opioids and etc

Question 1

Opioid Receptors

Answer 1

— Mu receptors: Analgesia, respiratory depression,
euphoria, sedation, and physical dependence
— Kappa receptors: Analgesia and sedation; kappa activation may underlie psychotomimetic effects seen with certain opioids
— Delta receptors

Question 2

Agonist-Antagonist Opioids

Answer 2

— Pentazocine, nalbuphine, butorphanol, and buprenorphine
— When administered alone, produce analgesia
— If administered with a pure opioid agonist, can
antagonize analgesia caused by the pure agonist

Question 3

Morphine

Answer 3

— Source
— Seedpod of the poppy plant
— Overview of pharmacologic actions — Pain relief
— Drowsiness
— Mental clouding
— Anxiety reduction— Overview of pharmacologic actions — Respiratory depression
— Constipation
— Urinary retention
— Orthostatic hypotension — Emesis
— Miosis
— Cough suppression
— Biliary colic
— Tolerance and physical dependence
— Tolerance to respiratory depression can develop
— Increased depression with concurrent use of other drugs that have CNS depressant actions (e.g., alcohol, barbiturates, and benzodiazepines)
— Can compromise patients with impaired pulmonary function
— Asthma, emphysema, kyphoscoliosis, chronic cor pulmonale, and extreme
obesity

Constipation
Treatment includes physical activity, increased intake of fiber and fluids, stimulant laxatives, stool softeners, and polyethylene glycol

Orthostatic hypotension
— Morphine-like drugs lower blood pressure by blunting the baroreceptor reflex and by dilating peripheral arterioles and veins

Urinary retention and hesitancy

— Emesis
— Promotes nausea and vomiting through the direct stimulation of the chemoreceptor trigger zone of the medulla

Ø Euphoria/dysphoria
— Euphoria: An exaggerated sense of well-being caused by the activation of mu receptors
— Dysphoria: A sense of anxiety and unease
— Dysphoria is uncommon among patients in pain, but it may occur when morphine is taken in the absence of pain

— Physical dependence
— Abstinence syndrome with abrupt discontinuation
— About 10 hours after last dose, the initial reaction occurs and
includes yawning, rhinorrhea, and sweating

— Drug interactions
— CNS depressants
— Anticholinergic drugs
— Hypotensive drugs
— Monoamine oxidase inhibitors — Agonist-antagonist opioids
— Opioid antagonists
— Other interactions

— Toxicity
— Clinical manifestations
— Classic triad — Coma
— Respiratory depression — Pinpoint pupils
— Treatment
— Ventilatory support
— Antagonist: Naloxone [Narcan]
— General guidelines
— Monitor vital signs before giving
— Give on a fixed schedule

— Morphine/naltrexone [Embeda]: Designed to discourage
morphine abuse

Question 4

— Fentanyl

Answer 4

— 100 times the potency

of morphine

Question 5

— Codeine

Answer 5

— Actions and uses
— 10% converts to morphine in liver — Pain and cough suppression
— Preparations, dosage, and administration
— Usually oral (formulated alone or with aspirin or
acetaminophen)
— 30 mg produces same effect as 325 mg of acetaminophen

Question 6

— Oxycodone

Answer 6

— Analgesic actions equivalent to those of codeine
— Long-acting analgesics
— Immediate-release
— Controlled-release [OxyContin]
— Abuse: Crushes and snorts or injects medication
— 2010 OP formulation much harder to crush and does not dissolve into an injectable solution to decrease risk of abuse

Question 7

— Hydrocodone

Answer 7

— Most widely prescribed drug in the United States
— Combined with aspirin, acetaminophen, or ibuprofen
— Tapentadol
— Analgesic effects equivalent to oxycodone
— Causes less constipation than traditional medications

Question 8

Naloxone

Answer 8

Reversal of opioid overdose
— Drug of choice with pure opioid agonist overdose — Titrated cautiously with physical dependence
— Reversal of postoperative opioid effects
— Titrated to achieve adequate ventilation and to maintain pain
relief
— Reversal of neonatal respiratory depression
— Opioids given during labor and delivery may cause respiratory depression in neonate

Question 9

— Methylnaltrexone and Naloxegol

Answer 9

— Selective opioid antagonist
— Treatment of opioid-induced constipation in late-stage disease for patients receiving constant opioids
— Block mu opioid receptors in the gastrointestinal tract

Question 10

— Alvimopan

Answer 10

— Peripherally acting mu opioid antagonist developed
— Counteracts the adverse effects of opioids on bowel function
— Does not reduce opioid-mediated analgesia: Limited ability to cross the blood-brain barrier
— Short-term therapy of opioid-induced ileus after partial small or large bowel resection with primary anastomosis

Question 11

Naltrexone

Answer 11

— Pure opioid antagonist
— Opioid and alcohol abuse
— Opioid abuse: Prevents euphoria if the abuser takes an opioid
— Candidates for treatment must be rendered opioid free before naltrexone is started
— Does not prevent craving for opioids

Question 12

Clonidine

Answer 12

— Treatment of hypertension and relief of severe pain
— Mechanism of pain relief
— Alpha2-adrenergic agonist
— Analgesic use
— Used in combination with opioid analgesics
— Adverse effects
— Cardiovascular: Severe hypotension, rebound hypertension, and bradycardia

Question 13

Ziconotide

Answer 13

— Mechanism of action
— Selective antagonist at N-type voltage-sensitive calcium
channels on neurons
— Blocks calcium channels on primary nociceptive afferent neurons in dorsal horn of the spinal cord

Question 14

Dexmedetomidine

Answer 14

— Selective alpha2-adrenergic agonist
— Acts in the CNS to cause sedation and analgesia
— Uses
— Short-term sedation in critically ill patients who are initially
intubated and undergoing mechanical ventilation
— Sedation for nonintubated patients before or during surgical and other procedures

— Adverse effects — Hypotension — Bradycardia
— Drug interactions
— Preparations, dosage, and administration

Question 15

Agonist-Antagonist Opioids

Answer 15

— Pentazocine
— Actions and uses
— Preparations, dosage, and administration
— Butorphanol
— Buprenorphine
— 7-day patch: Butrans
— Sublingual film: Suboxone