Week 2: Basic Principles of Pharmacology - Target Tissue Receptors Flashcards
The study of drugs
Pharmacology
This can be describe as “any substance that, when taken into a living organism, may modify one or more of its functions”
Drug
True or false: When you know how the various drugs may affect a patient and the mechanisms behind those effects, you can apply that knowledge to get an optimal response from the patient’s therapy treatment.
True
What do I need to know about pharmacology as a PT?
-Types of medications patient is taking
-How drugs affect the patient
-The mechanisms behind the drug effects
How can I control the drug’s adverse responses?
-Schedule the therapy based on drug’s peak effects
-Avoid or control any adverse responses from occurring due to direct interaction between physical
therapy and certain medications
The area of pharmacology that refers to the use of specific drugs to prevent, treat or diagnose a disease
Pharmacotherapeutics
The study of how the body absorbs, distributes, and eliminates the drug
Pharmacokinetics
The analysis of what the drug does to the body, including the mechanism by which the drug exerts its effect
Pharmacodynamics
The study of the harmful effects of chemicals
Toxicology
This deals with the preparation and dispensing of medications
Pharmacy
It deals with the genetic basis for drug responses, especially variations in drug response from person to person
Pharmacogenetics
True or False: Examining the genetic code for a given patient does not help predict which drugs might be most effective for that patient and which drugs should be avoided because of potentially harmful side effects.
False
What are three ways to name drugs?
-Chemical
-Generic
-Trade
Refer to the specific compound’s structure and are usually fairly long and cumbersome
Chemical names
This name is often derived from the chemical name
Generic name
This name is assigned to the compound by the pharmaceutical company and may or may not bear any reference to the two other names.
Trade/brand name
True or False: Practitioners never select and prescribe the wrong drug if its name or looks like a different drug.
False
This drug is typically less expensive than its brand name counterparts and helps reduce healthcare costs
Generic drug
True or False: The generic form of the drug should be as safe and effective as the original brand-name product
True
Why should the generic form of a drug undergo testing?
To establish that it has the same type and amount of the active ingredients, the same administration route, the same pharmacokinetic profile, and the same therapeutic effects as the brand-name drug
If testing is done, the two drugs are said to be ___________.
Bioequivalent
True or False: PTs should refer their patient to the prescribing clinician if the patient has
concerns about a drug’s the effects.
True
In the United States, who is responsible for monitoring the use of existing drugs and for developing/approving new ones?
FDA
What are two primary concerns of the FDA (U.S.) and Health Products and Food Branch of the Department of National Health and Welfare (Canada)?
-whether the drug is effective in treating a certain condition
-whether the drug is reasonably safe for human use
The development of a new drug involves extensive ______ and ______ studies.
-preclinical (animal)
-clinical (human)
What is the purpose of preclinical testing?
Initial laboratory tests to determine drug effects and safety
How many phases is human/clinical testing?
Three
Which phase is the drug usually tested in a relatively small number of healthy volunteers?
Phase I
Which phase is the drug tested in a relatively small sample with a specific disease or pathological condition?
Phase II
Which phase does the clinical evaluation expand to include more patients and more evaluators?
Phase III
Which phase does is postmarking surveillance?
Phase IV
This is for a relatively small population (<200 people) with rare disease
Orphan drugs
The use of a drug to treat conditions other than those that the drug was originally approved to treat
Off-label prescribing
True or False: When the FDA approves a drug, the approval is only for treating the conditions indicated in the New Drug Application
True
Why is off-labeling prescribing permitted?
The FDA cannot dictate how physicians and other qualified clinicians prescribe medications if the clinician has justification that the drug could benefit a given patient.
Who might refuse to reimburse the cost of a drug regarding off-label prescribing?
Insurance companies
What is OTC?
Over-the-counter drugs
OTC meds are used for __________ problems.
minor
This type of drug is less expensive but the actual cost might be greater because of directly pay out of pocket
OTC meds
True or False: OTC use does not cause serious interactions with a patient’s medications
False
True or False: PTs should not directly prescribe or administer OTC products
True
What can a PT do for a patient if they cannot prescribe/administer OTC products?
