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In pharmacokinetics, the rate of infusion (or dosing rate) refers not just to the rate at which a drug is administered, but the desired rate at which a drug should be administered to achieve a steady state of a fixed dose which has been demonstrated to be therapeutically effective.

Abbreviations include K_in, ^[1] K₀, ^[2] or R₀.

It can be calculated as the steady-state concentration in the plasma * the clearance.

[edit] Sample values and equations

Variable	Abbreviation(s)	Example value	Formula
Dose (loading dose, or steady state/maintenance)	D (LD or MD)	1000 mg	=V_d*C₀
Volume of distribution	V_d	25 L	=D/C₀
Concentration (initial or steady-state)	C₀ or C_ss	40.0 mg/L	=D/V_d
Biological half-life	T_½	14 hr	=0.7/K_e
Elimination rate constant	K_e	0.05/hr	=0.7/(T_½) =Cl/V_d
Elimination rate, or rate of infusion to balance elimination	K_in	50 mg/hr	=C_ss*Cl
Clearance	Cl	1.25 L/hr	=V_d*K_e
Bioavailability	F	1	$= \frac{[AUC]_{A}dose_{B}}{[AUC]_{B}dose_{A}}$

Note that the "0.7" constant is a commonly used log approximation, but not the actual value. Another commonly used approximation is 0.693 for -ln(0.5) = 0.69315...

[edit] References

This pharmacology-related article is a stub. You can help Wikipedia by expanding it.

[urlCp_vs_time_-_iv_infusion-0] "Cp vs time - iv infusion". http://www.chm.davidson.edu/erstevens/iv%20inf%20Cp%20v%20t/iv%20inf%20Cp%20v%20t.html.

[urlChapter_15.2_-_Continuous_IV_Infusion_-_Steady_State-1] "Chapter 15.2 - Continuous IV Infusion - Steady State". http://www.boomer.org/c/p3/c15/c1502.html.

[1]

[2]