Nokea
Which of the following local anesthetics is a thiophene derivative?
- A. Procaine
- B. Ultracaine
- C. Lidocaine
- D. Mepivacaine
Correct Answer: B
Rationale: The correct answer is B: Ultracaine. Ultracaine is a thiophene derivative because it contains a thiophene ring in its chemical structure. Thiophene is a five-membered heterocyclic compound containing sulfur. Procaine (A) is an ester local anesthetic, Lidocaine (C) is an amide local anesthetic, and Mepivacaine (D) is an amide local anesthetic. Therefore, they do not belong to the thiophene derivative class. Ultracaine is the only option that fits the description of being a thiophene derivative.
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Hexamethonium blocks the action of acethylcholine and similar agonists at:
- A. Muscarinic receptor site
- B. Neuromuscular junction
- C. Autonomic ganglia
- D. Axonal transmission
Correct Answer: C
Rationale: Hexamethonium is a ganglionic blocker that acts specifically at the autonomic ganglia. It inhibits the action of acetylcholine at the ganglionic nicotinic receptors, leading to the blockade of autonomic functions. This results in the inhibition of sympathetic and parasympathetic responses. Therefore, the correct answer is C: Autonomic ganglia. Muscarinic receptor site (A) is not directly affected by Hexamethonium. Neuromuscular junction (B) is not the primary site of action for this drug. Axonal transmission (D) is not the specific target of Hexamethonium.
Indicate the antipsychotic drug ,which is a thioxanthene derivative:
- A. Haloperidol
- B. Clozapine
- C. Chlorpromazine
- D. Thiothixene
Correct Answer: D
Rationale: The correct answer is D: Thiothixene. Thiothixene is a thioxanthene derivative due to its chemical structure containing a thioxanthene ring system. Haloperidol, Clozapine, and Chlorpromazine are not thioxanthene derivatives. Haloperidol is a butyrophenone, Clozapine is a dibenzodiazepine, and Chlorpromazine is a phenothiazine. Therefore, the correct choice is D as it is the only antipsychotic drug among the options that belongs to the thioxanthene class based on its chemical structure.
It is undesirable to take alcohol before going outdoors when it extremely cold, but it may be harmless to take some after coming into a warm place from the cold.
- A. TRUE
- B. FALSE
- C. None
- D. All
Correct Answer: A
Rationale: The correct answer is A: TRUE. Alcohol consumption before going outdoors in extremely cold weather can lead to increased risk of hypothermia as it dilates blood vessels and causes heat loss. However, after coming indoors from the cold, having some alcohol may not pose the same risk as the body is already in a warm environment and can regulate its temperature better. Therefore, it is important to avoid alcohol before exposure to cold but may be harmless after being in a warm place. Choices B, C, and D are incorrect because they do not accurately reflect the specific considerations related to alcohol consumption in cold weather.
Which of the following would be an appropriate therapeutic adjustment for the patient with hypermagnesemia, vomiting, and heart failure?
- A. Add potassium supplementation and reduce the digoxin dose
- B. Add atropine and reduce the digoxin dose
- C. Increase the furosemide dose and reduce the digoxin dose
- D. Discontinue digoxin and start losartan
Correct Answer: D
Rationale: Correct Answer: D
Rationale:
1. Hypermagnesemia can exacerbate heart failure.
2. Vomiting may further worsen magnesium levels.
3. Digoxin toxicity is a concern in hypermagnesemia.
4. Discontinuing digoxin is crucial to avoid adverse effects.
5. Starting losartan can help manage heart failure without worsening hypermagnesemia.
Summary:
A: Adding potassium may worsen hypermagnesemia.
B: Atropine is not indicated for hypermagnesemia or heart failure.
C: Increasing furosemide may lead to electrolyte imbalances.
D: Discontinuing digoxin and starting losartan is the appropriate therapeutic adjustment.
Tick the drug that can induce peripheral neuropathy and oral ulceration:
- A. Acyclovire
- B. Zalcitabine
- C. Zidovudine
- D. Saquinavir
Correct Answer: B
Rationale: The correct answer is B: Zalcitabine. Zalcitabine is a nucleoside reverse transcriptase inhibitor commonly associated with peripheral neuropathy and oral ulceration as side effects. These adverse effects are well-documented in clinical studies and are known to be dose-dependent. Zalcitabine can cause damage to peripheral nerves leading to neuropathy and can also irritate the mucous membranes in the mouth causing oral ulceration.
Incorrect Choices:
A: Acyclovir - Acyclovir is an antiviral medication used to treat herpes infections and does not typically cause peripheral neuropathy or oral ulceration.
C: Zidovudine - Zidovudine is also a nucleoside reverse transcriptase inhibitor used in the treatment of HIV, but it is not associated with peripheral neuropathy or oral ulceration.
D: Saquinavir - Saquinavir is a protease inhibitor used to treat HIV and does not commonly induce peripheral neurop