Anathawa/PKmisc

Miscellaneous equations tools for clinical pharmacokinetics

PKmisc

Miscellaneous equations and tools for clinical pharmacokinetics

Miscellaneous functions

• nca(): Non-compartmental PK analysis, e.g. AUC, half-life, etc.
• calc_kel_single_tdm(): calculate elimination rate (for linear 1-cmt model) based on single TDM sample and provided volume of distribution.
• calc_t12(): calculate effective half-life based on two TDM points.
• calc_amts_for_conc(): Calculate the amounts in all compartments in a compartmental PK system based on a given concentration in the central compartment, and assuming steady state.
• find_nearest_dose(): Find nearest available dose based on smallest available dosing unit
• find_nearest_interval(): Find nearest (or nearest higher / nearest lower) dosing interval

Anthropomorphic equations

• calc_bsa(): BSA calculation using various equations
• calc_ffm(): Fat-free mass using various equations
• calc_bmi(): Body mass index
• calc_ibw(): Ideal body weight, using various equations for children and adults
• calc_lbw(): Lean body weight
• calc_abw(): Adjusted body weight (for obese patients)
• pct_weight_for_age(): calculate percentile of weight given age (for kids <= 10 yrs)
• pct_height_for_age(): calculate percentile of height given age (for kids <= 19 yrs)
• pct_bmi_for_age(): calculate percentile of height given age (for kids <= 19 yrs)

Clinical chemistry

• calc_egfr(): eGFR calculation from serum creatinine using various equations (Cockroft-Gault, MDRD, CKD-EPI, Jelliffe, Jelliffe for unstable patients, Wright, Lund-Malmo revised, Schwartz, Schwartz revised)
• calc_egfr_cystatin(): eGFR calculation from Cystatin C concentrations using various equations (Grubb, Larsson)
• calc_creat(): mean serum creatinine for children and adults (given age and sex)
• calc_creat_neo(): typical serum creatinine for neonates given post-natal age
• convert_creat_assay(): convert between various creatinine assays (Jaffe, IDMS, etc)
• convert_creat_unit(): convert between creatinine units (mmol/L, mg/dL)

Conversions

• kg2lbs(): kg to pounds
• lbs2kg(): pounds to kg
• weight2kg(): any weight unit to kg
• cm2inch(): cm to inches
• inch2cm(): inches to cm
• conc2mol(): concentration to molar
• mol2conc(): molar to concentration

PK compartmental equations

Functions to simulate concentrations for linear PK models.

function	compartments	administration	type	output
pk_1cmt_inf()	1	infusion	single/multi dose	concentration table
pk_1cmt_inf_ss()	1	infusion	steady state	concentration table
pk_1cmt_inf_cmin_ss()	1	infusion	steady state	Cmin
pk_1cmt_inf_cmax_ss()	1	infusion	steady state	Cmax
pk_2cmt_inf()	2	infusion	single/multi dose	concentration table
pk_2cmt_inf_ss()	2	infusion	steady state	concentration table
pk_2cmt_inf_cmin_ss()	2	infusion	steady state	Cmin
pk_2cmt_inf_cmax_ss()	2	infusion	steady state	Cmax
pk_1cmt_bolus()	1	bolus	single/multi dose	concentration table
pk_1cmt_bolus_ss()	1	bolus	steady state	concentration table
pk_1cmt_bolus_cmin_ss()	1	bolus	steady state	Cmin
pk_1cmt_bolus_cmax_ss()	1	bolus	steady state	Cmax
pk_1cmt_t12()	1	-	-	half-life
pk_2cmt_bolus()	2	bolus	single/multi dose	concentration table
pk_2cmt_bolus_ss()	2	bolus	steady state	concentration table
pk_2cmt_bolus_cmin_ss()	2	bolus	steady state	Cmin
pk_2cmt_bolus_cmax_ss()	2	bolus	steady state	Cmax
pk_2cmt_t12()	2	-	-	terminal half-life
pk_2cmt_t12_interval()	2	-	-	effective half-life in given interval

Dose / TDM calculations

Functions to calculate the dose expected to achieve a specific target exposure.

function	compartments	administration	target	output
pk_1cmt_inf_dose_for_cmin	1	infusion	cmin	dose
pk_1cmt_bolus_dose_for_cmin	1	bolus	cmin	dose
pk_2cmt_inf_dose_for_cmin()	2	infusion	cmin	dose
pk_2cmt_bolus_dose_for_cmin()	2	bolus	cmin	dose
pk_1cmt_inf_dose_for_cmax	1	infusion	cmax	dose
pk_1cmt_bolus_dose_for_cmax	1	bolus	cmax	dose
pk_2cmt_inf_dose_for_cmax()	2	infusion	cmax	dose
pk_2cmt_bolus_dose_for_cmax()	2	bolus	cmax	dose
dose2auc()	1	-	auc	auc
auc2dose()	1	-	auc	dose