This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Central Nervous system, Subject name: Pharmacology
All of the following are true about opioids except? 
Select and explain. 
A. Naloxone is sho acting, B. Naltrexone is used to lower craving in alcoholics, C. Nalmefene can be used for opioid poisoning, D. Nalmefene is shoer acting than naloxone
D: Nalmefene is shoer acting than naloxone
Answer: D: Nalmefene is shoer acting than naloxone 
Explanation: Nalmefene is a derivative of Naltrexone and is orally effective and longer acting. Naltrexone, is a medication primarily used to manage alcohol or opioid dependence. An opioid-dependent person should not receive naltrexone before detoxification. It is taken by mouth or by injection into a muscle. Effects begin within 30 minutes. All the other statements are true. Ref: KD Tripathi 8th ed.