Which statement is the best description of a drug's serum half-life?
C. the time required after absorption for half of the drug to be eliminated
Which (actors most commonly affect a drug's action?
D. poor circulation, pain, stress, hunger, fasting
Older Pt rules-of-thumb
Tired organs
Accumulate drugs dur to age
Use smallest effective dose
Use shortest effective time
e.g. Start low, go slow
Try non-drug measures first
Keep in mind their vision and tactile abilities
Pts on herbal therapies vis-a-vis surgery
Stop all herbal therapies 2-3 weeks before surgery.
Saint John's Wart
Less depression
Similar to Prozac (increases serotonin in the brain)
Inhibits metabolism of many drugs
ginseng
Extra energy and increased mental alertness
May depress or stimulate the CNS.
May cause hypertension, palpitations.
May increase the risk of bleeding.
Decreases blood glucose and cholesterol (again is this too much?).
garlic
Decreases BP, BS & lipids
May increase the risk of bleeding.
May decrease glucose and cholesterol (too much?)
Echinacia
Good for the common cold.
Stimulates the immune system, may aggravate autoimmune disorders.
Hepatoxic.
Chamomile
It has a calming effect...
May increase the risk of bleeding.
Name 3 drug forms that cannot be crushed and why?
Enteric: designed to be absorbed in SI not stomach
Anything ER, SR, XR or XL: Results in a faster release of drug for distrubution that designed
Capsules: Same reason as above.
Meds in ears...
Nose - (head back, maintain 2 -3 minutes)
Admin of meds to eye...
0: Wash hands, don gloves
1: Into conjunctival sac
2: Press lacrimal duct for 1-2 min to prevent systemic absorption.
3: Pt eyes closed for 1-2 min to promote absorption
Antidote for Coumadin
Vitamin K
Antidote for Opioids
Narcan
Antidote for Heparin
Protamine sulfate (1 mg per 100 units of heparin that had been given over the past four hours) has been given to counteract the anticoagulant effect of heparin.
Antidote for Digoxin
Digibind - the specific antidote is antidigoxin (antibody fragments against digoxin, trade names of Digibind and Digifab).
Antidote for Tylenol
Mucomyst also known as N-acetylcysteine or N-acetyl-L-cysteine (abbreviated NAC).
The antidote to acetaminophen overdose, N-acetylcysteine (NAC), is most effective when taken within eight-hours of an overdose.
Antidote for Tricyclic Antidipressants
Sodium Bicarbonate
Tachyphylaxis?
Tolerance after only a few doses
Tolerance as an adverse effect
Larger doses needed.
Administation of Steroids
Must be taken with foods
Adverse effects: Carcinogenicity
Many anticancer drugs, e.g. Cyclopamine, are paradoxically carcinogenic in healthy individuals
Adverse effects: Teratogenicity
Harmful to the developing fetus
Adverse effects: Dependence
Any of the C-II through C-IV drugs,
Adverse effects: Idiosyncrasy
Unbexpected with 1st time dose.
Adverse effects: Hypersensitivity
Adverse effects: Nephrotoxicity
Motrin
Adverse effects: Hepatoxicity
Tylenol (acetominophen)
Thorazine
MAO inhibitors
Dilantin
aspirin
Adverse effects: Hematologic
Phenytoin sodium is a commonly used antiepileptic.
Has been suggested that phenytoin causes a reduction in folic acid levels, predisposing patients to megaloblastic anemia.
Adverse effects: Gastrointestinal
Nausea
vomiting
diarrhea
bleeding
Adverse effects: CNS
Stimulation or depression
AAAA are more severe than side effects and are always BBBB. They may be mild or severe.
A: Adverse reactions
B: Undesirable.
Ethnopharmacology?
The study of drug responses that may be unique to an individual due to social, cultural and biologic phenomena.
Categories & characteristics of Photosensitivity
Photoallergy & Phototoxicity
Photoallergy is immune-based and is only related to previous exposure.
Phototoxicity may be dose-based and resaults in damage (serious sun burn) to skin where exposed.
