Movement of drug from administration site into bloodstream
Movement of drug through the bloodstream to tissues and cells
Conversion of the drug into another substances
Removal of the drug or substance it became from the body
The rate at which drug molecules disappear from the circulatory system, primarily through hepatic (liver) metabolism and renal excretion
Clearance (or clearance rate)
Process during distribution in which a
portion of drug is attracted to and binds to protein, such as albumin in blood,
preventing it from passing through capillary walls; therefore this portion is
inactive and cannot achieve therapeutic effect.
The portion of being distributed in the body that is not bound to protein & therefore is active & can achieve therapeutic effect
Drug molecules that attach to receptors on cells to stimulate the cell to act; they promote function
Drug molecules that attach to receptors & prevent something else from attaching ( block the receptor) and causing an effect
Antagonists or blockers
The amount of time that is required to remove half or 50% of blood concentration of a drug
The point at which the amount of drug that is administered and the amount that is being eliminated from the body balance off. The balance creates a stable level of drug in the blood
The rate at which drug molecule disappear from the circulatory system, primarily through hepatic metabolism and renal excretion
Another term for metabolism of drugs. When drugs are changed from their original form to a new form in the body
Product of metabolism, a drug that is metabolize is generally changed into an inactive form on its way to excretion . Occasionally a drug be metabolized in active metabolites substance that can achieve an independent effect that can be either therapeutic
The rate of metabolism of a drug varies as it is circulated through the bloodstream, to the portal circulation, and through the liver. The percentage of the drug metabolites on the first circulation or pass through the liver is high then the drug loses effectiveness during this first pass before reaches the general circulation. Loss of effectiveness in the first pass
First pass effect
A system of liver enzyme families three of which are involved in drug metabolism. drugs can either induce or inhibit P-450 system altering metabolism of other drugs
A drug's relative pharmacologic activity. The amount of drug that must be given in order to produce a particular response. Highly potent drugs often have a higher affinity for the receptor site on the cell so little is needed to produce its effects
How well a drug produces its desired effect. Is relative to the intrinsic activity. The higher the activity the greater the efficacy
The dose of a drug that is required to produce a therapeutic effect in 50% of the population. Often considered the standard or typical dose and is chosen when the drug therapy is initiated
ED50 Effect dose 50.
The point at which the dose of a drug would be fatal in 50% of the population
LD50 Lethal dose 50
a drug dose that is administered consistently over time, such as every day. Often achieved after 4-5 half-lives.
A higher dose of a drug given initially at the start of drug therapy when the drug has a longer half-life and needs to achieve steady-state in the shortened time frame due to the patient's medical condition requiring immediate steady-state for effective treatment
Ratio comparison used to determine the safety of a drug. The ED 50 is divided by the LD50 in ratio form and if there is little difference between the two the drug has a narrow therapeutic index and is therefore not very safe due to difficulty in dosing the drive safely
An immune system antigens/antibody response after drug is taken again it involves the release of histamine, which leads to allergic signs and symptoms and possibly anaphylaxis; the most serious allergic response
An unusual adverse effect of a drug, can be opposite response from what is anticipated. An individual's unique response to a drug, also called paradoxical effect
When two or more drugs that are alike in therapeutic Effect are combined, and the resulting response is the sum of the drug effects. Can be an intentionally more therapeutic, or unintentionally cause harm
When two or more unlike drugs, in terms of therapeutic effect or mechanism of action, are used together to produce a combined effect. Outcome response is greater then if either was used alone
An interaction between drugs in which one of the two drugs is increased. I.e. A drug that has mild effect may enhance the effects of a second drug
A chemical that can affect living processes
The study of drugs in their interactions with living systems
The study of drugs in humans
The use of drugs to diagnose prevent or treat disease or to prevent pregnancy
Nursing responsibility six rights
In order to anticipate problems the nurse must understand... (3)
1.The patient and the disorder being treated
2. What drugs are contraindicated
3. Probable consequences of the interactions between drugs and patient
Suppress cough reflex
