Introduction
Pharmacology denotes the scientific study of drugs and their interactions with the body with respect to their preparation, properties, use, and impact. The two main segments of pharmacology are pharmacokinetics (PK) and pharmacodynamics (PD). The comprehension of the exposure-reaction relationship (PK and PD) is essential for the development and endorsement of any drug (Wind, Schnell, Ebner, Freiwald, & Stopfer, 2017). PK and PD information contribute most of the details on a drug package. PD represents the interaction between the concentration of a drug and the desired response or undesirable adverse effects that follow. Premeditated planning and evaluation of the entire operation of a drug in terms of its PK and PD can hasten the development progression.
Differences
PK denotes the movement of drugs throughout the body while PD concerns the body’s biological reaction to such medicines. PK delineates the exposure of a drug by depicting its absorption, spread, bioavailability, breakdown, and excretion over time. However, PD entails the body’s response to the drug with respect to molecular and biochemical interactions. For example, medical PK is the application of principles to the safe and efficacious clinical management in a patient. Primary objectives of clinical PK encompass the improvement of efficacy and reduction of the toxicity of the drug therapy of a patient. Development of powerful correlations involving medication concentrations and their pharmacologic reactions has empowered drug manufacturers to employ PK principles to real patient conditions. The effect of a drug is associated with its concentration at the intended site, which makes it helpful to monitor the concentration (Wind et al., 2017). Since receptor sites of medicines are inaccessible to easy observation or are broadly distributed within the body, direct quantification is impractical. A good example of PK is the receptor positions for digoxin which are found in the myocardium. Although it is not possible to directly measure drug concentration in the tissue, this may be done in either blood, plasma, saliva, or urine hence signifying the movement of drugs in the body.
The connection involving the dosage administered and the ensuing concentration at the position of action results in pharmacodynamic response. This signifies that medicines apply clinical effects by either imitating or obstructing normal biochemical courses. The effectiveness of a drug is associated with a positive receptor, protein target, or ion channel relationship. An example of PD is in morphine binding receptors on neurons to reduce pain (Juul et al., 2016). Another example of PD entails serotonin reuptake inhibitors attaching on nervous system receptors or gastrointestinal tract and making them helpful for a range of diagnoses. Inconsistency may arise in receptors with which medications network. Drug concentration within the body might be in line with the desired scope for effectiveness but genetic inconsistency in receptor cells may restrict the interaction. The wanted response might fail to occur even with what would characteristically be a sufficient drug concentration. The interaction between PK and PD is fundamental in the assessment of the therapeutic efficacy, side effects, or toxicity.
Conclusion
Pharmacology signifies the scientific study of drugs and their impact in the body regarding development, properties, use, and impact. The major segments of pharmacology include PK and PD. Calculated planning and appraisal of the entire operation of a drug concerning its PK and PD can hasten and improve the development progression. While PK represents the movement of drugs throughout the body, PD concerns the body’s biological response to such medications.
References
Juul, R. V., Nyberg, J., Lund, T. M., Rasmussen, S., Kreilgaard, M., Christrup, L. L., & Simonsson, U. S. (2016). A pharmacokinetic-pharmacodynamic model of morphine exposure and subsequent morphine consumption in postoperative pain. Pharmaceutical Research, 33(5), 1093-1103.
Wind, S., Schnell, D., Ebner, T., Freiwald, M., & Stopfer, P. (2017). Clinical pharmacokinetics and pharmacodynamics of afatinib. Clinical Pharmacokinetics, 56(3), 235-250.