DDI

Question 1

Describe the 2 types of DDI; + 2 Types of ADR

Answer 1

pK - Drug’s movement through the body

• absorption, distribution
• metabolism, excretion

pD - drug’s effect on the body

ADR

• type A - known effects, dose-based
• type B - unknown effects

Question 2

Give ADME areas of pK DDI

name example

Answer 2

Absoprtion

• food
• inorganic ions

Distribution

• plasma protein
• Aspirin displaces Warfarin - bleeding

Metab

• CYP Inducers: rifampicin, St John’s Warts, Anti-epileptics - carbamazepine, phenytoin
• CYP Inhibitors: Azoles, ML, FQ,
• • SSRI too! Fluoxetine, Sertraline, Paroxetine, Escitalopram;
• GRAPEFRUIT JUICE;
• cimetidine;

Question 3

note pD comes off as body response

• Aspirin and Warfarin? Bleeding
• GTN and Sildenafil? Vasodilation and Hypotension

Hence suspect Px taking other drugs, or lifestyle stuff or grapefruit;

Answer 3

ok

Question 4

What are the drugs leading to these Type A ADRs

• Bleeding
• Sedation
• Hypoglycaemic Coma
• Tremors
• Respi Depression
• Hearing loss

Answer 4

• NSAIDs Aspirin, anticoagulants, antiplatlets
• sedation: Gen 1 antihistamine
• Insulin
• Beta agonists eg Salbutamol
• Alcohol; Nicotine; BZD
• Aminoglycosides; Vancomycin; Furosemide; Macrolide

Question 5

Whats a category of type B ADR

Answer 5

HS
I: IgE
- give antihistamine, epinephrine

II: antibody dependent, directed at host cells

III: Ab-Ag complex, leads to vasculities
- penicillin, NSAIDs can;

IV: T Cells

• SJS-TEN
• sulphonamides eg Co-trimoxazole most common cause; sulfamethoxazole