Dextromethorphan (DMX) Pharm. therapeutic
Used to treat constant nonproductive cough
Dextromethorphan (DMX) pharmacodynamic
Directly affects the cough Center in the Medulla
Dextromethorphan (DMX). Contraindications
Chronic cough associated with emphysema and asthma
Dextromethorphan (DMX) adverse effects
Nausea, vomiting, drowsiness, dizziness, irritability, restlessness. Possible poisoning/overdose for euphoric effects
Dextromethorphan (DMX). Drug interactions
Dextromethorphan (DMX) asses
Contraindications (emphysema and asthma)
May cause drowsiness assess for operation of heavy equipment
May impair motor/orientation – help ambulated- safety
Dextromethorphan (DMX) important to asses
Frequently assess respiratory status
Ck for clear airwAy
Oral, at CNS depressant. Works on medullary center
Codeine, hydrocodone contraindications
Post op patients who need to cough and deep breathe and those with chronic cough
Tessalon/ Tessalon perles
Non-narcotic, anesthetizes stretch receptors in respiratory system to reduce cough reflex
Used in endoscopy
Decongestants taken to
decrease nasalcongestion r/t infections/inflammatoryresponse in the upper respiratory tract
Decongestants Work by
constricting nasal arterioles,thereby decreasing the swelling of thenasal membrane & decrease mucus
absorbed in thebody, increasing the chance of adverseeffects
same therapeutic effects as oral; riskadverse effects diminished
Decongestants Prototype drug:
Reduction of volume of nasal mucus, temporary relief of nasal congestion
oral onset 30 min,
topical 5-10 (sympathomimetic*)
Vasoconstriction of nasal arterioles/mucus membranes
Caution with preg./lact. Preg C
Tension, anxiety, restlessness, tremor, insomnia, &weakness (can cause sensory/visual effects in CNS,hallucination, & CV effects
Block the action of histamine released duringinflammatory response to an antigen
Restores normal airflow through the upperrespiratory system
Antihistamines Prototype drug:
Relieves seasonal & perennial allergysymptoms
oral, Peak: 2–6 hours
Selectively blocks the effects of histamine at H1-receptor sites.
^viral infections, nausea, vomiting,dysmenorrhea, dyspepsia, *CNS: drowsinessfatigue, but less anticholinergic/CNS effects b/c2nd generation; *elders, all antihistamines maycause thickened resp. secretions
Rifampin & juices reduce absorption
fexofenadine Assess: For
Hx of Cardio-Vascular (CV) diseasepreg./lact, (class C)& renal status, how often drinksapple, grapefruit, or orange juice
Use as prescribed & caution OTC,Why?, take with full glass H2O/^ fluids, humidifier,avoid juices at adm., caution with OTC, safety forCNS effects, adverse effects decrease after a fewdays, no alcohol, Why?
Antihistamines (Zyrtec) Once a day, a little more sedation
Claritin Antihistamines Once a day, less CNS effects thanfexofenadine.
Antihistamines Clarinex) Longer acting form ofloratadine/claritin, more potent, less CNS effects due to lessaffinity for the H1 receptors in CNS
First Generation Antihistamines
Chlorpheniramine (Chlor-Trimenton, Clemastine(Tavist, twice a day), Dipenhydramine (Benadryl). Most not aslong acting, must take 4+ times a day, sedating, Benadryl oftenused as a sleep aide
GI symptoms, headache, and dizziness, (possible CNSeffects)
Hypers???, preg class C, Assess smoking. No important drug interactions, no alcohol
Good pulmonary hygiene, (coughing,deep breathing, drinking plenty of fluids, humidifier,cough etiquette
eat small, frequent meals to alleviate GI upset,
Explain drug helps makes it easier to cough upsecretions,
Do not use guaifenesin for longer than 1 week forpersistent cough (unless cleared with HC provider)
not for smokers cough, no alcohol, caution OTC,
Assess effectiveness, response, report fever
Expectorants:^ fluid secreted in resp tract, 42%Alcohol, not used much, Contra. preg
Iodine Preparations (SSKI, Potassium iodide)
Expectorants:Used forCOPD, CF, used less, thyroid effects, Preg. Class X
break down mucus
Administered by a nebulizer or by direct instillationinto the trachea.
Reserved for patients who have major difficultymobilizing and coughing up secretions
to liquefy the thick, tenacious secretions
inhalation, Onset: 1 min.
splits disulfide bonds that are responsible forholding the mucous together
Acetylcysteine Adverse effects:
Bronchospasm, bronchoconstriction,chest tightness, burning sensation in upper airway,rhinorrhea
Administer an inhaled beta agonist beforeadministering acetylcysteine
Pregnancy Basic Considerations
Any treatment during pregnancy requirescareful consideration.
• The treatment benefits must be balanced withthe risks of treatment.
• Risk also applies to the fetus.
• Most drugs have NOT been tested duringpregnancy.
• Therefore the risks for most drugs areunknown.
1st priority (legally) baby or mother?
Conditions that threaten the mother’s healthmust be addressed, as the health of the fetusdepends upon the health of the mother.
3rd trimester of pregnancy renal blood flow is doubled:
This can result in accelerated clearance of the drugs.(The dose should be increased to compensate for thisincreased clearance).
