Pharm I

Pharmacology

Body of knowledge studying action of chemicals on biologic systems

Medical Pharmacology

Pharmacology studying the use of chemicals in prevention, diagnosis, and treatment of dieases.

Pharmacology Goals

Place patient in chemically induced coma to facilitate surgical intervention, maintain homeostasis, and reverse effects to pre-anesthetic state without harm.

Pharmacodynamics

Study of intrinsic receptor sensitivity or responsiveness of a drug and its effect mechanisms. The effect a drug has on the body.

What explains why patients may respond differently to the same drug?

Pharmacodynamics

What 3 concepts are associated with pharmacodynamics?

Potency, efficacy, and therapeutic window.

Hyperreactive

Unusually low dose produces expected effect. Lightweight.

Hyporeactive

Exceptionally high dose needed to produce the expected effect. Second propofol vial.

Hypersensitive

Allergic response to a drug. Cross sensitivity with similar drugs.

Tolerance

Acquired hyporeactivity from chronic exposure. Chronic opioid use.

Cross-tolerance

Tolerance to one drug transfer to another with similar mechanism. Opioids or benzos

Tachyphylaxis

Acute tolerance after a few doses. Neosynephrine increase law.

Densensitization

Short term lower receptor responsiveness after repeated stimulation.

Example of desensitization

B2 Agonists

Downregulation

Longterm lower receptor number due to prolonged exposure

Downregulation examples

B2 agonists, opioids, benzos

Idiosyncrasy

Unpredictable, unusual reaction, regardless of dose. Propofol shakes.

Additive Effect

Combined effect= Individual effects SUM

Additive Effect Example

Volatile anesthetic + N2O MAC

Synergistic Effect

Combined effect > Individual effects SUM

Synergistic Effect Example

Benzos+Opioids = respiratory depression