1. Pain Medications and Muscle Relaxers ESAT 4001 Pharmacology in Athletic Training

2. Pain and Analgesics Pain. Good, or bad? Pain usually prevents individual from continuing a harmful activity Masking pain. Good, or bad? Types of pain medications

3. Non-Narcotic Analgesics Salicylates –Aspirin –Peripheral inhibition of prostaglandin synthesis = analgesic effect –Antipyretic effect as a result of inhibition of prostaglandin synthesis in the hypothalamus Possibly increases blood flow to skin ~ causing sweating ~ dissipation of heat

4. Non-Narcotic Analgesics Ibuprofen –Analgesic effect w/in 2-4 hr Acetaminophen –Tylenol –Weak prostaglandin inhibitor –Useful in treatment of mild-moderate pain –Can be supplemented by strong narcotic agent to increase potency for treating severe pain

5. Narcotic Analgesics Codeine, morphine Exogenous opioids more powerful than endogenous opioids Opioid receptors Common side effects – drowsiness, dizziness, blurred vision, nausea, and vomiting ADDICTION

6. Anesthetics and Skeletal Muscle Relaxants

7. Neuromuscular-Blocking Agents True skeletal muscle relaxants Decrease the response to the neurotransmitter Ach at the neuromuscular junction Also either depolarizes membrane (causes muscle twitch) or do not (no twitch)

8. Depolarizing Drugs Succinylcholine – only depolarizing NM-blocking agent used in US Effects are similar to ACh –Longer effect than ACh

9. How Succinylcholine Works Not metabolized effectively at synapse –Membranes remain depolarized and unresponsive to stimulus –Flaccid paralysis –Continued exposure causes decreased depolarization ~ membrane repolarizes –Membrane cannot be depolarized by ACh as long as succinylcholine is present Desensitization of membrane by succinylcholine

10. Non-depolarizing Drugs Tubocurarine Work in one of 2 ways –Low dose – attaches to nicotinic receptor, prevents ACh binding Works as long as dose is sufficient; if more Ach is made available it will over power drug –High dose – blocks ion channels of the synapse Further weakens nerve transmission, makes ACh more inactive

11. Cardiovascular & Other Effects of Neuromuscular-Blocking Agents

12. Local Anesthetics Work only on area of administration Locals can block all nerves in area –Sensory and motor functions blocked Surgical concern, will block both Continued athletic participation……

13. Action of Local Anesthetics Preferentially block small fibers due to shorter pathways –Small-diameter fibers are first to fail to conduct –Anesthesia of large, myelinated nerve requires that 3 successive nodes be blocked The thicker the nerve ~ the farther apart the nodes = greater resistance to blockade Myelinated tend to be blocked before unmyelinated of same diameter –Exception to above – nerve bundles

14. Administration of Local Anesthetics Topical application Small-nerve injection Major nerve trunk injection Spinal cord infiltration Sympathetic fiber block

15. Types of Local Anesthetics

16. Central-Acting Muscle Relaxants Soma, flexeril, valium, robaxin, norgesic Actions –Mechanism is not well understood; overall effect is sedation –All are general CNS depressant No evidence that they can selectively relax skeletal muscle Side effects –Drowsiness, nausea, light-headedness, vertigo, ataxia, & headache