1. Drugs for Muscles and Joint Disease and Pain
Chapter 13
Drugs for Muscles and Joint Disease and Pain

2. Muscles and Joints
Bones of the skeletal system provide framework of the body
Are connected at joints
Joint: place of union or junction between 2 or more bones
Skeletal muscles: provide movement at joints, contractile tissues

3. Anatomy of a Joint

4. Bones, Muscles, and Tendon for Movement at Elbow Joint

5. Three Types of Muscle

6. Muscle Relaxants Skeletal muscle contractions voluntarily
Neurotransmitter acetylcholine (Ach)
binds with receptors on muscle cell membrane
calcium is released, causing a contraction
Relaxation occurs when ACh is broken down by acetylcholinesterase

7. Muscle Relaxants Medications
Acts on motor neurons or at neuromuscular junction
Block normal muscle function by
Blocking release of ACh
Preventing destruction of Ach
Preventing ACh from reaching receptors

8. Dispensing Issues of Muscle Relaxants
To avoid drug interactions, drug history needed before administering
Technician often obtains drug history
Sedative properties cause patient to relax, reducing reflex impulse conduction

9. Side Effects of Muscle Relaxants
Sedation
Reduced mental alertness
Reduced motor abilities
GI upset
Avoid alcohol when taking these drugs

10. carisoprodol (Soma) Skeletal muscle relaxant subject to abuse
Scheduled substance in many states
Causes drowsiness and dizziness
Toxicity risk increases with alcohol or other CNS depressants

11. cyclobenzapine (Flexeril)
Centrally acting skeletal muscle relaxant related to TCAs
Treats muscle spasms associated with acute musculoskeletal conditions
Onset of action is within 1 hour
Not to be used more than 2 to 3 weeks

12. Discussion
Most muscle relaxants are not controlled substances, so why are they highly abused? They are abused due to the relaxing feeling that patients have from taking them.

13. Inflammation and Swelling
Analgesics used to relieve pain
Nonnarcotic analgesic used for mild-to-moderate pain, inflammation, and fever
Two types of pain
Somatic: dull, throbbing pain from skin, muscle, or bone
Visceral: sharp, stabbing pain from organs

14. Inflammation Pain pathway in tissue injury
PGs can cause inflammation, tissue damage, and fever
Nonnarcotic analgesics interrupt pathway, inhibiting enzyme to synthesize PGs
Relieves inflammation and pain
Reduces fever

15. Pain Pathway in Tissue Injury

16. NSAIDs Properties of nonsteroidal anti-inflammatory drugs (NSAIDs)
Analgesic (pain relieving)
Anti-inflammatory
Antipyretic (fever reducing)
Prototype NSAID is aspirin

17. Therapeutic Uses of NSAIDs
Inflammation and pain of arthritis and rheumatism
Headache
Menstrual cramps
Backache
Muscle aches
Flu
Fever
Gouty arthritis

18. Mechanism of Action of NSAIDs
Inhibit PG synthesis in inflamed tissues
Prevents sensitization of pain receptors
Generally act peripherally, not centrally like other pain killers

19. The GI System and NSAIDs
Primary side effect is GI upset
One in five chronic NSAID users develop some type of GI gastropathy
Many patients need to take a proton pump inhibitor with NSAIDs

20. Side Effects of NSAIDs Nausea Abdominal cramps Heartburn Ulcers
Indigestion
Kidney damage
Acute renal failure
Fluid retention
Hypertension
Hyperkalemia
Liver abnormalities
Bone marrow depression
Tinnitus and others

21. Interactions with NSAIDs
Other NSAIDs including aspirin
Beta blockers
Cyclosporine
Digoxin
Diuretics
Methotrexate
Oral hypoglycemics
Warfarin

22. Tips for NSAID Users Take with food
Use antacids or proton pump inhibitor
Do not use gastric irritants (ETOH)
Stop NSAID before any surgical procedure
Use the lowest possible dose
Be aware of side effects
Take sufficient fluids
If sensitive to aspirin, avoid NSAIDs

23. Precautions of NSAIDs
Concurrent use with multiple NSAIDs, including aspirin, should be discouraged
Could lead to additive or synergistic toxicity
Use of NSAIDs and opiates may be synergistic
Considerable patient-to-patient variability to different NSAIDs

24. ibuprofen (Advil, Motrin)
Controls fever well
Can be alternated with aspirin
OTC: 200 mg tablet, caplet, or capsule (solids)
Rx: 400 mg, 600 mg, and 800 mg solids (tablets)

25. naproxen (Naprosyn) Least risky NSAID for cardiovascular events
Used in lowest effective dose for least amount of time

26. COX-2 Inhibitors 2 enzymes critical in inflammation process
Cyclooxygenase-1 (COX-1): extensive role in body, including protecting GI lining
Cyclooxygenase-2 (COX-2): pain, inflammation
Drugs only block the COX-2 enzyme which is induced during inflammation

27. Therapeutic Uses of COX-2 Inhibitors
Rheumatoid arthritis
Osteoarthritis
Menstrual cramps
Acute pain

28. celecoxib (Celebrex) First COX-2 inhibitor to be approved
GI upset is primary side effect
Only COX-2 inhibitor on the market
All others recalled by FDA

29. Dispensing Issues of celecoxib (Celebrex)
Technician—attach the label “Take with Food”
Beware of cross-sensitivity with sulfonamides
May increase cardiovascular risk
Look-alike and sound-alike
Celebrex
Cerebyx (anticonvulsant)

30. allopurinol (Zyloprim)
Used to prevent gout attacks
Liver function should be monitored
Used with caution with diuretics