1. Pharmacology Spring 09 – Unit 2
Carla Hilton, MSN, RN, CNE
Lecture 3
Chapters 28, 77

2. Learning Outcomes
Compare and contrast fundamental concepts related to the use of specific central nervous system drugs, including those used for management of pain, drugs related to the maintenance of bowel function and the management of constipation.
Acquire a working framework for studying drug classifications and nursing implications.

3. Classifications: Opioid (Narcotic) Analgesics, Opioid Antagonists, and Non-opioid Centrally Acting Analgesics
Chapter 28

4. Intro to Opioids Chemical class: Opioid vs opiate
Opiod means they act like an opiate
Opiates are from poppy seeds
Functional class: Narcotic Analagesic
MOA – body peptides (3) enkephalins, endorphins, dynorphins (they produce their effects at these receptor sites)
Opioid receptors - mu, kappa, and delta
Agonist, partial agonist, antagonist
Partial agonists produces low to moderate activation alone, but will block actions of full agonists if given simultaneously
Strong and moderate to strong

5. Table 28-1

6. Opioid Agonists Prototypes MOA / TE Strong: morphine [Duramorph] CII
Moderate to strong: codeine [Paveral] CIII
MOA / TE
Mimics action of endogenous opioid receptors (mu) to produce analgesia and thereby relieve pain
Other effects include drowsiness, mental clouding, anxiety reduction, sense of well-being. CNS Depressant
Oral dose is a lot higher than IV in this case

7. Adverse Effects Resp. depression Others Toxicity
Diminished by “tolerance”
Most common cause of OD death
Others
Constipation, orthostatic hypotension, urinary retention / urgency, cough suppression, biliary colic, emesis, elevated ICP (intracranial pressure), dysphoria, sedation, miosis (small pupils), neurotixicity, immune and hormone suppression with prolonged use
Toxicity
Classic triad (coma, resp. depression, pinpoint pupils)

8. Miosis- tiny little pin point pupils
Mydriasis- with the d in the word, think dilated pupils

9. ADME (Pharmacokinetics) Nursing implications?
Given by several routes
Slowest to fastest
Time-frame for TE varies by mode of administration
If you want the drug now, do IV. We need to know how long it takes these to work
Denatured in liver
Hard to cross blood-brain barrier
Precautions / Contraindications
Decreased resp reserve, pregnancy, head injury, infants (crosses placenta) / elderly, hypotension, liver disease
Interactions
CNS depressants, antihistamines, antihypertensives, MOAIs*, antiemetics, amphetamines, agonist-antagonist, antagonists

10. Dosage – Highly individualized Administration
Table 28-6
Administration
po, IM, IV, SQ, topical, PCA
Oral associated with chronic
Preferably fixed schedule
Site specific – hazards (epidural, effects delayed…)

11. Other Strong Opioids Fentanyl (Sublimaze)
Anesthesia primary use (injectable)
100 X mg potency of morphine
Commonly seen as transdermal
No children under 2 / none for under 18 less than 100 lbs.
Transmucosal (popsicle)
Breakthrough cancer pain
Store carefully
very large amts of drug (can kill!)

12. Hydromorphone [Dilaudid] Methadone Heroin – crosses blood-brain easier
Meperidine [Demerol]
Interacts with several drugs – esp MAOI’s
Toxic metabolite (had problems in the elderly)
Avoid use past 48 hrs and not to exceed 600mg/24hr.
Hydromorphone [Dilaudid]
Methadone
Help people addicted to heroin
Heroin – crosses blood-brain easier

13. Table 28-6 – Dosing for Opioids

14. Moderate to Strong Opioid Agonists
Codeine
Usual dose of 30 mg = about same relief as 325 mg of ASA or Tylenol
Combo meds more effective
Extremely effective cough suppressant at 10 mg dose range
Oxycodone [OxyContin, Percodan] & CR forms
Hydrocodone [Lortab, Norco, Vicodin] CIII
Proproxyphene [Darvon, Darvocet] CIV

15. Special Clinical Concepts r/t Use of Opioids
Pain assessment – including evaluation!
Dosing amt and schedule
Fear of addiction in clinical setting
Avoiding withdrawal – 20 days or more
They can have withdrawal symptoms
Patient controlled anesthesia (PCA)
Morphine: DOC - heart attack (MI)
Meperidine [Demerol]: DOC OB
Doesn’t cross placenta
Avoid opioids in Head Injury…

