No abstract available.

No abstract available.

The third equation on page 44 should be corrected.

The equations on page 162 should be corrected.

In the published version of this article, the contents of Table 1 (‘Demographic characteristics of subjects’) are incorrect.

To address the debate on the safety of generic substitution quantitatively, the author compared the change in AUC in virtual patients who were simulated for several different scenarios of generic substitution. In four scenarios of original (branded) to generic and generic to generic substitution, 5,000 virtual patients were simulated per scenario using the programming software R. The mean population AUC of generics ranged from 90-110% (scenarios A and B) and 80-123.5% (scenarios C and D) of the AUC of the original. Those patients who had an AUC change (ratio) as a result of drug substitution of less than 0.67 or greater than 1.5 were considered to be in potential danger due to the substitution. We found that less than 6% of patients fell outside of the cutoff range of 0.67-1.5 as a result of original to generic substitution. However, in the case of generic to generic substitution, the proportion was as high as 9-12%. This alerts us to the potential danger of generic substitution, especially for drugs with narrow therapeutic indices.
*Area Under Curve ; Attitude to Health ; Computer Simulation ; Drug Prescriptions ; Drugs, Generic/*pharmacokinetics/therapeutic use ; Humans ; Patients/psychology/statistics & numerical data ; Software ; Therapeutic Equivalency

This tutorial deals with basic concepts of clearance, the most important parameter in pharmacokinetics but often challenging for students in clinical pharmacology. Its relationships with dose, concentration and elimination rate are discussed using a physical model and examples of commonly used drugs, as well as its physiological aspects pertaining to the blood flow to differing organs. Finally, application of clearance to the calculation of maintenance dose rate and half-life is used to show how it is essential in pharmacotherapy and clinical pharmacology.
Drug Therapy ; Half-Life ; Humans ; Pharmacokinetics ; Pharmacology, Clinical

This tutorial deals with basic concepts of volume of distribution, the second most important parameter in pharmacokinetics but often challenging for students in clinical pharmacology. Its relationships with dose, concentration and amount in the body are discussed using a physical model and examples of commonly used drugs, as well as its physiological aspects pertaining to the physical volume of differing organs. Finally, application of volume of distribution to the calculation of loading dose and half-life is used to show how it is essential in pharmacotherapy and clinical pharmacology.
Drug Therapy ; Half-Life ; Humans ; Pharmacokinetics ; Pharmacology, Clinical

Drug-drug interaction (DDI) is defined as a change in effect or safety of a drug by another co-administered drug. The fact that more than half of the market withdrawal cases for the past ten years was caused by potentially fatal DDI's demonstrates its clinical importance. The mechanism of DDI can be categorized into pharmacokinetic and pharmacodynamic interactions. Most of the clinically important drug interactions are caused by inhibition or induction of oxidative metabolism by cytochrome P450 (CYP) isozymes. Recent researches are also focusing on drug transporter interactions as another significant factor underlying DDI's. It is hard to prevent unexpected or rare DDI's. However, most of the cases of DDI occur from an erroneous prescription of drugs that are already known to result in deleterious interactions. To avoid such well-established DDI's, physicians are first recommended to utilize hands-on summary tables for CYP substrates before prescribing. It should also be remembered that old age, polypharmacy and damaged hepatic or renal function are risk factors of DDI as well as adverse drug reactions. Moreover, patients treated with drugs with a narrow therapeutic index (immunosuppressants, antiarrhythmics, anticoagulants, digoxin, theophylline etc) deserve a special consideration when their prescriptions are changed. In Korea, the clinical significance of DDI has been underemphasized. The fundamental prescription to this old prescription habit is to teach medical students and physicians clinical pharmacology and therapeutics, which have long been neglected in Korea.
Anticoagulants ; Cytochrome P-450 Enzyme System ; Digoxin ; Drug Interactions ; Drug-Related Side Effects and Adverse Reactions ; Humans ; Isoenzymes ; Korea ; Metabolism ; Pharmacology, Clinical ; Polypharmacy ; Prescriptions ; Product Recalls and Withdrawals ; Risk Factors ; Students, Medical ; Theophylline

No abstract available.
Chromosome Aberrations*