ClinCalc Pro
Menu
Calculators Drugs Pathways AI Dx Donate Get the App
Phosphodiesterase Type 5 (PDE5) Inhibitor (Erectile Dysfunction)

Avanafil

Brand names: Spedra

Adult dose

Dose: 100 mg 15–30 minutes before sexual activity; may be reduced to 50 mg or increased to 200 mg based on response
Route: Oral
Frequency: As needed (not more than once daily)

Clinical pearls

  • Fastest onset of all licensed PDE5 inhibitors — effective within 15–30 minutes (versus 30–60 for sildenafil/tadalafil)
  • NICE CKS: PDE5 inhibitors are first-line for erectile dysfunction; NICE does not routinely fund on NHS except in specific conditions (diabetes, prostate surgery, MS, renal failure, etc.)
  • High selectivity for PDE5 over PDE6 (retinal) — potentially fewer visual side effects
  • As with all PDE5 inhibitors: sexual stimulation required — not pro-erectile alone
  • NICE guidance on NHS funding: GPs may prescribe on FP10 for specific conditions; private prescription otherwise

Contraindications

  • Nitrates (organic nitrates or nitric oxide donors) — profound hypotension; absolutely contraindicated
  • Severe hepatic impairment
  • Recent stroke, MI, or life-threatening arrhythmia
  • Severe cardiovascular disease
  • Hypotension (BP <90/50 mmHg)
  • Retinitis pigmentosa
  • Concomitant alpha-blockers (caution; not absolute if appropriately dosed)

Side effects

  • Headache
  • Flushing
  • Nasal congestion
  • Back pain, myalgia (class PDE5 effect)
  • Visual disturbances (rare — non-arteritic ischaemic optic neuropathy)
  • Priapism (rare)

Interactions

  • Nitrates — absolute contraindication: severe, potentially fatal hypotension
  • Alpha-blockers — additive hypotension; caution required; start avanafil at 50 mg and separate doses
  • CYP3A4 inhibitors (itraconazole, ritonavir, clarithromycin) — markedly increased avanafil levels; contraindicated with potent inhibitors
  • Antihypertensives — additive hypotension

Monitoring

  • Efficacy (IIEF score)
  • Cardiovascular fitness for sexual activity
  • Avoid if recent cardiovascular event until cardiologically stable

Reference: BNF; NICE CKS Erectile dysfunction (2023); EAU Guidelines on Sexual and Reproductive Health (2024); https://bnf.nice.org.uk/drugs/avanafil/. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

Calculators
Pathways