205: med admin, pain class notes

GENERAL PRINCIPLES OF MEDICATION ADMINISTRATION AND DRUG CALCULATIONS

Objectives: Upon completion of this class, the student will be able to:

1. describe the neurophysiology of pain;
2. discuss interdisciplinary care of the client in pain;
3. describe legal aspects of administration of medications;
4. describe various routes of drug administration;
5. identify essential parts of a medication order;
6. describe the ten rights of safe drug administration;
7. discuss legal charting of medications;
8. identify correct conversions among metric, apothecary, and household systems;
9. select a formula, basic formula, ratio-and-proportion method, fractional equation, or dimensional analysis for calculating drug dosages;
10. convert all measures to the same unit or measure within the system before calculating drug dosage;
11. calculate oral dosages from tablets, capsules, and liquids with selected formula;
12. given specific drug problems, accurately complete drug calculations.

We give meds only in the presence of an RN or LVN…even as seniors.

I. PAIN

If you don’t manage it well, you’ll have a pt with chronic pain—pain pathways get set up and acute pain becomes chronic and prevention is key.

1. Neurophysiology: nociceptors are nerves that respond to pain/noxious sensation. They are in all tissues, throughout the body except the brain; but esp in the skin and muscles. They respond to biologic, mechanical, thermal, electrical, and chemical factors. They also respond to the chemicals released by damaged cells. Major chemical activators of nociceptors: bradykinin, prostaglandins, histamine, etc.

1. pain is perceived through sensory neurons and responded to through motor neurons: like the reflex to draw your hands away from the flame.
2. nociceptors: in the skin. All they do is respond to noxious stimuli [fancy term for pain]
3. pain stimuli: what are they? cutting, ischemia/lack of oxygen [angina], stretching, all are noxious. Temperature. Obstructions [bowel, kidney], cramping [contractions]
4. pain pathway: what is it? Well described in the book: goes to spinal cord. Impulses pass through the medulla and midbrain to the thalamus. In the thalamus and cerebral cortex, the impulses are received and interpreted. The noxious impulse becomes pain when it reaches conscious levels and is evaluated for the person.
5. endorphins: why are they important? Endogenous morphines. Endorphins are our dope—they fit to the receptors that block the pain signals getting to the brain. When you give meds for pain, tell people why you’re giving them: positive placebo effect works up to 50%.
6. pain theory: close the gate to pain: this pain theory is most commonly accepted. These 2 guys found out there are 2 different fibers. “first pain” is felt by A-delta fibers; that’s acute pain—burns stabs, etc—and these are myelenated fibers. Smaller C fibers; these transmit that dull pain after the initial signals or from viscera; chronic pain. Non-pain fibers too, these are called A-beta. These transmit touch, temperature. The theory is that if you stimulate non-pain fibers during pain, you confuse the brain by creating competition in the brain.

2. Types

1. acute: what patients will you be caring for who have acute pain? Why? Tissue injury creates acute pain—b/c skin is full of nociceptors—it’s their job to sense pain. Right now. Up to 6 months [which seems a little long.] Usually this is about tissue injury; post-op, etc
2. chronic: is it as severe as acute pain? Longer than 6 months. Sometimes its about longstanding illness creating pain (cancer): or long healing process from illness/injury. Not always regarding a cause, as in nonmalignant chronic pain: those nerve fibers get used to being stimulated and the acute becomes chronic. What creates chronic pain if it’s not injury? The remaining neurons still being stimulated—like in phantom limb pain.

3. Factors affecting response to pain

1. age: nociception unchanged with aging: old people still feel pain, babies still feel pain.
2. emotional state: stress decreases coping
3. past experiences with pain: just like placebo; the expectation of pain can amplify it via frontal lobe
4. source and meaning: I have cancer and I have more pain, therefore I must not be getting better, tumor’s getting bigger, etc.
5. knowledge: pts need education about their pain, its source, and management, to relieve anxiety
6. cultural: macho men, loud cultures express loudly, quiet cultures express quietly

4. Interdisciplinary Approach

1. medications
2. surgery
3. TENS: nerve stimulators: to stimulate non-pain fibers.
4. complementary approaches
5. nursing process

You will assess pain on everyone all the time. Mod-Severe pain best managed by opioids. Low pain: Tylenols, NSAIDS: When cells are damaged they trigger prostaglandins that tell the brain about pain.

We always trust the patient- we’ve done a bad job managing pain in hx b/c we assume people are drug seeking or addicts. Be non-judgemental

Nerve pain: is neuro pain; that’s like the phantom limb thing. Best treated with some anticonvulsants.

1. assessment: 5^th VS; JCAHO mandate; 0-10 scale; ‘whatever the client says it is’; physiologic and behavioral responses.