Hepatic metabolism also increases during pregnancy.
(Doses need to be adjusted)
Tone and motility of bowels decreases in pregnancy.
This allows for more drug to be absorbed. It alsoallows more time for reabsorption of drugs thatundergo enterohepatic recirculation (drug effects couldbe prolonged).
Essentially ____drugs can cross the placenta...
although some cross more readily than others.
Drugs that are _____ soluble cross the placenta easily.
Drugs that are ____, ____ _____, or ____ ____ cross with difficulty.
or protein bound
production ofbirth defects
Incidence of Congenital Anomalies______
Incidence of major structural abnormalities (lifethreatening or require surgical correction) is between 1-3%
.– ½ are obvious and reported at birth.
– ½ involve internal organs and are not discovered untillater in life or upon autopsy
Cause of Congenital Anomalies include
Genetic predisposition (25% of all defects)
• Environmental chemicals
• Drugs (<1% of all defects)
• The majority of congenital anomalies are fromunknown causes.
Teratogenesis Preimplantation/ presomite period – (Conception throughweek 2)
Teratogensact in an “all-or-nothing” fashion. Ifthe dose is high, death often results. If the dose issublethal, likely to have full recovery.
Teratogenesis Embryonic period (week 3 – 8/ first trimester)
Exposure toteratogensat this stage often produce gross malformations.Mothers must be very careful in the first trimester.
Teratogenesis Fetal period (week 9 to term)-
Exposure often disruptsfunction rather than gross anatomy. Growth anddevelopment of the brain are especially important in thisstage (can cause learning disabilities and behavioralabnormalities).
Only a few drugs are considered ________teratogens.
Lack of proof of teratogenicity does NOT mean that a drug is safe (only that available data is insufficient to make a decision).
To prove that a drug is a teratogen, three criteria must be met:
Drug must cause a characteristic set of malformations
• Must act only during a specific window of vulnerability (weeks 4-7 of gestation)
.• The incidence of malformations should increase with increasing dosage and duration of exposure.
Drugs are put into one of five risk categories:
A,B, C, D, and X.
Category ___ is the least dangerous, with the risk _______ as you progress through the alphabet.
Category __ are drugs known to cause fetal harm,and their risk to the fetus outweighs any possible therapeutic benefit.
FDA Pregnancy Risk Category A
Remote risk of fetal harm. Controlled studies in women have been done andhave failed to demonstrate a risk of fetal harm during the first trimester, andthere is no evidence of risk in later trimester.
FDA Pregnancy Risk Category B
Slightly more risk than A. Animal studies show no fetal risk but controlled studieshave not been done in women.
Animal studies do show a risk of fetal harm but controlled studies in women have failed to demonstrate a risk during the first trimester and there is no evidence of risk in later trimesters.
FDA Pregnancy Risk Category C
Greater risk than B: Animal studies show a risk of fetal harm, but no controlled studies have been done in women. ORNo studies have been done in women or animals.
FDA Pregnancy Risk Category D
Proven risk of fetal harm. Studies in women show proof of fetal damage, but the potential benefits of use during pregnancy may be acceptable despite the risk (treatment of life-threatening disease for which safer drugs are ineffective).WARNING will appear on drug label.
FDA Pregnancy Risk Category X
Proven risk of fetal harm. Studies in women or animals show definite risk of fetal abnormality. OR Adverse reaction reports indicate evidence of fetal risk.The risks clearly outweigh the benefit. CONTRADICTION will appear on drug label.
The first step Responding to Teratogen Exposure
after exposure is to determine when the pt became pregnant and when the drug was taken.
If exposure was not during weeks 3-8, the pt should be reassured that the risk is minimal.
Drugs that are ____ ____ enter breast milk more readily.
Drugs that____, ____ ____ or ____ ____ are tend to be excluded. from passing into breast milk
ionized, highly polar, or protein bound
Dosing immediately____ breast-feeding to minimize drug concentrations in milk at the next feedin
The study of drug movement throughout thebody.•
Also involves drug metabolism and excretion.
Combination of metabolism plus excretion is called:
Three ways to cross cell membranes:
-Passage through channels or pores - rare (too small)
-Passage with aid of a transport system
-Direct Penetration of the membrane
Direct Penetration of the membrane
– Most common because most drugs are too big to pass through channels/pores.
– Most drugs lack transport systems.
Drugs MUST be ____ ____ (____)to penetrate cell membranes
lipid soluble (lipophilic)
Polar Molecules “Like dissolves like”
Polar molecules will dissolvein Polar solvents (water) but not in nonpolarsolvents (oil).– Cannot get through the lipid (oil/ fat) membranethat surrounds cells
Factors affecting drug absorption:
Rate of dissolution
Rate of dissolution
Faster a drug can dissolve, the quickerit can be absorbed
Area available for absorption, more area =faster absorption
More blood flow = more absorption.
