| A, B, C | Preexponential constants for three-compartment model equation |
| α | Probability of making a type 1 error |
| β | Probability of making a type 2 error |
| α, β, γ | Exponents for three-compartment model equation |
| λ1, λ2, λ3, …λz | Exponents for three-compartment-type exponential equation (more terms may be added and indexed numerically with subscripts for multiexponential models), and exponent describing the last terminal phase (λz) regardless of the total number of exponents needed. |
| Delta (Δ) | Delta is sometimes referred to as the “effect size” and is a measure of the degree of difference between tested population samples |
| μ0 | The null hypothesis value for the mean |
| μa | μa is the alternative hypothesis value expected for the mean |
| χ2 | Chi-square test |
| Ab∞ | Total amount of drug in the body |
| ABC | ATP-binding cassette |
| ABCB1 | Gene coding for p-Glycoprotein; see also MDR1 |
| ABW | Actual body weight |
| ADME | Absorption, distribution, metabolism, and excretion |
| AE | Adverse event |
| Aeij | Amount of drug excreted from time i to time j (usually in urine or feces) |
| Ae(m)ij | Amount of metabolite excreted from time i to time j (usually in urine or feces) |
| ANCOVA | Analyses of covariance |
| ANOVA | Analysis of variance |
| API | Active pharmaceutical ingredient |
| AR | Absolute risk |
| ARI | Absolute risk increase |
| AUC | Area under the concentration–time curve |
AUCinf, AUC0-inf,  | Area under the concentration–time curve extrapolated to infinite time |
| AUC0-t, | Area under the concentration–time curve from time 0 to the last measurable drug concentration at time t |
| AUCtau, AUCτ | Area under the concentration–time curve over the dosing interval |
| AUCtau(ss), AUCτ(ss) | Area under the concentration–time curve at steady state |
| AUMC | Area under the (first) moment–time curve |
| BA | Bioavailability |
| BCS | Biopharmaceutics Classification System |
| BDDCS | Biopharmaceutics Drug Disposition Classification System |
| BE | Bioequivalence, Bioequivalent |
| BM | Biomarker |
| BMI | Body mass index |
| BRCP | Breast cancer–resistance protein |
| BUN | Blood urea nitrogen |
| C | Concentration (mass/volume) |
| Ca | Drug concentration in arterial plasma |
| Cav(ss), | Average steady-state plasma drug concentration |
| Cp | Concentration of drug in plasma |
| Screat | Serum creatinine concentration, in American units expressed as mg/dL |
| CE | Clinical endpoint |
| Ceff | Effective drug concentration |
| CGI | Concentration of drug in gastrointestinal tract |
| CI | Confidence interval |
| Cm | Concentration of metabolite |
| Cmax | Maximum concentration |
| Cmax(SS), | Maximum concentration of drug at steady state |
| Cmin | Minimum concentration of drug |
| Cmin(SS) | Minimum concentration of drug at steady state |
| Concentration of drug in plasma at zero time (t = 0) (equivalent to C0) |
| Css, | Steady-state plasma drug concentration |
| Ct | Concentration of drug in tissue |
| CFR | Code of Federal Regulations |
| cGMP | Current Good Manufacturing Practices |
| CKD | Chronic kidney disease |
| CL, CLT | Total body clearance |
| CLCR | Creatinine clearance |
| CLD | Distributional clearance |
| CLDIAL | Dialysis clearance |
| CDD | Critical dose drug |
| CLH | Hepatic clearance |
| CL... |