PP #5 Pharmacotherapeutics

Pharmacodynamics

"what the drug does to the body" the relationship between drug concentration at the site of action and the resulting effect, including the time course and intensity of therapeutic and adverse effects - how medications achieve their effects at various sites in the body - Includes the time course and intensity of therapeutic and adverse effects

While preparing to irrigate a client's ears, the nurse instructs the client to: 1. Expect a feeling of fullness in her ears 2. Tilt the head forward 3. Lie in a prone position 4. Expect a cold sensation

1 Rationale: The client is positioned in a sitting or side-lying position with the head turned toward the affected ear. Prewarm the solution for client comfort.

An infant of 11 months is to receive a penicillin injection. The nurse prepares which muscle for injection? 1. Ventrogluteal 2. Vastus lateralus 3. Dorsogluteal 4. Rectus femoris

1 Rationale: The ventrogluteal is the preferred site for most intramuscular injections from age 7 months to adult. Advantages of this site are listed in the section that reviews the use of each site.

Nurses' roles (5)

1. Administer 2. Evaluate 3. Educate 4. Manage 5. Monitor

5 Rights of Rx Administration

1. Right drug 2. Right pt. 3. Right dose 4. Right route 5. Right time sometimes there's a 6th? 6. Right documentation

Intramuscular Demerol (meperidine) is injected correctly when the nurse: 1. Cleans the site with an antiseptic swab in a circular motion, starting from the outside moving into the center 2. Uses the nondominant hand to pull the skin 2.5 centimeters (one inch) to the side of the injection site 3. Inserts the needle using a slow, steady motion into the muscle to avoid excess pain 4. Aspirates by pulling back on the plunger of the syringe until a drop of blood appears at the hub

2 Rationale: Using the principle of cleanest to dirty, the cleaning begins at the injection site and moves outward in a circular manner (option 1). The needle of an intramuscular injection is inserted rapidly to avoid pain. Blood is not expected with aspiration (option 3); if seen, it indicates the needle may be in a blood vessel, and the needle is withdrawn before the medication is administered (option 4).

The nurse performs a subdermal allergy test correctly if the nurse: 1. Inserts the needle at a 25-degree angle 2. Massages the allergen into the tissue after administration 3. Injects the allergen rapidly in order to form a wheal 4. Forms a bleb under the epidermis

3 Rationale: For allergy testing, the needle is inserted at a 15-degree angle; the allergen is injected slowly to allow a wheal to form; do not massage. Allow the allergen to be absorbed naturally.

A medication order reads, "Restoril 15mg hs prn". The nurse gives the medication: 1. Before meals at the nurse's discretion 2. After meals at the patient's request 3. At bedtime as needed 4. Immediately as ordered

3 Rationale: Many abbreviations are used whenever medication orders are written, transcribed, and followed. Nurses must understand the abbreviations in order to interpret the instructions correctly. The abbreviations in Table 35-7 must be learned and applied when administering medications. In addition to this table, institutions may use different abbreviations. A nurse needs to become familiar with the institution's own acceptable abbreviations and use those exclusively to avoid medication error.

A client tells the nurse, "These pills don't look like the ones I usually take." The nurse says: 1. "Go ahead and take it. It's the generic variety." 2. "Take the pills that you recognize and leave the rest." 3. "I'll take these back and recheck your medications." 4. "For now, just take the ones you recognize."

3 Rationale: Most clients are familiar with the medications they take. Sometimes, generic medications or different brands of medications are given in hospitals, but do not assume this is the reason for medications looking different. Do not rely on appearances, as some medications look similar but actually are different. If there is any question about a medication, do not give the medication until the question is answered.

The nurse uses the following landmarks when using the ventrogluteal muscle for intramuscular injection: 1. Lateral femoral condyle, iliac crest, anterior iliac spine 2. Lateral femoral condyle, greater trochanter, posterior iliac spine 3. Greater trochanter, iliac crest, anterior superior iliac spine 4. Greater trochanter, lateral femoral condyle, posterior superior iliac spine

3 Rationale: The various landmarks used to identify intramuscular injection sites may be shared physically, and have similar names that may confuse those first learning them. It is crucial that students be able to identify landmarks by name and by site in order to prevent injury.

The nurse is to administer morphine sulfate intravenous (IV) push into an existing IV of 5% dextrose and .45% normal saline running at a rate of 125 ml/hour. The nurse injects the morphine sulfate into the injection port that is: 1. Closest to the IV pump 2. Closest to the IV clam 3. Just above the filter 4. Closest to the client

4 Rationale: Medication given by IV push is best given as close to the client's circulation as possible. Answers 1, 2, and 3 are sites more distant.

How to prevent med errors

APIE Assessment: Right dose, time, route, renal and liver function Planning: Does the patient know why they are taking the medication? Implementation: Is it the "right" pill? Evaluation: Did the medication have the expected outcome? Any adverse outcomes?