1: SPF 15 or greater and
2: Avoid sunlight and
3: Wear protective clothing
Drug-drug interaction: Antagonism
Each drug's actions nullify the other drugs actions with a net 0 result.
Narcan nullifys the actions of drugs.
Drug-drug interaction: Displacement
If the binding sites of one drug are "used up" by a 2 drug, this increases the effects of the displaced drug as the displaced drug is circulating in unbound orfree form
e.g. aspirin * Coumadin = increased anticoagulant effect
Drug-drug interaction: Interference
Intensified effects of 2nd drug due to lst drug interfering with its metabolism and excretion
e.g. Tagament interferes with many drugs
Drug-drug interaction: Synergism
Because they have different sites of action: Tylenol + Codeine = increased pain relief
Per the book, their "clinical effect is substantially better than the combined effect of the two."
Drug-drug interaction: Additive
Can be desirable or not.
Sedative + alcohol = increased sedation.
Beta blocker + diuretic = better treatment of hypertension.
Digitalis contraindications?
With digoxin and
Decreased serum potassium and
Decreased serum magnesium or
Increased serum calcium level,
Digitalis toxicity may result.
Drugs from the thiazide diuretic group can cause abnormal electrolyte concentrations.
An example is hydrochlorothiazide (HydroDIURIL), which can
Decrease serum potassium, magnesium, and sodium levels and
Increase the serum calcium level.
Hydrochloro-thiazide promotes potassium loss, and low serum potassium results in an increase in the uptake of digoxin by myocardial tissue.
This sensitization of the myocardium to digoxin increases the risk of digitalis-induced arrhythmias.
When digoxin and hydrochlorothiazide are taken together, the nurse should observe the client for digitalis toxicity.
Symptoms are nausea, vomiting, bradycardia, and stated visual problems, e.g. "yellow vision".
Clients on long-term therapy should have regular digoxin levels drawn to detect earlytoxicity.
Pro & Con Food considerations?
Pro - with food: beta blocker metoprolol (Lopressor)
Con - without food: Levothyroxine
Tetracycline contraindication?
Dairy products can interfere with the antibiotic effects of tetracycline.
Coumadin contraindication?
Vitamin K found in green leafy vegetables will inactivate the blood thinning effects of Coumadin.
MAOI contraindication?
If monoamine metabolism is compromised by the use of monoamine oxidase inhibitors (MAOIs) and
Foods high in tyramine are ingested, then
A hypertensive crisis can result,
As tyramine can cause the release of stored monoamines, such as dopamine, norepinephrine and epinephrine.
Foods that are high in tyramine?
Beer
Wine
Cheese
Yeast products
Chicken livers
Pickled herring
Discuss the following nonreceptor drug actions: Antacids
Neutralize hydrochloric acid
Discuss the following nonreceptor drug action: Osmotic diuretics
Increase osmolarity of the plasma and pull water out of the tissues into the blood, e.g. Manitol for head injuries
Discuss the following nonreceptor drug action: Nucleic acids
Similar to nutrients / incorporated into body
Discuss the following nonreceptor drug action: Metal chelating agents
Combine with toxic metals for excretion
List 5 characteristics of receptors.
Different types - mainly proteins
Number of sites available affects extent of drug action
Drugs chemical structure affects ability of the drug to reach tissues
Drug reaction with receptors causes agonism or antagonism
Receptors may increase or decrease in their sensitivity
What happens when drug molecules bind with receptors?
Stimulation or inhibition of cell function
Changes in cell permeability
Involvement of neurohormones (i.e. acetylcholine, norepinephrine, serotonin)
What is the "ligand-binding domain"?
It is the site on the receptor at which drugs bind.
Where are receptors located?
Kinase-linked receptors: The ligand-binding domain for drug binding is on the cell surface.
Ligand-gated ion channels: The channel spans the cell membrane and, with this type of receptor, the channel opens, allowing for the flow of ions into and out of the cells.
G protein-coupled receptor systems: There are three components to this receptor response: (1) the receptor, (2) the G protein that binds with guanosine triphosphate (GTP),and (3) the effector that is either an enzyme or an ion channel.
