Dermatologic Pharmacology Flashcards

1
Q

What are the variables of percutaneous absorption? (4)

A

Regional: some places are more absorbent than others (axilla > forearm, etc.).

Concentration gradient

Dosing schedule: long half-life of skin reservoir may allow for once daily dosing.

Vehicles/occlusion

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2
Q

What is a cream made of?

What are some characteristics of application of creams?

They are a better treatment option than ointments for what kind of skin conditions?

A

Half water/half oil with an emulsifier.

They spread easily, are well-absorbed and wash off with water.

They are better for oozing/”wet” skin conditions.

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3
Q

What is an ointment made of?

What are some characteristics of application of ointments?

They are a better treatment option than creams for what kind of skin conditions?

A

20% water and 80% oil.

They feel greasy and are “occlusive”.

They are better for dry skin since they trap moisture.

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4
Q

What provides for more complete absorption of the active ingredient: creams or ointments?

A

Ointments

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5
Q

What is most likely to lead to an allergic reaction: creams or ointments?

A

Ointments

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6
Q

What is the use of the following moisturizer components?

Emollient

Humectants

Horny substance (keratin) softeners

A

Emollient: form an oily layer on top of the skin that traps water in the skin.

Humectants: draws water into the outer layer of the skin.

Horny substance (keratin) softeners: loosens the bonds between the top layer of cells, which helps dead skin fall off and retain water; it makes the skin smoother.

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7
Q

What is the use of the following in sunscreen?

PABA

Benzophenones

Dibenzoylmethanes

A

PABA: active in the UVB range (redness, aging, carcinogenesis).

Benzophenones: active in a wider range than PABA, but is less effective.

Dibenzoylmethanes: active in the UVA range (aging and cancer); useful in drug-induced photosensitivity.

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8
Q

What is the utility of chlorhexidine?

What is its MOA?

A

It is a broad-spectrum antimicrobial agent widely used in homes/hospitals due to general efficacy on skin (and oral mucosa) and low irritability.

Low concentrations affect membrane integrity; high concentrations cause congealing of cytoplasm.

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9
Q

Under what condition is soap and water a better handwashing option than alcohol-based hand disinfection?

A

C. difficile

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10
Q

What is the indication of Becaplermin?

What is its MOA?

What is the black-box warning associated with it?

A

Treatment of chronic diabetic foot ulcers.

It is a PDGF that promotes cell proliferation and angiogenesis.

The use of >3 tubes increases the risk of malignant complications (4x).

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11
Q

Bacitracin

MOA

Coverage

Side-effects

A

MOA: inhibition of bacteria cell wall synthesis.

Coverage: G+ bacteria, anaerobic cocci, Neisseria, Tetanus and Diphtheria.

Side-effects: allergic dermatitis - poorly absorbed through skin, so systemic toxicity is rare.

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12
Q

Neomycin

MOA

Coverage

Side-effects

A

MOA: binds to 30S subunit and inhibits protein synthesis.

Coverage: G- bacteria.

Side-effects: allergic dermatitis - poorly absorbed through skin, so systemic involvement is rare.

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13
Q

Polymyxin B

MOA

Coverage

Side-effects

A

MOA: binds to phosphor-lipids to alter permeability and damage the bacterial cytoplasmic membrane.

Coverage: G- bacteria like Pseudomonas, E. coli, Enterobacter and Klebsiella.

Side-effects: rarely a allergic reaction.

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14
Q

What is the MOA of the antifungal “-azoles”?

What is the indication of the following?
Miconazole
Clotrimazole
Efinaconazole
Ketoconozole
A

Blocks ergosterol synthesis.

Miconazole: vulvovaginal candidaisis.

Clotrimazole: vulvovaginal candidiasis.

Efinaconazole: onychomycosis.

Ketoconozole: dermatophytosis, candidiasis and shampoo/foam for seborrheic dermatitis.

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15
Q

What are the MOAs and indication for the following antifungals?

Ciclopirox
Terbinafine
Tolnaftate
Nystatin
Amphotericin B
A

Ciclopirox: disrupts macromolecular synthesis; dermatophytes (Candida and Malassezia).

Terbinafine: inhibition of squalene epoxidase (needed for ergosterol synthesis); dermatophytes.

Tolnaftate: unknown, but distorts hyphae and stunts mycelial growth; various dermatophytes and malessezia (not Candida).

Nystatin: alters membrane permeability; mucosal and cutaneous Candida.

