7. Over the Counter Drugs

Question 1

What is an OTC drug?

Answer 1

• No prescription required
• Safe for use without (health professional) supervision when used as indicated
  
  • Simple directions of use
    
    • Ease of self-management
  • Large TI/margin of safety —> means chances of overdosing are relatively low
  • Few drug interactions
    –> also for why its cheaper

Question 2

What are the OTC drug regulations?

Answer 2

• Still must pass clinical trails and receive government approval!
  
  • Canada: Health Canada, Health Products and Food Branch (HPFB)
  • United States: Food and Drug Administration(FDA)
• Same process and standards as prescription drugs
  meaning were initially improved for sale and use
• Many drugs start as prescription (meaning were initially improved for sale and use), and become OTC after further data proves them safe for self-management
  
  • ex. ibuprofen, loratidine, ranitidine, omeprazole

Question 3

**can refer to slide 5 for whole diagram of OTC drugs

Answer 3

other side!

Question 4

What are antihistamines?

Answer 4

• Antagonists of histamine receptors (any drug that block histamines = antihistamines)
  
  • Competitive/Reversible antagonists
  • used in treatment of allergies

Question 5

What are Histamines and its receptor subtypes?

Answer 5

• Important autacoid molecule
  
  • Complex physiology (means its often produced in different areas of the body)
  • Neurotransmitter and non-neuronal cellular mediator
  • Local release due to various stimuli bc doesnt stay long in the body
• Four receptor subtypes (all GPCRs*), the most important of which are
  
  • H1 – Smooth muscle, endothelial cells, central nervous system (literally everywhere in the body but the stomach)
  • H2 – Gastric mucosa - aka stomach
• mass cells release histamine into extracellular fluid

*we are only focused on H1 and H2
*CPCR = G protein coupled receptor

Question 6

What does H1 do?

Answer 6

• H1- mediated
  
  • Stimulates sensory nerves
    
    • (If they find neurons, they can activate them)
    • Pain and itching
  • Vasodilation
    
    • (If it finds its way into the cardiovasular system, it can bind to smooth muscle vessel,
    • Arterioles & pre-capillary sphincters
• Endothelial cell separation
  
  • histamines can cause little gaps and have fluid leak out into extracellular space –> swelling during allergy season
• Direct stimulation of heart
  
  • Tachycardia: increase heart rate
• Bronchoconstriction
  
  • laboured breathing (mild)
  • anaphylactic shock

Question 7

What does H2 do?

Answer 7

• H2 modulates gastric acid release from the cells that line the stomach into the lumen of the stomach
• acid has low acidic/pH environment to help with digestion.
• H -mediated
  
  • parietal cells that line the stomach are the point of entry for acid into the lumen of the stomach. H2 receptors that are on those cells are activated by histamines being released
    -Stimulation of gastric acid release from parietal cells
  • Released from adjacent enterochromaffin-like (ECL) cells
    
    • Constitutive level
    • “Food”-induced increased level
    • ECL cells is always releasing a bit of histamine that go bind to H2 receptors on parietal cells —> releasing acid through proton pump = low pH