Pharmacology For The Physical Therapy Clinician
Pharmacology can be broadly defined as the science dealing with interactions between living systems and molecules
Throughout the ages, drugs have been produced using natural plant and animal products by native people. This practice has been part of every culture and society in every corner of the world.
Some Examples…….
PPT Slide
Echinacea - the roots, seed heads & petals can be used to make an Echinacea tincture and salve
Jojoba - the beans and the leaves are used to make a variety of oil, soap & shampoo products.
Advantages Of Synthetic Drugs
Greater drug concentration
Drug Interactions With A Biological System
Pharmacodyamic Interactions
Pharmacokinetic Interactions
Drug Nomenclature
Examples…….
Phenobarbitol
Generic Name
Dantrolene Sodium
Trade Name
Digoxin is the generic name for the drug with the trade name of :
Bepridil HCl is the generic name for a drug with the trade name of :
The FDA catalogs the drug by its generic name
Routes of Administration
Enteral Routes
Advantages Of The Enteral Route
The enteral route avoids large fluctuations in drug delivery
Disadvantages of the Enteral Route
First Pass Effect
Parenteral Routes
Advantages of Parenteral Routes
Ease of self administration (topical, inhalation, rectal, & subcutaneous routes)
During First Pass Effect, a certain percentage of the drug is changed from the original mother compound into some intermediate metabolite. All of the drug then passes out into the systemic circulation as 1) the intact drug plus its 2) changed intermediates.
For some drugs, like sublingual nitroglycerin, if it were swallowed, it would be totally inactivated by the liver. So, its first pass effect is complete or 100%
For other drugs that are not as easily cleaved, the First Pass Effect might only be 10%. This means that 90% of the mother compound enters the systemic circulation with only 10% that has been changed into an intermediate.
The intermediate compounds after First Pass Effect may be biologically inactive or they might be extremely active in the body. Many cancer drugs are designed to have intermediates that are just as biologically active against the tumor as the mother compound.
Some medications are designed to be inactive in the pill form. Once these medications pass into the liver (First Pass Effect) they are cleaved into their biologically active intermediate forms. In the pill form, these drugs are called Pre-Drugs.
Bioavailability
Factors Influencing Bioavailability
Blood flow at the intended target organ or site
Drug Elimination
Biotransformation
Enzyme Induction
There are many stimuli that cause enzyme induction to be turned on such as :
Why Do Humans Respond Differently To Medications ?
Email: David.Arnall@NAU.EDU , DAArnall@AOL.COM
Home Page: http://jan.ucc.nau.edu/~daa/pt675/
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