Amphotericin B: alters membrane permeability; cutaneous Candida.

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16
Q

What is the MOA of Acyclovir?

What is the indication?

A

Synthetic guanine analog with inhibitory activity.

Treatment of recurrent orolabial HSV-1 and HSV-2 ingections in healthy (non-compromised) adults.

17
Q

What is the MOA of Capsaicin?

What is the indication?

A

It binds TRPV1 (a channel in cutaneous nerve fibers), which leads to release of neuropeptides and substance P. It induces lasting desensitization of neurons to a number of stimuli.

Pruritis and chronic pain.

18
Q

What is the MOA of Salicylic Acid?

What is its indication?

A

Inhibition of COX.

Pruritis.

19
Q

What is the drug used for nocturnal pruritis?

A

Mirtazapine

20
Q

What is the drug used for cholestatic pruritis?

A

Sertraline

21
Q

What is Naltrexone used for? (2)

A

Cholestatic pruritis

CKD-associated pruritis

22
Q

What is the drug used for neuropathic pruritis?

A

Gabapentin/Pregabalin

23
Q

What are the 2 drugs used for rosacea?

What is their MOA?

A

Brimonidine: alpha-2 agonist applied as a topical gel.

Oxymetazoline: mixed alpha-1a and alpha-2 agonist applied as a topical cream.

24
Q

What are the MOAs of the following drugs used to treat ectoparasitic infections?

Malathion

Permethrin

Ivermectin

Lindane

A

Malathion: organophosphate cholinesterase inhibitor.

Permethrin: binds Na+ channels and blocks membrane repolarization.

Ivermectin: binds glutamate-gated Cl- channels and hyperpolarizes nerve and muscle cells.

Lindane: disrupts GABAergic transmission in insects (highly toxic, so it is only used after other agents fail).

25
Q

What is the major topical retinoid used for acne vulgaris?

What is the MOA of retinoids?

What are some associated side-effects?

A

Tretinoin

It contributes to the normalization of follicular keratinization and decreased cohesion of eratinocytes. This reduces follicular occlusion.

Local skin irritation, dryness and flaking; sun sensitivity.

26
Q

What 4 topical antibiotics are commonly used to treat acne vulgaris?

A

Benzoyl peroxide
Clindamycin
Erythromycin
Azaleic acid

27
Q

What are the indications for Azaleic Acid?

What is unique about it?

What does it do, in addition to killing acne bacteria?

A

Mild to moderate acne and post-infammatory hyperpigmentation.

It is made of dicarboxylic acid, a white powder in wheat, rye and barley, where it aids in plants’ response to an infection.

It decreases the production of keratin.

28
Q

What is Spironolactone used for?

Which patients is it especially useful?

A

Acne vulgaris.

Adult women with menstrual cycle-related breakouts.

29
Q

What is the only oral retinoid used to treat acne vulgaris?

A

Isotretinoin

30
Q

What is the indication for Apremilast?

What is the MOA?

What is the route of administration?

What are some side-effects?

A

Psoriasis and psoriatic arthritis.

Inhibition of PDE4 and increases cAMP levels. This decreases NO synthase, TNf and IL-23. It increases IL-10.

Oral administration.

Severe N/V/D; HA and psychological symptoms.

31
Q

What is the indication for Ustekinumab?

What is the MOA?

What is the route of administration?

What is a major side-effect?

A

It is a mAb that targets proinflammatory cytokines IL-12 and IL-23. This decreases the activity of many WBCs.

Psoriasis, psoriatic arthritis, Crohn disease.

SubQ infusion.

Increased risk for infection.

32
Q

What is the indication for Secukinumab?

What is the MOA?

What is the route of administration?

What is a major side-effect?

A

It is a mAb that targets the proinflammatory cytokine IL-17A. This decreases the activity of many other signaling molecules.

Psoriasis, psoriatic arthritis, ankylosing spondylitis.

SubQ infusion.

Increased risk for infection.

33
Q

What is the dermatologic indication for 5-fluorouracil?

A

Hypertrophic actinic keratosis

34
Q

What are the MOAs of the following drugs for alopecia?

Minoxidil
Finasteride

A

Minoxidil: opens K+ channels and leads to vasodilation. Promotes hair growth by increasing anagen (growth phase), shortening telogen (rest phase) and enlarging miniaturized follicles.

Finasteride: oral inhibitor of DHT production. It can cause sexual dysfunction.

35
Q

What is first-line therapy for female alopecia?

A

Minoxidil