{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Clearance II- Hepatic

Clearance II- Hepatic - Clearance II Hepatic...

Info iconThis preview shows pages 1–10. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Clearance II- Hepatic Continuous/Multiple Dosing Am ount Present versus Tim e Tim e 0 5 1 0 1 5 2 0 2 5 Amount Present 5 10 15 20 Ra = 4 %loss = 0.5 SS= 8 If beaker = 4 L then Cl = 4*0.5=2 L/min Ra = 4 %loss = 0.25 SS= 16 Quantitative Relationships • Amount reaches a steady state • Steady state depends on – Rate of Administration - R A – Rate of Excretion - R E • Clearance – proportionality constant • C pss,avg = R A / Cl T • Inverse – if clearance reduced, Css increases Clearance • Artificial – not really that x ml/min totally cleared • but mathematically behaves that way – (Gatorade example) • Fundamental – the body works this way • Moving fluids with known rates – R A = Cl * C pss, avg • Pharmacology determines Cp, • Cl determines administration rate Maintenance Dose • To maintain steady state – at SS R A = R E – R A = Cl * C pss, avg – R A = S*F*Dose/tau = Cl * C pss, avg – Therefore • Cl = [S*F*dose/tau]/C pss, avg • Dose = [Cl *C pss, avg *tau]/S*F Maintenance Dose • Infusion Rate – mass/time (mg/hr) – dose/tau (R A ) – if constant infusion can call is R • Maintenance Dose – required to produce desired C pss, avg • MD =Dose = [Cl *C pss, avg *tau]/S*F – iv infusion – tau is duration of infusion – (mg/hr for example) – Oral – tau is time between dosing* q6hr – (Note for oral dosing this is an approximation) Half-Life • Clearance determines wash out rate • Half-life – time for half to be cleared • t ½ = ln2*V d /Cl – ln 2 = 0.693 ~ 0.7 Factors affecting Cl • Body weight (size) • Renal and Hepatic Function – extraction ratio • Protein Binding • Cardiac Output Body Weight • Size • Function is proportional to size...
View Full Document

{[ snackBarMessage ]}

Page1 / 31

Clearance II- Hepatic - Clearance II Hepatic...

This preview shows document pages 1 - 10. Sign up to view the full document.

View Full Document Right Arrow Icon bookmark
Ask a homework question - tutors are online