Chapter 9. Pharmacology for the Orthopaedic Physical Therapist

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

1. Differentiate between pharmacokinetics and pharmacodynamics.

2. Describe the process behind 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.

Physical therapists in many states are now positioned to provide care for patients prior to physician intervention. Although the dispensing of medications is out of the scope of practice for a physical therapist, questioning the patient about prescribed medication use can reveal medical conditions that the patient might not consider related to his or her present problem.1 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 health-care team.1 Drug therapy is one of the mainstays of modern treatments and physical therapists often encounter patients who are taking various medications. These medications may be administered to treat preexisting conditions that are not directly related to the condition being treated with physical therapy but can nonetheless have an impact on the patient's response to rehabilitation.2 Medications also can have an impact on clinical findings and on the success of an intervention.3 For example:

• Pain medications, muscle relaxants, and nonsteroidal anti-inflammatory drugs (NSAIDs) can mask signs and symptoms, thereby affecting examination findings and increasing the potential for injury during the performance of prescribed exercises.4 However, if the patient has a significant amount of pain, appropriate use of these medications may enhance treatment, allowing a more rapid progression than would otherwise be possible. However, as the patient improves, the need for this medication should lessen.
• Certain medications can produce changes in musculoskeletal structures. For example, prolonged use of corticosteroids may produce osteoporosis and weakening of connective tissues.5
• A patient undergoing anticoagulant therapy has a reduced clotting ability and is more susceptible to bruising or hemarthrosis. It is worth remembering that aspirin and aspirin-based products have an anticoagulant effect.

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). The Guide to Physical Therapist Practice6 identifies clinical pharmacology as an essential component of appropriate patient monitoring, modality delivery, and communication among medical professionals. It is 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. The prescription-drug-writing privileges exercised by select military therapists and ...