Rated risk in pregnancy (6 categories)

Category A: Adequate and well-controlled studies have failed to demonstrate a risk to the fetus in the first trimester of pregnancy (and there is no evidence of risk in later trimesters). Category B: Animal reproduction studies have failed to demonstrate a risk to the fetus and there are no adequate and well-controlled studies in pregnant women. Category C: Animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks. Category D: There is positive evidence of human fetal risk based on adverse reaction data from investigational or marketing experience or studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks. Category X: Studies demonstrate fetal abnormalities and/or there is positive evidence of human fetal risk based on adverse reaction data from investigational or marketing experience, and the risks involved in use of the drug in pregnant women clearly outweigh potential benefits. Category N: FDA has not classified the drug

Clinical trial/Drug development

Pre-discovery - based on disease focus, scientists work to better understand the disease Drug-discovery - researchers select a target, such as a gene or a protein, then search for a molecule or compound that may act on the target and alter the disease (4-5 years) Pre-clinical testing - early safety and efficacy tests done via computer models, cells and in animals Phase 1 clinical trial - tested in people for the first time with approx. 20-100 healthy volunteers Phase 2 clinical trial - researchers evaluate the medicine's efficacy in approx. 100-500 patients with the disease Phase 3 clinical trial - researchers study the medicine in 1000-5000 patients to generate data about safety, efficacy and the overall benefit-risk relationship of the medicine Phase 4 - adverse reactions, surveillance, product defect reporting

5 US Drug Schedules

Schedule I drugs or substances have a high potential for abuse. There is a lack of accepted protection for use of the drug under this category. Examples are heroin, lysergic acid diethylamide (LSD), marijuana. Schedule II drugs or other substance also have a high potential for abuse and they do have a currently accepted medical use in treatment. Examples are morphine, phencyclidine (PCP), cocaine and methadone. Schedule III drugs or other substances have less potential for abuse than the drugs or other substances in schedules I and II. Abuse of these drug or other substance may lead to moderate or low physical dependence or high psychological dependence. Examples are Anabolic steroids, codeine and hydrocodone with aspirin or Tylenol. Schedule IV drugs or substances have a comparatively low potential for abuse relative to the drugs or other substances as in Schedule III. Examples are Darvon, Talwin, Equanil, Valium, and Xanax. Schedule V Drugs have relatively lower abuse potential, medical use, limited dependence risk. Examples are cough medicines with codeine.

Onset of action

Time needed for effects of drug to appear

Lethal dosage (LD50)

amount of a pharmaceutical that would kill 50 % of the population

Effective dosage (ED50)

amount of a pharmaceutical that would produce a therapeutic response in 50 % of the population

Therapeutic level

concentration of a drug in blood serum that produces desired effect without toxicity

Drug classes

groups of drugs that share common actions or mechanisms ex) anti-inflammatory, antihypertensives, antibiotics, antidepressants

Biological half-life

how long it takes for the body to get rid of 1/2 the drug - help determine how often to dose - completely eliminated after 4-5 half-lives - the effects of a drug typically begin to taper off as the first half-life point is reached

Duration of action

length of effect

Controlled substances

narcotics, depressants, stimulants, hallucinogens, anabolic steroids - DEA is responsible - 5 schedules/classes - Governed by law - Kept locked up - Recorded: Patient's name, date, time of administration, drug, dose, nurses' signature, verifying signature, verified number available with number indicated on inventory record

Peak level

serum blood level as drug reaches its peak therapeutic affect; the highest level of effectiveness - generally collected 1/2 hour-2 hrs after the dose is given via IV or 1 hr after IM

Drug potency

the drug with the lower EC50 is more potent - a lesser amount of a more potent drug is needed to achieve the same effect as a less potent drug

Therapeutic effect

the drug's usefulness in treating particular diseases - what it does clinically ex) Ibuprofen = pain relief, fever reduction, reduce swelling

Trough level

the lowest amount of a drug present in the bloodstream that still exerts a therapeutic effect (right before next dose is due) - generally collected right before the next dose - if it is higher than normal, pt. is at risk for adverse effects

Therapeutic window

the range of doses of a drug that are actually effective in treating a particular disease

Therapeutic index

the ratio between the dosage of a drug that causes a lethal effect and the dosage that causes a therapeutic effect - narrow therapeutic index = a very close margin between the concentration in the blood circulation of a drug that is therapeutic and the concentration that is lethal

Pharmacologic effect

the way the drug works in the body - its mechanism of action ex) Ibuprofen = non-steroidal-anti-inflammatory (NSAID)

Pharmacokinetics

what the body does to the drug ADME --> absorb, distribute, metabolize, excrete

Peak action

when concentration of drug is highest in the blood