Nuclear receptors: Found in the cell nucleus (not on the surface) of the cell membrane.
Types of drug receptors?
1: Kinase-linked receptors
2: Ligand-gated ion channels
3: G protein-coupled receptor systems
4: Nuclear receptors.
MTC
Minimum Toxic Concentration
Rules-of-thumb for drug half-lives:
4 to 5 half-lives of administration to...
Reach steady state or to...
Drop below MEC
At "steady state" the intake = metabolized & excreted.
Toxcity?
The first adverse symptoms that occur at a particular dose.
Affects on metabolism and toxicity are interrelated.
Toxicity is more prevalent in persons with liver or renal impairment or in the very young or old Pt.
MEC
Minimum Effective Concentration, i.e. just at the therapeutic level.
Serum Drug level?
Amount of drug in the blood at a particular time.
What can happen if drug excretion is impaired?
Renal dysfunction either in older adults or as a result of kidney disorders, drug dosage usually needs to be decreased.
When creatinine clearance is decreased, drug dosage likewise may need to be decreased.
Continuous drug dosing according to a prescribed dosing regimen without evaluating creatinine clearance could result in drug toxicity.
Normal creatinine clearance is 85 to 135 mL/min.
Older adult clients may have a creatinine clearance of 60 mL/min.
What is enterohepatic recirculation?
1: Excreted in the bile
2: Reabsorbed by the SI
3: Returned to the liver
4: Excreted by the kidney
When are drugs not eliminated by the kidneys?
When they are bound to proteins
How are drugs excreted?
Drug elimination is most often via the kidney, although elimination may also take place via the [7 factors?]
1: liver
2: bile
3: feces
4: lungs
5: saliva
6: sweat
7: breast milk
What conditions cause an increase in metabolism?
Steroids
High protein diets
Enzyme inducers
Anticonvulsant drugs
Cigarette smoke
Tagamet (antiulcer) is an enzyme inhibitor, so it would NOT "INC Metabolism"!
Enzyme inhibition - defined
Increases drug action by reducing availability of enzymes for metabolism. (more often the case)
In this case, smaller doses of the drug are needed because of slower drug metabolism.
Enzyme induction - defined
Most often decreases drug action, that is increased activated (induced) enzymes will more rapidly metabolize drugs into non-active forms for secretion.
However, enzyme may be responsible for metabolizing a pro-drug into a drug, which can increase drug action
What is metabolism of a drug?
Most often metabolism refers liver enzymes changing a lipid soluable drug into a water-sol for excretion by kidneys.
Some times though the liver can change a drug into something more potent than the drug itself.
The old (decreased liver func) and the young (imature liver func) are more suseptible to drugs.
What kind of drugs are able to act on body cells?
Only those that are free, that is not bound to any proteins
Discuss where drugs are distributed quickly or slowly.
It all depends on vasculature. So, fat - slow; muscle - fast, at least for injections.
The term distribution refers to the drug becoming available to body fluids and body tissues. Distribution is influenced by [4 factors?].
blood flow
affinity to the tissue
drug dosage
drug concentration in the body
Drug absorption can be altered by [8 factors?].
blood flow
pain
stress
hunger
fasting
food
pH
method of administration
Fastest drug absorption?
mucous membranes - faster than IV per Maddie
How are lungs involved in drug interactions?
Lungs can quickly take in drugs to the blood supply because of its great area 70 m2 (25' x 35') and lungs are also an
How are drugs "absorbed"?
Drugs must get to systemic circulation to be utilized.
Oral meds may be affected by vomiting or diarrhea.
IM will be faster than SQ because of greater vasculature.
Factors that alter bioavailability?
1: the drug form (e.g., tablet, capsule, sustained-release, liquid, transdermalpatch, rectal suppository, inhalation)
2: route of administration (e.g., oral, rectal, topical, parenteral)
3: Gl mucosa and motility
4: food and other drugs
5: changes in liver metabolism caused by liver dysfunction or inadequate hepatic blood flow
Bioavailability?
Percentage of drug that reaches systemic circulation.
For oral drugs that have a high rate of liver metabolism (20-40%), 3 to 5 times the dose ca be required po to match to bioavailability of an IV dose which usually has bioavailability of 100%.
