L24 - Mercury Drug Interactions

Question 1

What are the types of mercury?

Answer 1

• elemental (pure, liquid or vapour - toxic)
• inorganic (salt e.g. mercury nitrate)
• organic (add carbon e.g. methyl mercury = most toxic)

Question 2

What are the potential routes of exposure to mercury?

Answer 2

• exposure to staff when preparing or working with amalgam (mercury vapour)
• risk to patient of exposure over time due to possibility that mercury vapour is released from the filling

Question 3

Why are some forms of mercury more toxic than others?

Answer 3

• there is low uptake of liquid mercury from the GI tract
• mercury vapour is readily absorbed through the lungs
• mercury vapour diffuses across all tissues in the body but the highest concentrations in the brain and kidney (not much affect just accumulates)
• has more effect on kidneys
• methyl mercury accumulates in the brain
• mercury harmful in the brain because it attacks neurons and destroys brain structures = risk of neurological disorders

Question 4

How can humans be exposed to mercury?

Answer 4

from Atmosphere

• mercury vapour is released naturally from the Earth’s crust into the air
• microorganisms convert mercury vapour into methyl mercury

methyl mercury

• formed by microorganisms
• taken up by aquatic organisms
• bioaccumulation in fish

Question 5

What is a vitamin that is toxic?

Answer 5

• signs of toxicity resembles excess calcium because it enhances Ca2+
  absorption (hypercalcemia + impaired renal function)