• asymptomatic and have less than 3 risk factors for coronary artery disease (CAD, excluding gender).
• controlled hypertension, mild valvular disease, and left ventricular dysfunction/congestive heart failure (LVD/CHF, New York Heart Association [NYHA] class I and II).
• had successful coronary revascularisation (for example via coronary artery bypass grafting, stenting, or angioplasty). 
• implied by the ability to perform exercise of modest intensity without symptoms. 

• GP
• No not need for testing or evaluation before the resumption of sexual activity 

• Three or more risk factors for CAD (excluding gender).
• Mild or moderate stable angina.
• Past myocardial infarction (MI, within the last 2–8 weeks) without intervention awaiting exercise electrocardiography.
• LVD/CHF (NYHA class III).
• Noncardiac sequelae of atherosclerotic disease (for example peripheral vascular disease and a history of stroke or transient ischemic attack). 

• Specialist testing or evaluation is recommended before the resumption of sexual activity

• Unstable or refractory angina.
• Uncontrolled hypertension.
• LVD/CHF (NYHA class IV).
• Recent MI without intervention (within the last 2 weeks).
• High-risk arrhythmia (exercise-induced ventricular tachycardia, implanted internal cardioverter defibrillator with frequent shocks, and poorly controlled atrial fibrillation).
• Obstructive hypertrophic cardiomyopathy with severe symptoms.
• Moderate to severe valve disease (particularly aortic stenosis).
• Loss of vision in one eye because of non-arteritic anterior ischaemic optic neuropathy (NAION), regardless of whether this episode was in connection or not with previous PDE5 inhibitor exposure.

• Referr for cardiac assessment and treatment.
• Sexual activity should be stopped until the cardiac condition has been stabilized by treatment, or a decision made by the cardiologist that it is safe to resume sexual activity

Nitrates 

• They result in cyclic guanosine monophosphate (cGMP) accumulation and unpredictable falls in blood pressure and symptoms of hypotension. The duration of interaction between organic nitrates and PDE-5 inhibitors depends on the PDE-5 inhibitor and nitrate used.
• If a PDE-5 inhibitor is taken and the man develops chest pain, organic nitrates should not be used for at least 24 hours for sildenafil and possibly vardenafil (half-life 4 hours), 48 hours for tadalafil (due to its longer half-life of 17.5 hours), and at least 12 hours for avanafil (half-life 6–17 hours).

•  concurrent treatment with a PDE-5 inhibitor and an alpha-blocker can increase the risk of postural hypotension as both are vasodilators. 
  • PDE-5 inhibitors should not be used by men taking non-selective alpha blockers (such as doxazosin, indoramin, terazosin, or prazosin) unless they have finished alpha-blocker dose titration and are on a stable dose. The manufacturers also state that:
    • Sildenafil should be used with caution in men taking an alpha-blocker (especially doxazosin). Hypotension is more likely to occur within four hours following treatment with an alpha-blocker. A sildenafil starting dose of 25 mg is recommended [ABPI, 2016a].
    • Vardenafil should be initiated at the lowest starting dose of 5 mg (if the man has been stabilised on his alpha-blocker treatment). Vardenafil may be given at any time with tamsulosin or alfuzosin but with other alpha-blockers, a time separation of dosing should be considered. In men already taking an optimized dose of vardenafil, alpha-blocker treatment should be initiated at the lowest dose [ABPI, 2017c]. 
    • Tadalafil is not recommended in men taking doxazosin (due to a significant blood pressure lowering effect). For all other alpha-blockers, tadalafil should be used with caution; treatment should be initiated at minimal dosage and progressively adjusted [ABPI, 2017b]. 
    • Avanafil should be initiated at the lowest dose of 50 mg. Conversely in men already taking an optimal dose of avanafil, alpha-blocker treatment should be initiated at the lowest dose [ABPI, 2016b].

• may reduce the clearance of PDE-5 inhibitors, as PDE-5 inhibitors are metabolized by this enzyme.
  • Sildenafil 
    • With ritonavir — co-administration should be avoided if possible, otherwise a maximum dose of 25 mg of sildenafil within 48 hours must not be exceeded.
    • With all other CYP3A4 inhibitors (such as ketoconazole, itraconazole, erythromycin, cimetidine, and grapefruit juice) — a sildenafil starting dose of 25 mg should be considered.
  • Vardenafil
    • HIV protease inhibitors (such as ritonavir and indinavir; very potent inhibitors of CYP3A4) — co-administration is contraindicated.
    • Potent CYP3A4 inhibitors (such as clarithromycin and oral ketoconazole and itraconazole) — co-administration is contraindicated in men older than 75 years and should be avoided in all other men.
    • Moderate CYP3A4 inhibitors (such as erythromycin) — vardenafil dose adjustment may be necessary.
    • Grapefruit — co-administration should be avoided as concomitant intake of grapefruit or grapefruit juice is expected to increase the plasma concentrations of vardenafil.
  • Tadalafil 
    • Co-administration with CYP3A4 should be avoided if possible, otherwise tadalafil should be initiated at the lowest recommended starting dose.
  • Avanafil
    • Very potent and potent CYP3A4 inhibitors (such as itraconazole, clarithromycin, saquinavir, and indinavir) — co-administration is contraindicated.
    • Moderate CYP3A4 inhibitors (such as erythromycin) — a maximum dose of 100 mg of avanafil within 48 hours must not be exceeded.
    • Other CYP3A4 inhibitors — co-administration should be done with caution. 
    • Grapefruit — the man should be advised to avoid grapefruit juice within 24 hours prior to taking avanafil.

• Co-administration should be avoided if possible, otherwise, higher doses of the PDE-5 inhibitor may be required.

• eGFR < 30 initial dose 25 mg - can be increased to 50 mg, then 100 mg
• No dose adjustment if mild to moderate 

• mild to moderate start dose of 25 mg
• can be increased upto 100mg 
• avoid in severe 

20mg

• eGFR < 30 max dose 10 mg.
• No dose adjustment if mild to moderate 

• benefit/risk evaluation
• max 10 mg
• if severe use with caution

• Avoid

•  Use with caution

• eGFR < 30 start dose 5mg upto 20mg 
• No dose adjustment if mild to moderate 

• start with 5 mg for mild to moderate upto max 10 mg
• if severe use with caution

No dose adjustment is needed

Avoid max dose

• eGFR < 30 start dose 5mg upto 20mg 
• No dose adjustment if mild to moderate 

• mild- start with 5 mg film-coated tablets. upto 20 mg film-coated tablets, or vardenafil 10 mg orodispersible tablets.
• Do not use vardenafil orodispersible tablet as a starting dose in any level of hepatic impairment.

Dose adjustments are not required.

Avoid max dose

• eGFR < 30Avoid
• No dose adjustment if mild to moderate 

• Do not use avanafil in men with severe hepatic impairment. 
• In men with mild to moderate hepatic impairment, use the lowest effective initial dose and adjust according to response.

No dose adjustment is needed.

Limited data for its use in men aged 70 years and older.