Naloxone (N-allyl oxomorphone) and newer drugs like nalmexone, naltrexone, nalmefene, and nalbuphine belong to naloxone group. These drugs have practically no agonist action on any of the receptors or their subtypes.
But these drugs completely reverse the action of all the drugs, pure, partial, agonist-antagonists at µ, K, σ, δ and other receptors including analgesia, respiratory depression. But they themselves stimulate nausea and vomiting.
The cardiovascular effects due to cardiovascular stimulation are seen—tachycardia, hypertension, pulmonary oedema and cardiac arrythmias.
The dosage of naloxone include the preparation is 0.4 mg/mL and usually that is the loading dose for normal adult and can be repeated every five minutes in supplements of 50 µg. For neonatal use, 20 µg is available and entire dose will be needed as the initial dose.