It is capable of blocking a placebo pain-lowering response, if the placebo is administered together with a hidden or blind injection of naloxone. Other studies have found that placebo alone can activate the bodys μ-opioid endorphin system, delivering pain relief by the same receptor mechanism as morphine.Naloxone should be used with caution in people with cardiovascular disease as well as those that are currently taking medications that could have adverse effects on the cardiovascular system such as causing low blood pressure, fluid accumulation in the lungs (pulmonary edema), and abnormal heart rhythms. There have been reports of abrupt reversals with opioid antagonists leading to pulmonary edema and ventricular fibrillation. Hypersensitivities
Naloxone preparations may contain methylparaben and propylparaben and are inappropriate for use by people with a paraben hypersensitivity. If a person is sensitive to nalmefene or naltrexone, naloxone should be used with caution as these three medications are structurally similar. Cross-sensitivity among these drugs is unknown. Preservative-free preparations are available for those with paraben hypersensitivities. Pharmacology
Pharmacodynamics
Naloxone is a lipophilic compound that acts as a non-selective and competitive opioid receptor antagonist. The pharmacologically active isomer of naloxone is (−)-naloxone. Naloxones binding affinity is highest for the μ-opioid receptor (MOR), then the δ-opioid receptor (DOR), and lowest for the κ-opioid receptor (KOR); naloxone has negligible affinity for the nociceptin receptor.If naloxone is administered in the absence of concomitant opioid use, no functional pharmacological activity occurs, except the inability of the body to combat pain naturally.
Few reach middle age. Diagnosis  must be made within few days or even hours to prevent death. References


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