NURS 2004 Pharmacology Midterm

Comprehensive NURS 2004 Pharmacology Midterm Exam Study Tool

Drug

Any chemical that can effect the living processes

Pharmacology

The study of drugs and their interactions with living systems

Pharmacotherapeutics

Use of drugs to diagnose, prevent or treat disease, or prevent pregnancy

Chemical Name

Name of the chemical composition of a drug

Generic Name

Name of a drug as assigned by the united states “adopted name council” (same names used in Canada)

Trade Name

Proprietary name of a drug chosen by the company

Three basic properties of drugs

1. They do not modify existing functions in the body (They DO NOT change the body)

2. They exert their functions on multiple systems (Side effects)

3. They interact with molecules which are normal points of control of physiological processes (how they work)

Risk to benefit ratio

Benefits must always outweigh the risk of a drug

How should you most safely prescribe a new drug to a patient (4)

1. Use single action drugs when possible

2. Start with lowest dose

3. Individualize treatment to the patient

4. Monitor the effects (positive and negative)

What are the steps of the Nursing Process

Assessment

Diagnosis

Planning

Implementation

Evaluation

What should happen during the Assessment portion of the nursing process (Pharmacology related)

Take a medical history

Identify possible risks for the patient (allergies, genetics…)

What should happen during the Planning portion of the nursing process (Pharmacology related)

Observe the appropriateness of a prescribed drug (dangers, risks…)

What should happen during the Implementation portion of the nursing process (Pharmacology related)

Identify which interventions should be implemented

Conduct the 10 rights and 3 checks

Assess the patients capacity for self-care

What are the 10 rights of medications?

1. Right Patient

2. Right Medication

3. Right Dose

4. Right Time

5. Right Route

6. Right Assessment

7. Right Evaluation

8. Right Education

9. Right to Refuse

10. Right Documentation

When do you do the 3 medication checks?

1. When you get the medication

2. When you’ve drawn your medication

3. At the bedside BEFORE giving the medication

What should happen during the Evaluation portion of the nursing process (Pharmacology related)

Implement non-drug therapies as well

Verify satisfaction with the drug

Observe adverse reactions / interactions

Pharmacokinetics

The movement of drugs throughout the body

Pharmacodynamics

The molecular effect of drugs on the body (what the drug does when it gets to where it needs to go)

What are 2 sources of individual variation that determine the intensity of drug responses?

1. Pharmacokinetics (absorption, distribution, metabolism excretion)

2. Pharmacodynamics (drug receptor interaction)

What are the 4 major pharmacokinetic processes?

1. Drug absorption

2. Drug Distribution

3. Drug metabolism

4. Drug secretion

In what 3 ways do drugs cross the biological membranes of cells?

1. Through the cell membrane

2. Through channels / ports

3. With the aid of transport systems

What 5 factors affect drug absorption

1. Rate of dissolution

2. Surface area

3. Blood flow to admission site

4. Lipid solubility

5. pH

If a drug is LOW protein binding, should you give a higher or lower dose?

Lower dose, because there are more free radicals to bind to sites

If a drug us HIGH protein binding, should you give a higher or lower dose?

Higher dose, because there are less free radicals (they’re all binding to proteins)

Biotransformation

The chemical changing of a drug

What are 3 examples of what effect drug metabolism?

Liver function

Lifestyle (substance abuse)

Diseases

Hepatic first pass effect

When the liver absorbs a medication, and reduces the amount of drug that reaches the bloodstream

What 3 processes occur in the kidney to excrete drugs

1. Glomerular Filtration

2. Passive tubular reabsorption

3. Active tubular secretion

Can lipids move through the kidneys?

No

Within kidney disease, are there more or less nephrons

Less nephrons, meaning less filtration sites

What happens to blood - drug levels when the kidneys are no longer working as they should

Duration and intensity of drugs can increase

What are non-renal routes of drug excretion?