Highly lipid-soluble drugs are absorbed faster. (penetrate membranes)
Absorption is enhanced when thedifference in pH is more favorable in the blood plasmathan site of administration. (Acidic oral medications tendto be absorbed faster because the blood is more basic thanthe stomach).
Generic medications have the same ____ _____, but not always the same
chemical equivalency, bioavailability.
Contain the same AMOUNT of the identical drug.
– Drug is ABSORBED at the same rate and extent.
Drug is covered with materialdesigned to dissolve in intestines NOT stomach.
Distribution Determined by three major factors:
– Blood flow to tissues
– Ability of drug to exit the vascular system
– Ability of drug to enter cells.
The capillaries in the brain have tight junctions that prevent drugs passing between the capillary cells. (Unique to the brain).
Blood-Brain Barrier (BBB)
Only ____ _____ (____) drugs or drugs with a ____ ____ can cross the BBB. (______drugs do not crosswell.)
Lipid Soluble (lipophillic); Transport System: Hydrophyllic
____do not have a fully developed BBB, so they are highly sensitive to meds that act on the brain and CNS poisons.
Lipid-soluble, nonionized compounds ____ ____to the fetus.
The importance of protein binding is that
drug distribution will be restricted.
Bound drug molecules cannot leave thebloodstream and therefore cannot be used.
Drug metabolism has six possible consequences of therapeutic significance:
– Accelerated renal excretion of drugs
– Drug inactivation
– Increased therapeutic action
– Activation of “prodrugs”
– Increased toxicity
– Decreased toxicity
The most important consequence of drug metabolism is
promotion of renal drug excretion.
Metabolism can convert active drug compounds into inactive forms.
Metabolism can increase the effectiveness of some drugs.
Increased Therapeutic Action
A prodrug is a compound that is pharmacologically inactive when administered and then is converted to its active form within the body.
Activation of Prodrugs
Converting drugs to inactive forms can decrease toxicity. Metabolism can alsoincrease the toxicity by converting safe compounds into toxicforms. (Tylenol)
Increased or Decreased Toxicity
Rapid hepatic inactivation of certain oral drugs.
Minimum Effective Concentration (MEC)
The plasma drug level below which therapeuticeffects will NOT occur.
– Drug level must be above the MEC to providebenefit.
– The plasma drug level at which toxic effects begin.
– Drug levels must be below toxic concentration to prevent harm.
Dose-response relationship has three phases:
Phase 1 – Occurs at low doses, the curve is flat because doses are too low to elict a measured response. (sub therapeutic)
Phase 2 – An increase in dose elicts a correspondingincrease in response. This phase during which the dose-response relationship is graded.
Phase 3 – As the dose goes higher, we eventually reach a point where an increase in dose is unable to elicit a further increase in response. The curve flattens.
The largest effect that a drug can produce.
The intensity of the responseto a drug is proportional to the number of receptorsoccupied by that drug and that a maximal response willoccur when all available receptors have been occupied.(Does not explain why one drug is more potent thananother or have higher efficacy than another).
Simple Occupancy Theory:
Ascribes affinity and intrinsicactivity that describe the ability of a drug to bind to thereceptor and the ability to influence receptor function
Modified Occupancy Theory
The strength of attraction between a drug and its receptor.
Drugs with ____ affinity are ____ attracted to their receptors.
Drugs with ___ affinity are ____potent.
Refers to the ability of a drug to activate the receptor following binding.
Drugs with ____ intrinsic activity cause ______receptor activation.This relates to the ____ efficacy.
high; intense: maximal
Two drugs can occupy the same number of receptors but the drug with the _____ intrinsic activity will produce more intense responses.
MIMIC the body’s own regulatory molecules.
BLOCK the body’s own regulatory molecule.
_____ have Affinity for a receptor but no intrinsic activity.
Has both affinity and high intrinsic activity.
Most _____ are competitive
Noncompetitve antagonists bind _____ to receptors.
________ (Surmountable) Antagonists• Bind reversibly to receptors.
Neonates and Infants:Because organ systems that regulate drug levels are not fully developed, these patients are at risk of more____ & ____effects.
intense and prolonged
Drug-metabolizing capacity of newborns is ____
Two main types of lower respiratory drugs
Anti-inflammatory agents and bronchodilators
Principal anti-inflammatory agents are
Principal broncodilators are
Three advantages of inhalation
Therapeutic effects are enhanced, delivered directly to site of action – local