Locals: Lipid Vs Pka Vs Protein Binding

Question 1

High Lipid Solubility

Answer 1

• Increased Potency (better membrane penetration)
• Increased Duration (stored in fat, slow release)
• Increased Systemic toxicity risk (accumulates in CNS/heart)

Mnemonic: Lipo = Long-lasting, but Likely Toxic

Question 2

Low Lipid Solubility

Answer 2

Low/Decreased Potency
Low/Decreased Duration
Low/Decreased Toxicity risk

Mnemonic: Low Lipo = Less Powerful & Safer

Question 3

High pka (>7.4)

Answer 3

Low Non-ionized drug = Low Membrane penetration = Slower onset

Mnemonic: High pKa = Hangs Around Before Working

Question 4

Low pKa (~7.4)

Answer 4

High Non-ionized drug = High Membrane penetration = Faster onset

Mnemonic: Low pKa = Lightning Fast

Question 5

High Protein Binding

Answer 5

• High/Increased Duration (acts as reservoir)
• Decreased/Low Free drug = Decreased/Low Toxicity

Mnemonic: Bound = Buffer

Question 6

Low Protein Binding

Answer 6

• Decreased/Low Duration (acts as reservoir)
• High/Increased Free drug = High/Increased Toxicity

Mnemonic: Free = Frisky (Toxic!)

Question 7

What is lipophilicity?

Answer 7

Lipophilicity = how the drug moves through fat and tissues

Lipophilic drugs are the people who jump into the ocean (fatty tissue) and swim everywhere—deep, strong, but may drown (toxic!).

Question 8

What is plasma protein binding?

Answer 8

Plasma protein binding = how much drug is stuck in the bloodstream, unable to act

Protein-bound drugs are the ones tied to beach chairs (plasma proteins). They can’t go anywhere until they get unbound. Only the free ones can party (act on tissues or cause toxicity).