Indicate the agent of choice in the emergency therapy of anaphylactic shock:

Correct Answer: D

Rationale: The correct answer is D: Epinephrine. 1. Epinephrine is the drug of choice in anaphylactic shock due to its alpha and beta-adrenergic effects, which help reverse vasodilation, bronchoconstriction, and increased vascular permeability. 2. Methoxamine (A) acts as a selective alpha-1 adrenergic agonist and may worsen the vasodilation in anaphylactic shock. 3. Terbutaline (B) is a beta-2 adrenergic agonist used in asthma but may not be as effective in reversing the systemic effects of anaphylactic shock. 4. Norepinephrine (C) is a potent vasoconstrictor but lacks the beta-adrenergic effects needed to reverse bronchoconstriction and vascular permeability in anaphylactic shock.

Correct Answer: D

Rationale: Step-by-step rationale: 1. Tiagabine inhibits the reuptake of GABA, an inhibitory neurotransmitter, reducing excitatory effects of amino acids. 2. This mechanism helps prevent seizures by increasing GABA levels in the brain. 3. Ethosuximide is used for absence seizures, not related to amino acids. 4. Lamotrigine blocks voltage-gated sodium channels. 5. Diazepam enhances the effects of GABA but does not directly inhibit excitatory amino acids.

Correct Answer: B

Rationale: The correct answer is B: Selegiline. Selegiline is a monoamine oxidase inhibitor used in the treatment of Parkinsonian disorders by increasing dopamine levels in the brain. Phenytoin (A) is an anticonvulsant, not used for Parkinson's. Haloperidol (C) is an antipsychotic, may worsen Parkinson's symptoms. Fluoxetine (D) is an antidepressant, not specific for Parkinson's treatment. Therefore, Selegiline is the most appropriate choice due to its mechanism of action in increasing dopamine levels to alleviate Parkinsonian symptoms.

Correct Answer: B

Rationale: The correct answer is B: Dilatation of the biliary duct. Morphine does not cause dilation of the biliary duct; instead, it can lead to biliary spasm and constriction. Morphine commonly causes constipation by decreasing gut motility, urinary retention by affecting the bladder sphincter, and bronchiolar constriction by acting on the respiratory system. These effects are well-documented pharmacological actions of morphine.

Correct Answer: A

Rationale: The correct answer is A: Carbamazepine. Carbamazepine has a dual mechanism of action, functioning as both an antiseizure medication and an analgesic. It is commonly used to treat neuropathic pain and trigeminal neuralgia. Carbamazepine's analgesic properties stem from its ability to block voltage-gated sodium channels, reducing neuronal excitability and pain transmission. Summary of other choices: B: Ethosuximide - Primarily used for absence seizures, lacks analgesic properties. C: Phenytoin - Effective against various seizure types but does not have significant analgesic effects. D: Clonazepam - A benzodiazepine used as an antiseizure medication, but does not possess analgesic properties.