Provide information about the proper use and potential benefits of these medications
True or False: Many drugs that were formerly available only by prescription are now available in a nonprescription form.
True
List of substances that were controlled in 1970 when the CSA (Controlled Substances Act) was enacted, as well as the substances that have been added since that time
Drug Schedule
How many categories are in the Drug Schedule?
5
These drugs are regarded as having the highest potential for abuse and are not typically sued as an acceptable medical treatment in the U.S.
Schedule I
These drugs have the lowest relative abuse potential. Drugs in this category consist primarily of low doses of opioids that are used in cough medications and antidiarrheal preparations.
Schedule V
Drugs in this category are approved for specific therapeutic purposes but still have a high potential for abuse and possible addiction.
Schedule II
Drugs in this category may cause a person to still develop mild to moderate physical and/or strong psychological dependence.
Schedule III
These drugs may cause a person to have a limited possibility of physical and/or psychologic dependence.
Schedule IV
Why does a drug change the function of a cell?
-To help restore normal physiological function
-Prevent a disease process from occurring
This provides information about the dosage range over which the drug is effective, as well as the peak response that can be expected from the drug.
Dose-response curve
Very _____ doses do not produce any observable effect.
low
At ___________ dose, the response begins to occur and continues to increase in magnitude before reaching a plateau.
threshold
The ________ indicates that there will be no further increment in the response, even if the dosage continues to be increased.
plateau
The point at which there is no further increase in the response.
Ceiling/maximal effect
This term is related to the dose that produces a given response in a specific amplitude
Potency
When two drugs are compared, the more potent drug requires a _______ dose to produce the same effect as a ________ dose of the second drug.
-lower
-higher
A dose of 10 mg of drug A would lower blood pressure by 25%, whereas 80 mg of drug B would be required to produce the same response. Which drug is more potent?
Drug A
True or False: Potency and maximal efficacy fully indicate a drug’s therapeutic potential.
False
This curve shows the percentage of the population that exhibits a specific response as the dosage is increased.
Quantal Dose-Response Curve
This is the dose at which 50 percent of the population responds to the drug in a specified manner (ex: absence of headache)
Median effective dose (ED 50)
True or False: Higher doses of the same medication is not is not associated with the appearance of a specific toxic effect.
False
This is the dose at which 50 percent of the group exhibits the adverse effect.
Median toxic dose (TD 50)
Two doses that are used to determine the therapeutic index (TI)
Median effective and toxic doses
This indicates a drug’s safety
Therapeutic Index (TI)
The greater the value of the TI, the __________ the drug is considered to be
safer
A large TI indicates that it takes a ________ dose to evoke a toxic response than it does to cause a beneficial effect
larger
What are the routes of drug administration?
-Alimentary canal (enteral administration)
-Non alimentary canal (parenteral administration)
The most common method of enteral medication administration, especially when self-administration is necessary or desired.
Oral
Most medications that are administered orally are absorbed from the ___________.
Small intestine
True or false: Drugs that are administered by mouth must have a relatively high degree of lipid solubility in order to pass through the GI mucosa and into the bloodstream.
True
___________ are absorbed very poorly from the alimentary canal and will be eventually lost through the feces.
Large, nonlipid-soluble
This structure enhances entry in the body for oral administration
Intestinal microvilli with a large surface area
Where is the drug transported after absorption from the alimentary canal?
Liver via portal vein
This occurs when a significant amount of the drug may be metabolized and destroyed prior to reaching its site of action
First-pass effect
True or False: The amount and rate at which the drug eventually reaches the bloodstream is predictable for the oral route.
False
Drugs administered by placing the drug under the tongue
Sublingual
Drugs administered by placing the drug between the cheek and gums
Buccal
True or False: Sublingual and buccal drugs can reach the systemic circulation without being subjected to first-pass inactivation in the liver.
True
True or False: Sublingual and buccal drugs have slower effects compared to swallowing the drug.
False
This method is less favorable because many drugs are absorbed poorly or incompletely
Rectal
When is the rectal method useful?
