Pain drugs

Question 1

Opioid drugs

Answer 1

pain control, cough suppression (Codeine), control of diarrhea (Diphenoxylate)

Question 2

Opioid receptors

Answer 2

G-protein coupled receptors _ opioid receptors (u, k, delta); distributed in neurons of CNS, periphery, smooth muscle

Question 3

Opioid distribution

Answer 3

rapidly throughout body, but lower in brain because of blood brain barrier; can cross placenta easily

Question 4

Opioid excretion

Answer 4

liver converts morphine into morphine-6-glucuronide and morphine-3-glucuronide; metabolites have significant pharmacological effects

Question 5

Morphine

Answer 5

opium powder has 10-12% morphine, 0.5-1.0% codeine

Question 6

Opioid pharmacological effects

Answer 6

analgesia, euphoria, tranquility, sedation, mood change, mental clouding, respiratory depression, cough suppression, nausea vomiting, irregular cycles, reduced sex drive, hypotension, initial decreased body temperature, muscle relaxation and rigidity, consitpation, urinary retention, pupil constriction (miosis)

Question 7

Tolerance

Answer 7

adaptations that require the use of greater doses of drug over time (couple weeks); little/no tolerance: miosis, constipation; opioid rotation

Question 8

Physical dependence

Answer 8

adaptations in the body that produce a withdrawal syndrome, with symptoms opposite of pharmacoloical effects of opioids; starts within few hours of last does, peakst at ~12 hrs, subsides spontaneously, usually within a week

Question 9

Addiction

Answer 9

physical and psychological craving for a drug due to action on reward centers, dependence on state for euphoria and indifference, or to avoid withdrawal; does not occur in everyone unlike tolerance and physical dependence

Question 10

Codeine

Answer 10

orally effective, used for cough and relief of dull, continuous pain; weak analgesic (1/10th potency of morphine) and has few side effects

Question 11

Heroin

Answer 11

Diacetylmorphine, most lipophilic of all opioids; hydrolyzed to morphine in the brain; 3-4x more potent than morphine, withdrawal symptoms are more intense -> frequent overdose

Question 12

Oxycodone

Answer 12

chemical modification of codeine, similar to morphine pharmacology; with apsirin (Percodan), with acetaminophen (Percoset); Oxcycotin longer lasting ~12 hrs, abused by crushing and injection

Question 13

Fentanyl (Sublimaze; china white)

Answer 13

used only for severe pain, surgery (supplmements general anesthesia); 80-100x more potent than morphine, highly lipid soluble, onset = 5 mins, duration 0.5-1 h

Question 14

Methadone

Answer 14

similar pharmacological effects as morphine; single dose = 6 hrs but repeated doses cause it to act longer 16-20 hrs; methadone as a replacement for heroin addiction

Question 15

Diphenoxylate (Lomotil)

Answer 15

used only as antidarrheal; Lomotil is a combination of diphenoxylate and atrophine

Question 16

Tramadol

Answer 16

synthetic codeine analog used for moderate to moderately severe pain; weak u receptor agonist and acts NOR and serotonin uptake inhbitor

Question 17

Nalbuphine

Answer 17

used for moderate to severe pain, may have ceiling to respiratory depression

Question 18

Buprenorphine (Buprenex)

Answer 18

less euphoria and respiratory depression than heroin or methadone; injected, onset 2-3 mins, duration 3-6 hrs; ‘methadone’ opiate replacement therapy

Question 19

Naloxone

Answer 19

perfect antagonist, no action or cross-antagonism; i.v. administration for treating acute opioid intoxication or overdose; 1-2 onset, 1-4 hr duration -> must reinject or give naltrexone

Question 20

Naltrexone

Answer 20

oral opioid antagonist; long lasting duration (48-72 hrs)

Question 21

To prevent orally absorbed opioids from being crushed and injected

Answer 21

co-package oral agonist with naloxone