Analgesia - APAP, NSAID, Muscle Relaxant

Question 1

NSAID Families

Answer 1

1. Carboxylic Acids
2. Propionic Acids
3. Acetic Acid Derivatives
4. Enolic Acids
5. Fenamates
6. Napthylkanones

Paxton: start with Ibuprofen or Naproxen –> enolic acids –> acetic acid

Question 2

NSAIDs MOA?

Answer 2

Inhibit COX1 +/- COX2

1 - regulates most normal cellular processes
2 - expressed during inflammation

Reversibly bind platelets, except ASA

Question 3

What conditions are NSAIDs indicated?

Answer 3

1. Analgesia
2. Antipyretic
3. Dysmenorrhea
4. Anti-inflammatory (rheum conditions)

Question 4

Who are NSAIDs contraindicated in?

Answer 4

Recent CABG

Pregnancy

Question 5

NSAIDs are pregnancy category ___ because?

Answer 5

Category C

• early: miscarriage
• later: fetal renal dysfunction, premature closure of PDA

Question 6

General side effects/ risks of NSAIDs?

Answer 6

1. GI, CV, Renal
2. Caution w/HTN, HF, CKD, asthma
3. May precipitate asthma and anaphylactoid reaction in ASA-sensitive pt (not IgE-mediated)

Question 7

Describe the GI side effects related to NSAIDs?

Answer 7

• Dyspepsia/gastritis & ulceration/perforation*
• INC r/o GI bleed w/anti-plt, EtOH, steroids
• may exacerbate IBD

Question 8

Describe the CV side effects related to NSAIDs?

Answer 8

• r/o thrombosis [BBW INC r/o CV events]
• d/c ALL (except ASA) in AMI pt
• caution w/warfarin
• reversible plt dysfunction –> INC bleeding time
• may interfere w/anti-plt effect of ASA (try other analgesics first)

Question 9

Describe the renal side effects related to NSAIDs?

Answer 9

• DEC efficacy of diuretics (loops/thiazides & ACE/ARB) –> AKI risk
• INC [Li]
• nephrotoxicity: fluid retention, AIN, ATN

Question 10

Who must you avoid NSAIDs in?

Answer 10

Pt with high GI and CV risk

Question 11

Your elderly patient is on diuretics and ACE/ARB. You need to start him on NSAIDs now too. What must you monitor?

Answer 11

Monitor renal function and serum K within 7 days of starting the NSAID

Question 12

Recognize Carboxylic Acids

Answer 12

1. ASA*
2. Salsalate
3. Diflunisal
4. Choline Mag Trisalicylate

Question 13

Recognize Propionic Acids

Answer 13

1. Ibuprofen*
2. Naproxen*
3. Fenoprofen
4. Ketoprofen
5. Flurbiprofen
6. Oxaprozin

Question 14

Recognize Acetic Acid Derivatives

Answer 14

1. Indomethacin*
2. Diclofenac*
3. Ketorolac*
4. Sulindac
5. Etodolac
6. Tolmetin

Question 15

Recognize Enolic Acids

Answer 15

1. Piroxicam (better CV, worse GI)

2. Meloxicam (worse CV, better GI)

Question 16

Which NSAID is safest for breastfeeding women? It also has low GI toxicity.

Answer 16

Ibuprofen

Question 17

Which NSAID is safest in terms of CV toxicity?

Answer 17

Naproxen

Question 18

Which propionic acid has more GI toxicity, ibuprofen or naproxen?

Answer 18

Naproxen

Question 19

Which acetic acid is used for PDA closure? Give it to the baby, but don’t give to pregnant women!

Answer 19

Indomethacin (IV for PDA closure)

Question 20

What are two side effects of Indomethacin?

Answer 20

• worst GI toxicity

- high r/o thrombosis

Question 21

Acetaminophen max dose

Answer 21

• 1,000 mg/dose

- 4g/day

Question 22

Acetaminophen indications

Answer 22

• Antipyresis

- Mild-mod pain –> IV APAP more robust that PO

Question 23

Acetaminophen MOA

Answer 23

• Not clear
• Analgesia: Inhibit NO pathway mediated by certain NTs
• Antipyretic: inhibits endogenous pyrogens

Question 24

Acetaminophen ADRs

Answer 24

-Hepatotoxicity (inc glutathione–> acetylimidoquinone)

• > 3 drinks/day + APAP
• > 4g/day (50% unintentional, iatrogenic)
• Additive effect if given with =/> 1 hepatotoxic med (INH, etc)

Question 25

Acetaminophen Hepatotox tx

Answer 25

Acetylcysteine- given within 8-10 hr of OD

Question 26

Acetaminophen and Pregnancy

Answer 26

- Category C | - Occasional use is fine for mild-mod pain

Question 27

Prescribing APAP

Answer 27

-put max tabs/day in sig to help keep patients from going over 4g/day

Question 28

Cyclobrenzapine

Answer 28

- MOA: near identical to amitriptyline - Indications: SHORT-TERM (2-3 wks) muscle spasms--> has most evidence for efficacy - Interactions: death with CNS depressants, don't give 14d of MAOI, seizure reported with tramadol - CI in pts with arrhythmia, AMI, HF - ADRs: sedation, dizziness, xerostomia quinidine-like effect (QT-prolongation)**

Question 29

Carisoprodol

Answer 29

- MOA: unknown - Indication: don't use according to MISTER Paxton - Schedule IV drug - Interactions: additive sedation with CNS depressants - ADRs: dizziness/sedation, transient quadriplegia, temporary loss of vision**

Question 30

Baclofen

Answer 30

- Indications: SC injury/MS | - Withdrawal sx or worsening spasticity if not tapered over 2 wks

Question 31

Dantrolene

Answer 31

- Spasticity in BS or SC injury - Also used for malignant hyperthermia (IV) ADR: dose-dependent hepatotoxicity

Question 32

You should avoid this acetic acid derivative at all costs, due to toxicity, especially with CV events. What are the other side effects?

Answer 32

Diclofenac CV events; greatest r/o thrombosis ``` Increased HTX (dili drug) Increased GI tox ```

Question 33

Your patient requires a pain med. Which potent NSAID could you give IV. You must limit IV/IM to less than 5 days otherwise there is increased risk of ____.

Answer 33

Ketorolac AKI > 5d

Question 34

3 drugs to minimize GI side effects of NSAIDs. Which is preferred?

Answer 34

1. Misoprostol 2. H2Ras (famotidine) 3. PPIs (omeprazole)**

Question 35

Misoprostol is a progesterone analogue used to prevent gastric ulcers. Know these other two things:

Answer 35

- SE: diarrhea | - Cat X (abortion)

Question 36

What's the 1 Cox-2 selective NSAID still on market?

Answer 36

Celecoxib

Question 37

What's the main use of Cox-2 inhibitors?

Answer 37

Anti-inflammatory for rheum AE: - less GI toxicity - nephrotoxicity

Question 38

Which drugs are used for MS, SC injury?

Answer 38

Antispastics - baclofen - dantrolene

Question 39

Which muscle relaxants are used for other msk conditions?

Answer 39

Antispasmodics - cyclobenzaprine* - carisoprodol* - metaxalone - methocarbamol - chlorzoxazone - tizanidine - orphenadrine