-unconscious patient
-vomiting prevents drugs from being taken orally
This method treats local conditions such as hemorrhoids
Rectal
True or false: Parenteral methods are aimed more directly to the site
True
Examples of parenteral administration include:
Inhalation, injection, topical, and transdermal
Method for rapid entry into the bloodstream through diffusion into the pulmonary circulation
Inhalation
True or false: Inhalation has a limited ability to predict exactly how much the drug eventually reaches the lungs
True
Why is pulmonary administration adventageous?
Large (alveolar) surface area for diffusion
True or False: Drug particles are never trapped by cilia and mucus in the respiratory tract
False
Various types of injection can be used to introduce the drug either _________ or __________.
-systemically
-locally
True or false: The bolus injection of a medication into a peripheral vein allows an accurate, known quantity of the drug to be introduced into the blood stream over a short period of time.
True
This method is advantageous in emergency situations when it is necessary for medication to an immediate effect
IV
This can be used to allow the prolonged, steady infusion of a drug into the venous system
IV cannula (IV “line)
True or False: Intra-arterial injections are a relative difficult and dangerous procedure
True
This method is occasionally used in chemotherapy to minimize the exposure of the drug to healthy tissue
Intra-arterial Injection
This method has a relatively slower, more prolonged release into the system circulation (ex: local anesthesia, insulin, hormonal contraceptive products)
Subcutaneous (SC) Injection
The large quantity of skeletal muscle in the body allows this route to be easily accessible.
Intramuscular (IM) Injection
IM injections are useful for treating a problem located directly in the _____________.
Injected muscle
What is the benefit of IM injections?
They provide a relatively rapid effect while avoiding the sudden, large increase in plasma levels seen with IV injection
This method delivers the medication within a sheath (ex: spinal subarachnoid space, local anesthetics, etc.)
Intrathecal injection
True or false: Intrathecal injections do not allow certain drugs to bypass the blood-brain barrier and reach the CNS
False
Intrathecal injections may include administration of the drug for these sites to treat inflammation
Tendon sheath or bursa
Drugs given topically are applied to the surface of the _____________.
Skin/mucous membrane
Why do topical medications primarily help treat problems that exist on the skin itself?
Most medications applied directly to the skin are abosorbed fairly poorly through the epidermis and into the system circulation
What can topical drugs be used to treat?
-infections
-inflammation
-wound healing
True or false: Topical application of drugs to mucous membranes can therefore provide a fairly easy and convenient way to administer drugs systemically
True
Drugs for this method are absorbed through the dermal layers and into the subcutaneous tissues or the peripheral circulation
Transdermal
A transdermally administered drug must possess two basic properties. What are these properties?
-must be able to penetrate the skin
-must not be degraded to any major extent by drug metabolizing enzymes located in the dermis
Transdermal administration provides a ______, _______ release of the drug into the body
slow, controlled
Drugs administered transdermally are often delivered through _______ adhered to the skin.
medicated patches
True or false: The transdermal method allows the prolonged administration of drugs
True
What are iontophoresis and phonophoresis used for?
Treating pain and inflammation
Electric current “drives” the ionized form of the medication through the skin
Iontophoresis
Uses ultrasound waves to enhance transmission of the medication through the dermis
Phonophoresis
The extent to which the drug reaches the system circulation
Bioavailability
If 100 mg of a drug is given orally and 50 mg eventually make it into the systemic circulation, the drug is said to be _______% bioavailable.
50%
What is bioavailability dependent on?
The route of administration and drug’s ability to cross membrane barriers
Lipid-soluble compounds are able to pass directly through the membrane by dissolving in the _________.
Lipid bilayer
This structure is composed of primarily lipids and protein
Cell membrane
True or false: Many drugs do not affect dynamic ion channels’ abilities to open and close, altering cell excitability
False
Types of movements across membrane barriers
-passive diffusion
-active transport
-facilitated diffusion
-endocytosis
This occurs when the concentration of the substance differs on one side of the membrane compared to that on the other side
Concentration gradient
The driving forces in passive diffusion
Electrical, chemical, and pressure differences
What does the rate of passive diffusion depend on?
-magnitude of the gradient
-size of the substance
-distance
-temperature
The membrane must be _________________ to the diffusing substance
Permeable
Many drugs are ___________ soluble
Lipid
