WITH SOLUTIONS GRADED A+
✔✔Lotion/solution/Foam - ✔✔can be water or alcohol based, little residue
✔✔Liposomes and microgel - ✔✔can enhance penetration and decrease irritation
✔✔Best vehicle for use with chronic inflammation w/ xerosis, scaling, and lichenification
- ✔✔lubricating vehicles (creams/ointments)
✔✔Best vehicle for scalp or hairy areas - ✔✔most convenient for application are
tinctures, lotions, gels, foams, and aerosols
✔✔Considerations in dermatologic Pharmacology - ✔✔• Absorption pathways of intact
vs. diseased skin
• Effect of chemistry of the drug on penetration
• Effect of the vehicle on penetration
• Amount of drug that penetrates the skin
• Any host and/or genetic factors that impact drug function in the skin
• Proper dosage & frequency of application
• Patient age - Children have > ratio of surface area to mass than adults → same amt.
of drug can result in greater systemic exposure
✔✔Preferable characteristics of topical drugs - ✔✔-low molecular mass
-adequate solubility in oil and water
Except for very small particles, water-soluble ions and polar molecules do not penetrate
intact stratum corneum
✔✔General Guidelines for Dosage of Topical Therapy - ✔✔Dosage: amount of topical
medication sufficient to cover affected body surfaces in repeated applications
• General rule is approx. 30gm required to cover entire body surface
✔✔Common local cutaneous reactions to topical agents include - ✔✔irritation - non-
allergic - most common localized reaction.
photoirritation - non-allergic - phototoxicity
allergic contact dermatitis - allergic - hypersensitivity
photallergic contact dermatitis - allergic - hypersensitivity
immunologic contact urticarial - allergic - IgE-mediated hypersensitivity (can cause
anaphylaxis)
non-immunologic contact urticarial - non-allergic- most common contact urticaria
✔✔Hydration - ✔✔drug absorption increased w/ hydration
✔✔Methods of hydration - ✔✔occlusion with impermeable film
,application of lipophilic occlusive vehicles such as ointments
soaking dry skin before occlusion
✔✔Patient Variables - Skin-barrier function - ✔✔intact vs dermatologic disease
✔✔Patient Variables - Age - ✔✔• Children- have a greater ratio of surface area to mass
than adults and absorb up to 3x as much as adults-→ same amt. of topical drug results
in a greater systemic dose
• Geriatric skin- thinner and more absorbent
• Pregnant and lactating women-be especially cautious of drug absorption and
contraindications
✔✔Combination Anti-infective & Corticosteroids - ✔✔• Some topical anti-infectives
contain corticosteroids in addition to antibiotics
• Combination therapy may be superior to corticosteroid monotherapy in secondarily
infected dermatoses colonized with strep, staph, or both
✔✔Antibiotic-corticosteroid combinations are useful in treating - ✔✔diaper dermatitis
otitis externa
infected eczema
✔✔Bacitracin and Gramicidin - ✔✔• Active against *gram-positive organisms* (strep,
staph) and most anaerobic cocci (neisseriae, tetanus, diphtheria bacilli)
• Bacitracin ointment - alone or combined w/ neomycin, polymyxin B, or both
• Microbial resistance can develop
• Allergic dermatitis common- urticaria rare
• Minimal systemic absorption
✔✔Mupirocin (Bactroban) - ✔✔• Most gram-positive aerobic bacteria (including MRSA)
sensitive to mupirocin
• Effective in tx of impetigo caused by S aureus and group A -hemolytic strep
• Intranasal mupirocin ointment for eliminating nasal carriage of S aureus - associated
with irritation
• Mupirocin not well absorbed systemically
✔✔Polymyxin B - ✔✔• Effective against *gram-negative organisms* (Pseudomonas,
Ecoli, enterobacter, klebsiella
• May be compounded in a solution or ointment base
• Serum concentrations usually undetectable w/ topical application→ caution in denuded