16. Nursing Implications
Link to ATI pp. 133 (150)

17. Class: Opioid Agonist-Antagonists
Prototype: pentazocine [Talwin]
Others: nalbuphine [Nubain], butorphanol [Stadol]
MOA - act mostly at mu kappa receptor to produce analgesia and relieve pain.
Alone = agonist action
With agonist = can antagonize (blocks mu receptor)
Adverse effects – similar to opioids
ADME (Pharmacokinetics)
Less respiratory depression, low abuse potential
Less effective pain relief
*Can start withdrawal sxms in opioid addiction

18. Class: Opioid Antagonists
Prototype: naloxone [Narcan]
MOA – TE / Use
competes for opiate site and blocks effects of opioid agonists / agonist-antagonists – no significant effect given alone – resulting in REVERSAL of narcotic
ADME
Rebound effect (narcan wears off and they are back under the morphine…)
Adverse effects: acute withdrawal
Dosage/Admin: 04. mg IM, IV, SubQ
Others: naltrexone [ReVia] ETOH/Opioid abuse

19. Non-opioid Centrally Acting Analgesics
Prototype: Tramadol [Ultram]
Others: clonidine [Duraclon] is another centrally acting analgesic – pain / HTN
MOA / TE / Use
Analog of codeine – binds w mu receptor producing analgesia to relieve pain. Also blocks re-uptake of norepinephrine (lots of this in your system)
ADME (Pharmacokinetics)
Minimal potential for dependence or resp depression
Adverse effects
Rare – most common: sedation, dizziness, HA, dry mouth, and constipation
Precautions
Can intensify other CNS dep. – ABSOLUTELY avoid MAOIs

20. Laxatives
Chapter 77

21. Bulk-forming Prototype(s): methylcellulose, psyllium (Metamucil)
Action / Use
Behave like dietary fiber – nonabsorbable – swell to form viscous solution / gel and softening fecal mass and increasing transit.
Temp relief of constipation, diarrhea, irritable bowel, ostomies
Adverse effects
Esophageal & intestinal obstruction if not enough fluid  ? If you don’t take with enough fluid you can obstruct stuff. Builds a brick in the gut that doesn’t move
(If this, then?)

22. Surfactants Prototype: docusate sodium (Colace) Action / Uses ADME
Lower surface tension of stool and softens by facilitating penetration of water into the feces
Act on intestinal wall to inhibit fluid absorption and stimulate secretion of water and electrolytes into the intestinal lumen.
Brings water into the stool and makes it softer
ADME
Full glass of water
Sit upright for 30 min (kind of oil based and you can aspirate the stuff and get pneumonia)
Effectiveness dose related (min 200 mg/day)
Adverse reactions – rare
Dosage: 50 to 500 mg daily ( but usually at least 200 mg a day)

23. Stimulants Typically abused the most
Prototype(s): bisacodyl (Dulcolax), senna (Senekot)
Action / Legitimate Uses
Directly stimulate gut motility, increase secretion of water and ions into intestine, and reduce water and electrolyte absorption.
Uses: Treatment of (1) opioid-induced constipation and (2) slow transit constipation
Dosage: related to formulation administered
Take bisacodyl no sooner than 1 hour after ingesting milk or antacids – do not crush
Adverse reactions
Bowel rupture can occur
If you have gut surgery and your sutures are healing, if you give them this is makes their gut move and can tear open the incision

24. Osmotics Salts Prototype: sodium phosphate (Fleet) and magnesium salts
Action /Uses
Non-absorbable and retains water in the colon
Adverse reaction
Dehydration, diarrhea and loss of water (more with salts than with glycol)
Magnesium can accumulate to toxic levels in renal failure
Sodium can retain fluid – so…. Contraindicated in patients with heart failure HTN and edema
Other: glycol (MiraLax) – fewer side effects / safer

25. Miscellaneous Lactulose (sugar base) Glycerin Suppository
Action / Uses
Poorly absorbed and cannot be digested – by product of breakdown results in osmotic diuresis
Enhances excretion of ammonia in liver failure
SEs – flatulence, cramping
Glycerin Suppository
Polyethylene Glycol-Electrolyte (GoLytely)
Safe in dehydrated or electrolyte sensitive

26. Additional Nursing Implications
High risk patients
Contraindicated in abdominal pain, nausea, cramps, regional enteritis, diverticulitis, ulcerative colitis, acute surgical abdomen, fecal impaction, bowel obstruction.
Abuse
Castor oil (powerful stimulant – avoid at night – not to children)