Mechanism of Action: They exert their effects by binding with opioid receptors.
Adverse Effects:
Miosis
Nausea & vomiting
Drowsiness or sedation
Respiratory depression
Bradycardia in large doses
Itching
Urinary retention
Fentanyl
Mechanism of Action: A potent synthetic opioid agonist with 100 times the analgesic potency of morphine.
Advantages:
No histamine release.
Ability to maintain cardiac stability.
Sufentanil Citrate (Sufenta)
Mechanism of Action: 10 times as potent as fentanyl.
Advantages:
Rapid elimination.
Relatively more rapid recovery as compared with fentanyl.
Alfentanil
Mechanism of Action: Shorter duration of action compared to fentanyl and sufentanil.
Remifentanil (Ultiva)
Mechanism of Action: Ultra short acting and rapidly cleared.
Advantages: Widespread metabolism by blood and tissue esterases.
Morphine
Adverse Effects: May produce hypotension and bronchoconstriction as a consequence of its histamine-releasing action. Morphine may be a poor choice for a patient with bronchial asthma.
Meperidine (Pethidine)
Adverse Effects: Sympathomimetic like effect.
Naloxone
Mechanism of Action: A specific opiate receptor antagonist, binding the receptor.
Adverse Effects:
Reversal of analgesia.
(Tachycardia, hypertension, pulmonary edema, and cardiac dysrhythmias).