skin or open wounds
• *Black box warning-neurotoxicity, nephrotoxicity*
• Hypersensitivity to topical polymyxin B sulfate uncommon
✔✔Topical Neomycin and Gentamicin - ✔✔• Aminoglycoside antibiotics active against
gram-negative organisms
,• Gentamicin w/ greater activity against P aeruginosa than neomycin & more active
against staph & group A β-hemolytic strep
Neomycin
frequently causes allergic contact dermatitis
• Rarely detectable in serum
• Available in numerous topical formulations, alone and in combination w/ polymyxin,
bacitracin, and others
Gentamicin
Serum concentrations possible-esp, in renal insuff/failure
• Possible nephrotoxicity, neurotoxicity, & ototoxicity
• Available as ointment or cream
• Avoid widespread topical use in hospitals d/t occurrence of gentamicin resistant
organisms
✔✔Acne Treatment Considerations - ✔✔• Severity
• Lesions-
non-inflammatory or inflammatory
• Treatment preferences
• Cost implications
Patient Age
• Skin type
• Adherence
• Response to previous therapy
• Presence of scarring
• Psychologic effects
• Family history of persistent acne
✔✔Salicylic Acid - ✔✔• MOA-keratolytic, may be antibacterial & antiinflammatory
• Mild irritant, can cause skin peeling, burning, erythema
• Available OTC for mild acne (Aveeno Clear Complexion)
• Used as a peeling agent
• Stronger formulations → wart removal
✔✔Antimicrobials in Acne - 4 antibiotics - ✔✔*Clindamycin, erythromycin,
metronidazole, sulfacetamide*
*Effectiveness less than systemic tx w/ same antibiotic*
Topical Therapy: typically in mild to moderate cases of inflammatory acne
✔✔Topical Clindamycin - ✔✔• Activity against Propionibacterium acnes - thought to be
mechanism of its beneficial effect in acne therapy
• Approximately 10% of an applied dose is absorbed
• Hydroalcoholic vehicle and foam formulations can cause skin drying/ irritation
, • Water-based gel and lotion formulations well tolerated w/ Clindamycin is also available
in fixed-combination topical gels with benzoyl peroxide (BenzaClin, Duac), and w/
tretinoin (Ziana)
✔✔Topical Metronidazole - ✔✔• Used topically in tx of rosacea
• MOA unknown - thought to inhibit Demodex brevis; May act as an anti-inflammatory
agent w/ direct effect on neutrophil cellular function
• Adverse local effects- water-based gel formulation (MetroGel) -dryness, burning,
stinging
• Less drying -creams/lotions, may be better tolerated
• Caution near the eyes to r/t excessive tearing
• Oral metronidazole shown to be a carcinogen in susceptible rodent species, use in
pregnancy not recommended unless clearly needed*
✔✔Topical Sodium Sulfacetamide - ✔✔Tx of acne vulgaris & acne rosacea
• 10% lotion (Klaron), 10% wash (Ovace), & in combination w/ sulfur for the treatment of
acne vulgaris and acne rosacea
• MOA thought to be inhibition of P acnes
• Approx. 4% of topical absorbed percutaneously
*→ contraindicated in pts w/ known allergy/hypersensitivity to sulfonamides*
✔✔Topical Dapsone - ✔✔5% Gel for acne vulgaris
• MOA-unknown
• Bacteriostatic
• Common ADE-dryness, redness, oiliness skin peeling
• No serious ADE w/ topical use
• Minimal absorption-May use during pregnancy
• Avoid during lactation
✔✔Other Acne Preparations include - ✔✔• Retinoic acid
• Isotretinoin
• Benzoyl peroxide
• Azelaic acid
• Acne (Azelex)
• Acne rosacea (Finacea)
• Brimonidine (Mirvaso)
✔✔Retinoic Acid - Topical - ✔✔Tretinoin
• Acid form of vitamin A,
• Oral and topical formulations
• MOA-decreased cohesion between epidermal cells and increased epidermal cell
turnover
• Causes slight erythema with mild peeling → can cause too much irritation
• avoid contact:corners of nose, eyes, mouth, and mucous membranes
• Avoid in pregnancy-esp. 1st trimester
• Initially (4-6 weeks Tx) > may seem worse ......