Review of Knowledge- NR 291
Chapters 2-7, 36 & 37; Part 1
Chapter 2: Pharmacologic Principles
“Any chemical that affects the physiologic processes of a living organism can broadly be defined as a drug. The study or science of drugs is known as pharmacology. Without understanding basic pharmacologic principles, the nurse cannot fully appreciate the therapeutic benefits and potential toxicity of drugs. Drugs are grouped together based on their similar properties. This is known as a drug classification. Drugs can be classified by their structure (e.g., beta-adrenergic blockers) or by their therapeutic use (e.g., antibiotics, antihypertensives, antidepressants). Within the broad classification, each class may have subclasses; for example, penicillins are a subclass within the group of antibiotics and beta-adrenergic blockers are a subclass within the group of antihypertensives. Pharmacotherapeutics (also called therapeutics) focuses on the clinical use of drugs to prevent and treat diseases. The following terms are necessary for nurses to know, understand, and apply to their clients”. (Lilley, p. 21) Definitions: Review definitions at the beginning of the chapter. Identify the 4 phases of pharmacokinetics, and explain briefly what occurs in each phase. 1. absorption it is the movement of drug from its site of administration into the blood stream for distribution to the tissue. 2. distribution it is the movement of drug from its site of administration into the blood stream for distribution to the tissue. 3. Metabolism: is referred to as biotransformation. It involves the biochemical alteration of a drug into inactive metabolite a more soluble compound. 4. Excretion: is the elimination of drugs from the body.
The half-life of a drug is the time required for one-half (50%) of a given drug to be removed from the body. It is a measure of the rate at which the drug is eliminated from the body. For instance, if the peak level of a particular drug is 100 mg/L & the measured drug level is 50 mg/L in 8 hours, then the estimated half-life of that drug is 8 hours. (Potter& Perry p. 28) Fill in the boxes:
Half- life is 3 hours
Drug X dose 200 mg
Drug X dose 500 mg
Route of Administration: The parenteral route is the fastest route by which a drug can be absorbed, followed by the enteral and topical routes. Parenteral is a general term meaning any route of administration other than the GI tract. It most commonly refers to injection. Intravenous injection delivers the drug directly into the circulation, where it is distributed with the blood throughout the body. Drugs given by intramuscular injection and subcutaneous injection are absorbed more slowly than those given intravenously
Give reasons why you would use the following routes & which form you would use: (SEE CHART ABOVE FOR FORMULATIONS OF MEDS) Enteral: Reason / Formulation
Parenteral: Reason / Formulation
Topical: Reason / Formulation
Easy administration and more economical.
Delivers medication directly to the affected area.
Example IV route
More likely to be reversed.
Why can’t extended release oral medications be crushed? Because it could cause accelerated release of drugs from the dosage form and possible toxicity. (p. 21) What are enteric-coated tablets not recommended for crushing? Because it could cause disruption of the tablet coating designed to protect the stomach lining from the local effects of the drug and or protect the drug from being prematurely disrupted by stomach acid. How can you help a client who has swallowing difficulties take their oral medication? Check to see if medication can be crushed and mixed with food such as apple sauce or pudding or if there is buccal or sublingual form of medication available and consult with the doctor if it can be substituted. First Pass Effect: “A drug that...
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