Question

Which of the following drugs has an apparent volume of distribution approximately 6500 litres?

• A. Amoxicillin
• B. Ibuprofen
• C. Chloroquine
• D. Diazepam

Answer 1

The Correct Option is C

To determine which drug has an apparent volume of distribution (V_d) of approximately 6500 litres, let's first understand the concept of 'volume of distribution'.

The apparent volume of distribution is a pharmacokinetic parameter that describes how a drug is distributed throughout the body relative to the concentration of the drug in the blood. This parameter can be impacted by factors such as the drug's lipid solubility, tissue binding, and plasma protein binding.

A large volume of distribution, such as 6500 litres, suggests extensive distribution of the drug into body tissues, beyond the blood. This generally indicates that the drug is highly lipophilic and can distribute into fatty tissues. Let's evaluate each option based on their typical volumes of distribution:

• Amoxicillin: Typically has a moderate volume of distribution since it is primarily distributed in the extracellular fluid and does not extensively bind to tissues.
• Ibuprofen: Known for a relatively low volume of distribution as it is largely bound to plasma proteins and does not distribute widely into tissues.
• Chloroquine: Known for having an extremely high volume of distribution due to its high lipophilicity, allowing it to concentrate extensively in various body tissues, especially the liver, spleen, kidney, and lungs. This corresponds well with the given value of 6500 litres.
• Diazepam: Although it has a relatively high volume of distribution due to its lipophilicity, it is not as high as 6500 litres.

Based on this analysis, the correct answer is Chloroquine, as its pharmacokinetic properties align with a volume of distribution of approximately 6500 litres. This drug is widely distributed throughout the body, which explains its high V_d value.

Thus, the correct answer to the question is Chloroquine.