This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: FMGE 2019, Subject name: Pharmacology
Antidote for opioid poisoning; 
Select and explain. 
A. Naloxone, B. Pethidine, C. Flumazenil, D. Physostigmine
A: Naloxone
Answer: A: Naloxone 
Explanation: Naloxone is an opioid antagonist given intravenously. It blocks mu, kappa and delta receptors. It is the DOC for opioid toxicity. is given parenterally (ineffective orally) and is a very sho acting drug. Pethidine (Meperidine)- fully agonist at opiod receptors Flumazenil-Flumazenil is specific antidote for benzodiazepines. Physostigmine - it is a lipid soluble anticholinesterase. It is the specific antidote for poisoning with belladonna.