• You have to assess pain; it’s the 5^th vital sign. It’s becoming the total legal standard. If you have a pt with a hip replacement, they might be zero at rest but 8 with movement. If someone has drug-seeking behavior, and probably high tolerance, you’ve got the doc on your side.
• Signs of pain: tachycardia, grimacing,
• Ask what the pain is like, and WHERE it is. Don’t make up their pain is related to their c/c.
• You can write non-verbal pain expression
• If meds are PRN Q4hrs for Pain, you’d better assess every 4 hours

2. nursing diagnoses: pain
3. planning: reduce his pain to the level that is_________
4. interventions: pre medicate, educate, etc.
5. evaluation

II. SAFE MEDICATION ADMINISTRATION

1. Legal Aspects

1. FDA: decides that drugs are safe to release based on human studies [largely w/ young healthy males.
2. Controlled Substance Act: drugs locked up and accounted for.

2. Effects of drugs

1. therapeutic
2. side effect: unintentional but maybe desireable
3. adverse effect: bad unintended effect
4. drug toxicity: too much good thing
5. drug allergy: allergic reactions
6. drug tolerance: lower response from repeated use. Usually about receptors being overloaded—fewer receptors on cells to connect to; physiological change
7. drug interaction: drugs change each other’s effect
8. drug misuse:

3. Actions of drugs

1. onset
2. duration
3. peak plasma level
4. half-life

4. Pharmacokinetics: where and how?

1. absorption
2. distribution
3. metabolism
4. excretion

5. Factors affection drug action
6. Ten rights

III. ROUTES OF ADMINISTRATION

1. Oral: most common: why is it most common? It’s convenient. Liquids are available sooner than pills. Coated time release/slow release drugs; how to do crushing for g tube? As a SN we ask the RN or instructor, as a RN we’ll go to the doc or PhmD.
2. Sublingual
3. Buccal; think chewing tobacco
4. Parenteral: by needle: IV, IM, SubQ. IVs are nice for giving pain medsd because they don’t hurt. Flu shots are IM. SubQ: heparin, insulin
5. Topical: convenient. Sometimes can develop tolerance. “Body cavities” means suppositories, oral, eyes, etc.
6. Better; drug given where it is needed. Bronchodilators best inhaled.

IV. MEDICATION ORDERS

1. Types: stat [now], single, standing [all meds available in say, an ICU setting, that RNs can deliver to any pt [barring allergies, etc] as need arises w/o calling the doc], prn [as needed]
2. Parts of drug order: what are they? Drug name, pt name, doc signature, timing, route, dose

V. PREPARATION FOR MEDICATION ADMINISTRATION

Ask if you ain’t sure. Don’t DO IT until you’re totally sure. Ask someone other than the doc first. And probably second. As you get experience you’ll get used to what makes sense.

1. Check MD order and client MAR: at beginning of shift, after MD visit, right before giving meds. Check chart/kardex too in case the change isn’t in the MAR yet. Start at top of MAR. Check label 3x: when it’s out of the drawer, when you’re prepping it, and when you put it back in the drawer.
2. Identify any unfamiliar drugs and research them
3. Review chart for allergies, lab data, specific factors (NPO status)
4. Check daily MAR
5. Perform hand hygiene
6. Start at top of MAR and check each drug against MAR, compare dose.
7. Check medication label three times before administering to client: when retrieve from storage area, when preparing medication, when returning medication to storage area
8. Calculate dosage correctly
9. Automated Dispensing system (PYXIS); controls med supply. Pharm fills w/ meds for 24 hrs, narcotics are in there, tells you what to do, cuts down on missing narcs

At bedside: 2 ID’s, tell them what you’re giving them, educate if needed

VI. SYSTEMS OF MEASUREMENT

1. Metric system
2. Apothecary system
3. Household system
4. Converting units of weight and measure

1. example: MD order (Desired) morphine sulfate gr ¼ IM q4h prn pain. Have morphine 10 mg and 15 mg doses.
2. Conversion: Must Memorize this!! 1 mg=1/60 grain or 60 mg= 1 gr. If 60 mg= 1 gr

then x mg = ¼ gr (0.25)

x= (60 x 0.25)

1

X= 15 mg

3. Converting within metric system; Must memorize these!!

1. 1 gram (g)= 1000 milligram (mg)
2. 1 mg= 1 microgram (mcg)

4. Household conversions

1. 1 tsp= 5 ml
2. 1 Tbsp= 15 ml
3. 30 ml= 1 fluid ounce

5. Converting pounds to kilograms; divide or multiply by 2.2. 2.2 lb= 1 kg.

VII. CALCULATING DOSAGES

1. Ratio formula: D x V = X (D and H must be in same unit of measure)

H

D= dose desired; H= dose on hand; x=dose to be administered; V=vehicle or drug form

1. Example: MD order 500 mg ampicillin sodium; dose on hand is in capsules containing 250 mg.

500 mg= 2 capsules

250 mg

2. To calculate dose when in liquid form, use this formula

1. D x Q = X

H

Example: MD order ampicillin 375 mg when it is supplied as 250 mg/5 ml

375 mg x 5

250 mg so 1.5 x 5 = 7.5 ml

2. Ratio and proportion: H : V :: D : x

C. Fractional Equation: H =D

V x Cross multiple and solve for x.

D. Dimensional analysis:

1. memorize these conversions: 1 g= 1000 mg; 1000mg= 15 gr;

1 g= 15 gr; 1 gr= 60 mg

2. V= V (vehicle) x C (H) x D (desired)

H (on hand) x C (D) x 1 (drug order)

(conversion factor)