Breast milk, bile, lungs, sweat and saliva

Onset

How long it takes for a drug to start taking effect

Peak

Point in time where a drug is working best - when the highest dose is in the blood

Duration

How long a drug has a therapeutic effect on the body

Therapeutic Range

Optimal range for medication concentration in the blood plasma, which falls between Minimum effective concentration and Toxic concentration

Loading dose

Attains quicker therapeutic action, and is followed by lower maintenance doses to maintain a therapeutic drug plasma concentration

Half Life

The time required for the amount of drug in the body to decrease by 50%

If a drug had a LONGER half life, would it take more or less time for it to leave the body

Longer, because it takes more time for the drug to leave the body

If a drug had a SHORTER half life, would you have shorter or longer intervals of doses?

Shorter, because to maintain therapeutic levels, more doses would need to be administered as it leaves the body quickly

If you give 50mg of morphine (3 hour half-life) to a patient, how many mg would remain in the blood after 9 hours?

6.25mg

Plateau Principle

The maintained level of a drug in the blood plasma after repeatedly administering doses. This means the amount of drug excreted is equal to that of the administered dose.

How many half lives does it take for a drug to reach it’s plateau?

4

What are the 8 factors that affect therapeutic drug levels?

1. A drugs half life

2. Dosing frequency

3. Plasma drug levels

4. Dosage amount

5. Rate of absorption

6. Route

7. Patient’s metabolism

8. Excretion of the drug

Dose-Response Relationships

The relationship between the administered dose and the intensity of the response produced.

What is the benefit of observing Dose-Response relationships

To identify the minimal amount of drug needed to get the maximum response

Maximal efficacy

The largest effect that a drug can produce (no longer any more effective if we add more drug)

Relative Potency

The amount of drug that needs to be in the blood plasma to have an effect on the body

Efficacy vs Potency

Efficacy: How well one dose works in a patient

Potency: How much drug is needed for the effect of the drug to become beneficial

Agonist

Medication that has molecules which bind to, and activate receptors to mimic the action of the body’s own regulatory molecules

Antagonist

Medication that has molecules which block receptor activation that happens in the body’s own regulatory mechanisms

Can drug interactions occur with over the counter medications?

Yes, taking more than one medication (even if not prescribed) can lead to drug interactions

Are drug interaction always negative

No, some drug interactions can be desired

What are non-pharmacological examples of things that can cause drug interactions

Caffeine, nicotine, alcohol, recreational drugs

What two medication can be taken together to INCREASE THERAPEUTIC effects

Sulbactam and Ampicillin

What two medications can be taken together to INCREASE ADVERSE effects

Aspirin and Warfarin

Through what 4 basic mechanisms do drug interactions occur?

1. Direct chemical / physical interactions (eg., mixing)

2. Pharmacokinetic interactions (one drug alters the concentration of another)

3. Pharmacodynamic interactions (One drug alters the effect of another)

4. Combined toxicity

Is it okay to administer a drug which has formed a precipitate upon combination of two or more drugs?

No, you should never administer a precipitate

What 6 kinds of drugs will alter absorption of other medications

1. Drugs that elevate gastric pH

2. Laxatives (if absorbed in intestines)

3. Drugs that suppress peristalsis (giving more/less time for absorption)

4. Drugs that induce vomiting (IV or injection would be more preferable in this case)

5. Drugs that absorb other drugs

6. Drugs that reduce regional blood flow

What can cause altered distribution of drugs?

Competition for protein binding sites

P-glycoproteins (PGPs)

Transmembrane protein that transports a wide variety of drugs OUT of cells

Increased levels of P-glycoproteins (PGPs) can effect what 5 things?

1. Intestinal epithelium (absorption in the intestine)

2. Placenta (drug export from placental cells to maternal cells)

3. Blood brain barrier (drug export from cells of brain in the capillaries into the blood)

4. Liver (blood export from liver into bile)

5. Kidney Tubules (drug export from renal tubular cells into urine)

What are 6 ways a nurse can minimize drug interactions?

1. Minimize the amount of drugs a patient is taking

2. Take a thorough drug history

3. Be aware of possible “hidden” drug use

4. Adjust dosage as metabolizing inducers or protein binding drugs are added

5. Adjust the timing of administration

6. Monitor for signs of early toxicity

What does Grapefruit Juice do to drug metabolism

Inhibits drug metabolism (When you cant metabolize a drug there is more in the blood)

If a medication states it should be taken BEFORE a meal, how early should you take it?

Approximately 1 hour BEFORE the meal (DIFFERENT FOR INSULIN!!!)

