Nalorphine hydrochloride (Nalline Hydrochloride) is approved by the FDA for the treatment of respiratory and circulatory depression in dogs resulting from overdosage of, or unusual sensitivity to, morphine and certain other narcotics. The drug is administered by intravenous, intramuscular, or subcutaneous route. It has analgesic effect. Nalorphine hydrochloride is a narcotic substance with mixed agonist-antagonist properties closely related to morphine. Given alone it produces a broad spectrum of unpleasant effects and it is considered to be clinically obsolete. Nalorphine hydrochloride is a partial potassium agonist and µ-receptor antagonist that exhibits minimal analgesic effects. The efficacy of reversing opioid agonist-induced rspiratory depressio is variable and can exacerbate in some cases.