CHAPTER 9: Pharmacology for the Orthopaedic Physical Therapist

CHAPTER OBJECTIVES

At the completion of this chapter, the reader will be able to:

1. Differentiate between pharmacokinetics and pharmacodynamics.

2. Describe the process of drug development, regulation, and distribution.

3. Describe controlled substances and their potential for abuse.

4. Recognize the three different names used for drugs.

5. Describe the various modes of action of drugs.

6. Describe the various drug receptor sites within the body.

7. Outline the different administration routes used for drug delivery.

8. Understand the potential effects of physical agents and exercise on drug delivery.

OVERVIEW

Pharmacology is the broad area of study that deals with how chemical substances affect living tissue on a molecular level and how drugs affect specific patient populations (Table 9-1). Drug therapy is one of the mainstays of modern treatments, and physical therapists often encounter patients who are taking various medications. The Guide to Physical Therapist Practice¹ identifies clinical pharmacology as an essential component of appropriate patient monitoring, modality delivery, and communication among medical professionals. It is therefore important for the physical therapist to have a working knowledge of pharmacology because of the number of drugs currently on the market and the number of physical therapy patients that are likely to have been prescribed medications. As physical therapists attempt to account for the effects of their interventions, it becomes apparent that they must also understand the effect and potential interactions of all available and reasonable resources, including pharmacological interventions, offered by other members of the healthcare team.² The prescription-drug-writing privileges exercised by select military therapists and the evolution of the physical therapy profession promote consideration of an expanded pharmacological role in physical therapy practice.³ Although the dispensing of medications is currently out of the scope of practice for the vast majority of physical therapists, questioning the patient about prescribed medication use can reveal medical conditions that the patient might not consider related to his or her present problem, as the prescribed medications may be for pre-existing conditions that are not directly related to the condition being treated with physical therapy. In addition, this information can also provide the clinician with possible reactions that the patient may have to exercise or other treatment procedures, and the impact on clinical findings. For example: