16 Questions
Which of the following organs is considered a highly perfused organ for drug distribution?
Lung
What is the distribution equilibrium of mepacrine in the liver compared to plasma?
21,000/1
Which barrier is responsible for restricting the distribution of drugs to the brain?
Blood-brain barrier
What factor affects the cellular distribution of phenobarbital?
pH of extracellular fluid
What is the effect of abnormal cellular proliferation on the vascular supply to cancer tissue?
Decreases vascular supply
What property allows lipid soluble drugs to permeate through the lipid membrane for cellular distribution?
Small size of molecules
Which factor affects the distribution of drugs to the CNS by making capillaries in the brain less permeable to water-soluble substances?
Cellular lipid sheath (BBB)
Which drug can penetrate the blood-brain barrier rapidly due to its high partition coefficient?
Thiopental
Why has giving dopamine as a replacement therapy for Parkinsonism failed?
It is water-soluble and cannot penetrate BBB
Why are tetracycline and penicillin not suitable for prophylaxis in meningitis?
They are highly ionized in the blood
What affects placental distribution of drugs?
pH of maternal and fetal blood
Which drugs must be taken into consideration during pregnancy due to their potential effects on the fetus?
Alcohol and nicotine
What is the main plasma protein involved in drug binding process and which type of drugs does it bind more with?
Albumin - acidic drugs
What does plasma protein binding do that influences the duration of action of drugs?
Increases half-life and duration of action
Which drug has a high plasma protein binding of 98%?
Dicoumarol (Bishydroxycoumarin)
What type of drugs does globulin mainly bind with?
Basic drugs
Explore the concept of drug distribution in the field of physiology. Learn about the reversible transfer of drugs between blood and extravascular fluids and tissues, as well as the equilibrium of mepacrine in different organs. Gain insights into the perfusion of various organs and tissues.
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