Morphine sulfate (5 mg i.v.): can be repeated after 5 min.
*To produce analgesia.
*To ↓ stress of the patient → ↓ sympathetic discharge and heart work.
*Morphine causes venodilatation → ↓ venous return and ↓ cardiac work.
Morphine is usually given s.c. except in AMI (5 mg i.v.).
Morphine is contraindicated in cases of MI involving the inferior wall of the heart (inferior MI) because in this case, the patient has bradycardia and morphine causes vagal stimulation → aggravation of bradycardia.
So,What another opioid analgesic could be used in inferior MI? Meperidine because it has atropine-like action → counteract bradycardia.