KINE 2475 Chapter Notes - Chapter 5.8: Hypotension, Catabolism, Thrombocytopenia
Types of pd5i: sildenafil (viagra) - greatest ba, tadalafil (cialis) - greatest half-life, longer lasting, vardenafil (levitra/staxyn, avanafil (stendra) Efficacy of pd5i: response rates lower in patients w/diabetes mellitus or prostatectomy, vascular disease, neuropathy or surgery, sil & var on empty stomach. 2 hours before meals for faster response: tadalafil & avanafil can be taken w or w/o meals, must take 5-8 doses before increasing. In older patients with onset hypogonadism & ed, corrected with testosterone supplementations improves response to pd5i. Pharmacokinetics & drug-food interactions: sil & var have similar pk. 1 hr onset & short duration of action. Ba is low when taken with food: tada has slow onset (2hrs), prolonged duration (36hrs), food doesn"t affect absorption, avanafil has onset of 15mins. Food doesn"t affect absorption: cocomitant ingestion of ethanol w/pd5i results in orthostatic hypotension & drowsiness, avoid alcohol, hepatically catabolized by p450/3a4.