Pharmokinetics

Question 1

Routes of administration for opiates

Answer 1

Oral
IV
SC
IM
Transdermal patch (fentanyl)
Epidural
Intrathecal
Patient-controlled analgesia (PCA)

Question 2

Opioids get distributed throughout all tissues

Answer 2

Exert their principle analgesic effects after they reach the CNS

Question 3

Where does biotransformation primarily take place?

Answer 3

Liver

Question 4

Where and how does excretion occur?

Answer 4

Excretion of drug metabolite and to a lesser extent the intact drug in the urine via the kidneys

Question 5

Morphine

Answer 5

Morphine-6-Glucuronide (more potent than morphine)

Question 6

Meperidine

Answer 6

Has an active metabolite (normeperidine), which may cause seizures at thigh plasma levels (particularly in elderly patients and pts with impaired renal/hepatic function)
Not for chronic pain

Question 7

Methadone

Answer 7

Very long duration of action

Question 8

Time for peak efficacy
- Morphine

Answer 8

20 minutes

Question 9

Time of the duration of action
- Morphine

Answer 9

4 hours

Question 10

Time for peak efficacy
- Meperidine

Answer 10

15 mins

Question 11

Time of duration of action
- Meperidine

Answer 11

2-4 hours

Question 12

Time of peak efficacy
- Fentanyl

Answer 12

5 mins

Question 13

Time of duration of action
- Fentanyl

Answer 13

15-30 mins

Question 14

Intrathecal and epidural

Answer 14

Use significantly lower doses and provide regional analgesia while decreasing systemic side effects

Question 15

Patient controlled analgesia (PCA pumps)

Answer 15

Allow patients to control opiate injections using a parenteral (I.V.) injection devise

Question 16

Analgesia

Answer 16

They relieve pain both by raising the pain threshold at the SC level and by altering the brain’s perception of pain
Induce sleep in clinical situation when pain is present and sleep is neccessary

Question 17

Opiate analgesics

Answer 17

Represent the mainstay of therapy for the treatment of pts with acute (postoperative) and chronic pain

Question 18

Less drug is need to prevent what?

Answer 18

Recurrence of pain than to relieve it

Question 19

Cough suppression

Answer 19

Dextromethorphan

Question 20

Acute pulmonary edema
- morphine only

Answer 20

Morphine used to decrease anxiety and decrease the perception of shortness of breath

Question 21

Adjunct in anesthesia

Answer 21

Morphine
Fentanyl

Question 22

Treatment of diarrhea

Answer 22

Diphenoxylate and loperamide (OTC)

Question 23

Adverse effects of opiates

Answer 23

Sedation, drowsiness, mental clouding and coma (at toxic doses)
Mitosis (pinpoint pupil)
Euphoria
Constipation (severe)
Urinary retention
Respiratory depression
Nausea
Itching
Addiction liability

Question 24

Adverse effects of opiates
- Miosis (pinpoint pupil)

Answer 24

Important diagnostically bc other causes of coma and respiratory depression produce dilation of pupil

Question 25

Adverse effects of opiates - Euphoria

Answer 25

D/t DA release in the nucleus accumbens

Question 26

Adverse effects of opiates - Constipation (severe)

Answer 26

Stool softeners and laxatives should be initiated early

Question 27

Adverse effects of opiates - Urinary retention

Answer 27

Increase antidiuretic hormone

Question 28

Adverse effects of opiates - Respiratory depression (cardinal toxic effect)

Answer 28

D/t a reduction in the responsiveness of the respiratory center to increase CO2 tension

Question 29

Averse effects of opiates - Itching

Answer 29

D/t opiate Induced histamine release

Question 30

Opiates contraindications

Answer 30

Head trauma Neonates Opiate-induced miosis Respiratory depression

Question 31

Opiates contraindications - Head trauma

Answer 31

Increase intracranial pressure (ICP) from vasodilation and increase CSF volume

Question 32

Opiates contraindications - Neonates

Answer 32

Should not receive morphine bc of their low conjugating capabilities and immaturity of BBB

Question 33

Opiates contraindications - Opiate-induced miosis

Answer 33

Masks the pupillary response used to diagnose concussion

Question 34

Opiates contraindications - Risk of respiratory depression

Answer 34

From heroin is related to its active metabolites (6- acetlymorphine and morphine)

Question 35

Tolerance

Answer 35

Repeated administration of therapeutic doses of the opiates causes gradual loss of effectiveness

Question 36

In order to reproduce the original response

Answer 36

Larger dose is needed

Question 37

Cross-tolerance

Answer 37

Pt tolerant to one opiate drug will also show some degree of tolerance to other opiate agonists

Question 38

Tolerance does not develop to

Answer 38

Mitosis and constipation