In the case of a Heparin overdose, which antidote would you give?

Correct Answer: D

Rationale: In the case of a Heparin overdose, the antidote of choice is Protamine sulfate. Heparin is a commonly used anticoagulant medication, and if an overdose occurs leading to excessive bleeding, Protamine sulfate can be administered to reverse the effects of Heparin by neutralizing its anticoagulant activity. It forms a complex with Heparin, rendering it inactive and helping to slow down or stop the bleeding. Naloxone is used as an antidote for opioid overdose, Ibutilide is used for arrhythmias, and Methylphenidate is a central nervous system stimulant commonly used to treat ADHD. But these antidotes are not appropriate for reversing the effects of a Heparin overdose.

Correct Answer: A

Rationale: Warfarin is an anticoagulant medication that works by inhibiting the action of vitamin K, reducing blood clotting. In cases of Warfarin overdose or excessive anticoagulation resulting in bleeding complications, the antidote is vitamin K. Vitamin K helps the liver produce clotting factors, which can counteract the effects of Warfarin and restore normal blood clotting. Other options such as Naloxone, Digibind, and Flumazenil are antidotes used for specific situations like opioid overdose, digoxin toxicity, and benzodiazepine overdose, respectively, and are not relevant for Warfarin antidote.

Correct Answer: B

Rationale: The main difference between ester group local anesthetics and amide group local anesthetics lies in the way they are metabolized in the body. Esters are metabolized in the plasma by the enzyme pseudocholinesterase, while amides are metabolized in the liver. Pseudocholinesterase hydrolyzes esters into inactive metabolites, which are then excreted mainly by the kidneys. On the other hand, amides undergo hepatic metabolism by the cytochrome P450 enzyme system before being excreted by the kidneys. This key metabolic difference between esters and amides impacts their pharmacokinetics, including onset of action, duration of effect, and potential for allergic reactions.

Correct Answer: D

Rationale: Terfenadine is a second-generation antihistamine, but it is not an H1 receptor antagonist like the other options listed. Terfenadine was once used for the treatment of allergic conditions, but it is known for its potential to cause cardiac side effects due to its interaction with other medications and prolongation of the QT interval. Consequently, terfenadine has been largely replaced by newer, safer antihistamines. The rest of the options listed (chlorpheniramine, promethazine, cimetidine, and diphenhydramine) are all H1 receptor antagonists commonly used to block the action of histamine and relieve symptoms of allergies.

Correct Answer: C

Rationale: Aspirin causes gastrointestinal upset because it inhibits both cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) enzymes. These enzymes are responsible for the production of prostaglandins, which are important in protecting the stomach lining. Inhibition of COX-1 reduces the production of protective prostaglandins that help maintain the integrity of the stomach lining, leading to irritation and potential damage, which can manifest as gastrointestinal upset. This is why patients taking aspirin may experience gastrointestinal side effects such as stomach pain, ulcers, or bleeding.