What is the difference between lipid and water soluble drugs? Which of the 2 crosses the cell membrane easily?
The GI membrane of the SI is mostly lipid and protein, so lipid soluable drugs can pass across the membrane via passive diffusion.
Water soluable drugs require a carrier - protein or enzyme - to cross and energy.
Lipid soluable (and non-ionized) drugs are absorbed faster than water-soluable and/or ionized drugs.
What is the pharmaceutic phase of drug action?
It applies only to oral meds and it is the dissolution of the pill, i.e. oral "liquids" are already in solution.
Fillers are called excipients
FDA's Drug Pregnancy Categories
A: No risk to fetus
B: No risk in animal studies; well-controlled studies in pregnant women are not available
C: Animal studies indicate a risk to the fetus. Risk-v-benefit?
D: A risk to the human fetus has been proved; Risk-v-benefit? life-threatening conditions
Z: A risk to the human fetus has been proved. Risk outweighs the benefit
1914 Drug Act
Harrison Narcotics Tax Act
Regulated importation, taxation and distribution of opium
It also stated that docs could write Rx for narcotics for treatment, but not for treatment of addiction
Harrison Narcotics Tax Act
1914
Regulated importation, taxation and distribution of opium
It also stated that docs could write Rx for narcotics for treatment, but not for treatment of addiction
Timeframe for drug to be given on an "empty" stomach?
1 hour before or 2 hours after a meal.
Define pharmacology
The study of effects of chemical subtsances on living tissues
What is a generic name?
The official or nonproprietary name of a drug. It is not owned by any drug company.
Food, Drug, and Cosmetic Act
1938
Empowered FDA
Regulate manufacture & marketing of drugs
Tested for harmful effects
Labels with accurate information
Only safe by FDA approved marketing
1938 Drug Act
Food, Drug, and Cosmetic Act
Empowered FDA
Regulate manufacture & marketing of drugs
Tested for harmful effects
Labels with accurate information
Only safe by FDA approved marketing
Durham - Humphrey Amendment
1952
With or w/o Rx
Refilled only w/ new Rx
1952 Drug Act
Durham - Humphrey Amendment
With or w/o Rx
Refilled only w/ new Rx
Kefauver -Harris Amendment
1962
Thalidomide tragedy of the 1950s
European infants limb deformities
Adverse reactions & contraindications labeled
1962 Drug Act
Kefauver -Harris Amendment
Thalidomide tragedy of the 1950s
European infants limb deformities
Adverse reactions & contraindications labeled
Controlled Substances Act
1970
Prevention & treatment drug dependence
Categories: I thru V
1970 Drug Act
Controlled Substances Act
Prevention & treatment drug dependence
Categories: I thru V
FDA Modernization Act
1997
Review & use accelerated
Tested in children bef marketing
Clinical data necessary for serious
Discontinue drugs 6 months notification
1997 Drug Act
FDA Modernization Act
Review & use accelerated
Tested in children bef marketing
Clinical data necessary for serious
Discontinue drugs 6 months notification
HIPPA
2003
Privacy of individually identifiable health information
2003 Drug Act
HIPPA
Privacy of individually identifiable health information
Medicare Prescription Drug Improvement and Modernization Act
2003
Financial assistance to seniors
2003 Drug Act
Medicare Prescription Drug Improvement and Modernization Act
Financial assistance to seniors
Schedule I Definiton and examples?
High potential for drug abuse.
No accepted medical use.
Labeled C-I.
heroin
LSD
mescaline
marijuana [except when prescribed with cancer treatment], peyote, psilocybin)
Schedule II Definiton and examples?
High potential for drug abuse.
Accepted medical use.
Can lead to strong physical and psychological dependency.
Labeled C-II
meperidine (Demerol) this drug is not used because it causes seizures
morphine
methadone
hydrocodone
hydromorphone
oxycodone
codeine
amphetamines
secobarbital
pentobarbital
Schedule III Definiton and examples?
Medically accepted drugs.
Less potential for abuse is less than that for schedules I and II.