Intro to Derm Pharm Flashcards
What is the fxn of skin?
- Protection
- Thermal regulation
- Immune responsiveness
- Biochemical synthesis
- Sensory detection
What does skin represent for pharm access? What are the variables determining response?
- Complex series of diffusion barriers
- Variables determining response:
- Drug penetration
- Concentration gradient
- Dosing schedule
- Vehicles and occlusion
What are the routes of drug absorption for skin?
- Intact stratum corneum
- Sweat ducts
- Sebaceous follicles
What are the steps involved in percutaneous absorption?
- Steps involved in percutaneous absorption:
- Concentration gradient established
- Partition coefficient
- Diffusion coefficient
- Rate of absorption:
- J = Cveh · Km · D/x
What are the signs of chronic inflammation? Which are the appropriate vehicles?
Chronic inflammation with xerosis, scaling, lichenification:
creams and ointments
What are the signs of acute inflammation? What are the appropriate vehicles?
Acute inflammation with oozing, vesiculation, and crusting:
tinctures, wet dressings, and lotions
List different vehicles from drying to lubricating.
tinctures <
wet dressings <
lotions <
gels <
aerosols <
powders <
pastes <
creams <
ointments
What drugs are delivered transdermally? What are their indications?
fentanyl (Duragesic) - pain
lidocaine (Lidoderm) - neuralgia pain
Ethinyl estradiol/norelgestromin (Ortho-Evra) - contraceptive
nitroglycerine (Transderm Nitro) - Angina
scopolamine (Transderm-Scop) - motion sickness
- A 10 yo male presents to the urgent care clinic with his father following a mountain bike accident. His knee and elbow have been scraped.
- PE: mildly abraded areas over knee and elbow covered in dirt and rocks.
- His father would like to know if Neosporin (bacitracin, neomycin, polymyxin B) would be effective?
- What are the mechanisms of action of the individual components of Neosporin (bacitracin, neomycin, polymyxin B)?
A.Increases permeability of cell wall
B.Inhibits cell wall synthesis
C.Inhibits 30S ribosomal subunit
Bacitracin - Gram + (streptococci, pneumococci, staphylococci), anaerobic cocci (Peptostreptococcus), Neisseriae, Tetanus bacillis, Diptheria bacili
- inhibits cell wall synthesis
Polymyxin B - Gram negative organsims (P. aeruginoas, E. coli, Enterobacter, Klebsiella)
- increases permeability of cell wall
Neomycin - Gram negative organisms including E. coli, Enterobacter, Klebsiella, Proteus
- aminoglycoside, inhibits 30s ribosome
- A 5 yo female is brought to urgent care by her mother after returning from kindergarten with red sores around her mouth.
- You suspect non-bullous impetigo and would like to suggest a topical antibiotic ointment.
- Which two topical antimicrobials cover group A β-hemolytic streptococci and S. aureus (including MRSA)?
A.Mupirocin
B.Neomycin
C.Polymyxin B
D.Retapamulin
muciprocin - DOC for impetigo
retapamulin is good too
Group A beta hemolytic strep = Strep pyogenes
What is the treatment approach to non-bullous impetigo?
- 5 yo female with non-bullous impetigo
- General treatment approach:
- Non-bullous impetigo – topical therapy with mupirocin or retapamulin for 5 days
- More extensive forms of impetigo and bullous forms – oral antimicrobials for 7 days
What are hte benefits of topical therapy for non-bullous impetigo?
- Benefits of topical therapy:
- Fewer side effects
- Lower risk of bacterial resistance
•Bacitracin-neomycin-polymyxin B has some activity against impetigo causing organisms – why can’t we use this combination?
d
What are the general requirements for topical AB in acne? What are the available options?
- Avoid systemic exposure and achieve high follicular concentrations
- Less effective than systemic administration of the same antibiotic
- Available options:
- Clindamycin
- Erythromycin
- Metronidazole
- Sodium sulfacetamide
Are ABs used as monotherapy for acne?
- Not used as monotherapy (bacterial resistance)!
- Give with benzoyl peroxide or retinoids
- A 35 yo male construction worker presents to his PCP with complaints of intense itching of both feet throughout the day.
- PE: webs spaces white, macerated, cracked
- Workup consistent with dermatophyte infection
- What topical therapeutic options are available?
Topical Preps include:
azoles
ciclopirox olamine
allyamines
butenafine
tolnaftate
What is the MOA and uses for azoles? What are the drugs?
- Azoles – clotrimazole, miconazole
- MOA: inhibits synthesis of ergosterol (inhibits lanosterol 14-α-demethylase)
- Uses: tinea corporis (ring worm), tinea pedis (athlete’s foot), tinea cruris (jock itch), tinea versicolor, and cutaneous candidiasis, such as vaginal yeast infections, infections of the skin, diaper rash, and thrush (candidiasis of the oral mucosa and tongue, and sometimes the palate, gingivae, and floor of the mouth)
What is the MOA and uses for ciclopirox olamine?
- MOA: inhibits uptake of precursors of macromolecule synthesis
- Uses: topical dermatomycosis, candidiasis, tinea versicolor, mild-to-moderate onychomycosis
What are the MOA and uses for allylamines? What are the drugs?
- Allylamines – terbinafine and naftifine
- MOA: inhibits squalene epoxidase
- Uses: tinea corporis, tinea cruris, and tinea pedis
What is the MOA and uses for tolnaftate?
- MOA: unknown
- Uses: tinea pedis, tinea cruris, and tinea corporis
What are some antifungal agents? How do they work?
Topical Preparations
- Nystatin/amphotericin B
- MOA: binds ergosterol in fungal cell membrane altering permeability
- Nystatin limited to topical cutaneous and mucosal uses - Thrush
- Amphotericin B broad antifungal spectrum but rarely used topically
- Cumulative organ toxicity “ampho-terrible”
What are the types of oral preparationts of antifungal agents?
Oral Preparations
- Azoles
- Griseofulvin
- Terbinafine
What are the uses and ADRs associated with oral azoles?
- Azoles
- Uses: vaginal, urinary, oropharyngeal, or esophageal candida infections
- Systemic yeast infections more common: type 1 diabetes, leukemia, AIDS
- Drug-drug interactions!
What is the MOA and uses for griseofulvin?
- Griseofulvin
- MOA: inhibits fungal cell mitosis at metaphase
- Uses: dermatophyte infections but not Candida
- Induces CYP enzymes