OTC and Minor Ailments pt 3

1. Q: What is local half-life in topical drug therapy?

the time the drug remains active at the site of absorption

2. Q: How does a long local half life affect dosing frequency?

Allows for daily dosing or reduced dosing frequency due to skin acting as a drug reservoir.

3. Q: How does occlusion affect topical drug absorption?

A: It increases absorption by trapping heat and moisture over the application site.

4. Q: What is the OTC method for wart removal?

A: Cryotherapy and topical salicylic acid (Compound W).

5. Q: Mechanism of salicylic acid in wart treatment?

A: Weakens wart tissue’s adherence to the epidermis, promoting removal.

6. Q: First line OTC treatment for eczema?

Emollients, topical steroids, topical antihistamines.

7. Q: Prescription treatments for eczema?

A: Topical immunosuppressants (tacrolimus, pimecrolimus) and PDE4 inhibitors (crisaborole).

8. Q: How to manage eczema with secondary infection?

A: Add topical antibiotics.

9. Q: Common acne treatments?

A: Benzoyl peroxide, salicylic acid, antimicrobials.

10. Q: Benzoyl peroxide mechanism?

A: Converted to benzoic acid in skin → indirect antimicrobial activity + increased epidermal turnover.

11. Q: Can benzoyl peroxide be combined with antibiotics?

A: Yes, often combined with erythromycin or clindamycin.

12. Q: Retinoic acids examples?

A: Tretinoin, isotretinoin, other Vitamin A derivatives.

13. Q: Retinoic acid mechanism?

A: Increases epidermal turnover, reduces cell cohesion, stabilizes lysosomes, increases RNA polymerase activity, increases PGE₂/cAMP/cGMP.

14. Q: Retinoid common ADRs?

A: Inflammation, peeling, dryness, photosensitivity; acne may worsen first 4–6 weeks.

15. Q: Oral isotretinoin important warnings?

A: Teratogenic (contraception required before and after therapy), can cause skin dryness, lipid changes, IBD, headaches.

16. Q: 1st gen antihistamine role in sleep aids?

A: Anti-wakefulness effect (H1 + muscarinic blockade), common in nighttime cold meds.

17. Q: Melatonin’s origin?

A: Neurohormone derived from tryptophan, released mainly between 9 PM–4 AM.

18. Q: Melatonin receptor actions?

A: MT1 (Gi): promotes sleep; MT2 (Gq): coordinates light–dark cycle.

19. Q: Causes of xerostomia?

A: Anticholinergic drugs, smoking, mouth breathing, dehydration.

20. Q: Xerostomia treatment?

A: Mouthwashes, sprays, lozenges, toothpaste, cholinergic agonists.

21. Q: Canker sore OTC treatments?

A: Benzocaine, corticosteroids, hydrogen peroxide.

22. Q: Severe canker sore treatment?

A: Systemic analgesics, corticosteroids, cauterization (Debacterol).

23. Q: Types of OTC ocular allergy products?

A: Antihistamines, mast cell stabilizers.

24. Q: Example of ocular antimicrobials?

A: Polymyxin B, protein synthesis inhibitors.

25. Q: Ocular vasoconstrictor mechanism?

A: α₁ receptor agonists → reduce redness/swelling.

26. Q: Cause of herpes labialis?

A: HSV-1 virus.

27. Q: Docosanol mechanism?

A: Prevents HSV fusion with host cell.

28. Q: Acyclovir mechanism?

A: Guanine analogue → activated by viral thymidine kinase → inhibits viral DNA polymerase → chain termination.

29. Q: Valacyclovir vs acyclovir?

A: Valacyclovir is an ester prodrug of acyclovir.

30. Q: Famciclovir?

A: Prodrug of penciclovir, guanosine analogue.

31. Q: Common antifungal classes and mechanisms?

A:

• Azoles: inhibit ergosterol synthesis

• Naftifine/Terbinafine/Tolnaftate: inhibit ergosterol synthesis

• Nystatin/Amphotericin B: bind ergosterol, disrupt membrane

• Ciclopirox: binds metal ions, disrupts enzymes.

32. Q: Common antiparasitics for lice/scabies?

A: Permethrin, lindane, crotamiton, sulfur, malathion, tea tree oil.

33. Q: Ivermectin mechanism (antiparasitic)?

A: Binds glutamate-gated Cl⁻ channels → hyperpolarization → paralysis of parasite.

34. Q: Purported antiviral mechanism of ivermectin?

A: Prevents viral protein entry into host cell (requires high concentrations not achievable in humans).

35. Q: High dose ivermectin AEs?

A: Dizziness, confusion, hypotension, seizures, blurred vision, GI upset.

36. Q: Common uncomplicated UTI drugs?

A: TMP-SMX, fluoroquinolones, amoxicillin-clavulanate, cephalosporins, nitrofurantoin, fosfomycin.