If the medication states it should be taken AFTER a meal, how long should you wait to eat?

Approximately 2 hours AFTER a meal

Can medications interact with herbal medications?

Yes, nearly everything in the body can interact with medications in the body. Herbal medicine interactions are just as likely as drug interactions

Adverse drug reactions

Any reaction to a drug that is an undesired effect (excludes excessive dosing). These effects range from annoying to life threatening

What patients are at highest risk for adverse drug reactions

Young patients and the elderly

Neutropienia

Low neutrophil count which leads to increased risk of infection

Allergic reactions are caused by what?

The degree of sensitization of the immune system - not the drug dosage (Immune response DOES NOT occur at first exposure, because you NEED to create antibodies FIRST)

Is a patient’s sensitivity to a drug the same throughout the lifespan?

No, a patients sensitivity can change over time

Idiosyncratic effect

An uncommon drug response resulting from a genetic predisposition (usually brief)

Physical dependance to a drug

Develops over long term use of certain drugs where the body had adapted to drug exposure where the drug is needed to function properly

Abstinence Syndrome

Results when drug use is discontinued

What is the difference between addiction and Abstinence syndrome?

Addiction: Withdrawal from drugs with phycological component of dependance

Abstinence syndrome: Withdrawal of drugs with physical component of dependance

Carcinogenic effect

Cancer causing

Remember benefit MUST outweigh the risk

Teratogenic effect

Drug-Induced birth effect (or miscarriage)

Hepatotoxic drugs

Drugs that are converted to toxic products that injure liver cells (VERY important to monitor for liver failure - jaundice, dark urine, light colored stools, vomiting, abdominal discomfort)

QT heart intervals

Measure of time required for the ventricles to repolarize after each contraction

QT drugs

The ability of some drugs to prolong the QT interval on ECGs

How many QT drugs are acceptable to use at the same time?

Only ever give ONE QT DRUG at a time

What are 3 factors that affect individual variation in drug responses

1. Body weight and composition

2. Body surface area

3. Age

How can kidney disease affect drug levels in the blood?

Kidney disease causes poor kidney function, which means increased toxicity (blood-drug levels)

How can liver disease affect drug levels in the blood?

Liver disease causes poor metabolic activity, which means increased blood toxicity

How can Acid-Base imbalances affect drug levels in the blood?

pH changes can alter absorption, distribution, metabolism, and excretion of drugs

What is an expected blood pH levels?

7.35 - 7.45

How is tolerance developed in patients?

Decreased responsiveness to a drug (caused by receptor changes) as a result of repeated drug administration

What are the 3 types of drug tolerance?

1. Pharmacodynamic tolerance (less sensitive to drug presence

2. Metabolic tolerance (accelerated drug metabolism)

3. Tachyphylaxis (caused by repeated dosing over a short time)

Bioavailability

The extent to which a drug becomes completely available to its intended biological destination(s).

Pharmacogenomics

The study of how genes affect individual drug responses

What 3 things can cause a variation in drug responses

1. Failure to take medication as prescribed

2. Drug interactions

3. Diet

What is peptic ulcer disease (PUD)

Erosion of the gut wall

When does peptic ulcer disease (PUD) occur

When any region is exposed to acid’s pepsin

What places are most common for peptic ulcer disease (PUD)

The lesser curvature of the stomach and the duodenum

What are the signs and symptoms of peptic ulcer disease (PUD)

Abdominal pain after a meal or on an empty stomach

Abdominal pain relieved by food or antacids

Weight loss or poor appetite

Bloating, nausea, poor appetite

Gastrointestinal bleeding (in severe cases) resulting in vomit in blood, or stool

What is the leading defensive factor for peptic ulcer disease (PUD)

Prostaglandins, which stimulate mucus production and vasodilation while suppressing secretion of gastric acids

What can H. Pylori cause?

Peptic ulcer disease

What are the classes of antiulcer drugs?

1. Antibiotics

2. Anti-secretory agents

3. Mucosal protectants

4. Antacids

5. Histamine (H2) receptor antagonists

Famotidine (Pepcid) MOA

Prevents stimulation of the H+ receptors, decreasing acid concentration, and production of gastric acid. Usually given PO.