven arterial insufficiency, usually focal stenosis from trauma
• Contraindications: atherosclerosis, veno-occlusive disease, tobacco use
• Procedure: anastomose inferior epigastric to dorsal penile artery or deep dorsal penile vein, can cause glans hyperemia, success rates 60-70% at 5yr

Penile Prosthesis

See separate page for counseling, techniques, and postoperative troubleshooting