Therapeutics

Question 1

Pharmacodynamics

Answer 1

How medications bind to receptors and signal intended response

Question 2

5 actions of corticosteroids

Answer 2

1) stabilizes cell and lysosomal membranes
2) reduces vascular smooth muscle sensitivity to histamine
3) inhibits histamine release
4) decreases neutrophil migration / adherence
5) decreases production of IL-1

Question 3

Pharmacokinetics

Answer 3

Effect of the body on a medication. Depends on absorption, distribution, bioavailability, metabolism (hepatic), and excretion (renal).

Question 4

4 key topical steroids

Answer 4

UP: Clobetasol proprionate .05% (class I).  Usually limited to 2 weeks unless on palms or soles.  Do not use occlusion (dangerous potency).
HP: Fluocinonide .05% (class II)
MP: Triamcinolone acetonide (class IV)
LP: Hydrocoritoone 1% (class VII)

Question 5

Lotrisone

Answer 5

Combination of clobetasol and clotrimazole (antifungal). Don’t use due to risk of side effects.

Question 6

Where / what are gels used for?

Answer 6

Used for mucosal sites (mouth for pemphigus vulgaris) and face (acne). Contain alcohol, so may burn and dry skin.

Question 7

What is typical dosage for oral steroids?

Answer 7

1 mg / kg / day

Question 8

6 components of a prescription

Answer 8

Full name of medication, potency, vehicle, quantity, directions (freq and site), and refills.

Question 9

Side effects of topical steroids

Answer 9

Acne, rosacea, perioral dermatitis, atrophy (thinning / stretch marks), contact / irritant dermatitis (more often due to the vehicle), infection, cataracts, glaucoma, purpura (bleeding may be due to thinning), rebound, tachyphylaxis (continued application → lower effect, common in psoriasis), or telangiectasias.

Question 10

Tachyphylaxis

Answer 10

Continued application leads to less effect. Common in psoriasis

Question 11

Which vehicles commonly cause side effects?

Answer 11

Formalin, preservatives, lanolin, etc.
Propylene glycol is a humectant and solvent. May cause irritant contact dermatitis.
Formaledhyde may cause allergic contact dermatitis

Question 12

Calcineurin Inhibitors (types, use, population, mechanism, side effects)

Answer 12

Tacrolimus .1% ointment and Pimecrolimus 1% cream.
Topical substitute for MP steroids.
Supposed to be used for atopic dermatitis in age 2+, but often also used for seborrheic dermatitis, contact dermatitis, psoriasis, vitligo, etc.
Act by inhibiting transcription of pro-inflammatory cytokine IL-2.
Do not cause atrophy. Rare burning effects or lymphoma.
Avoid prolonged use. Good alternative when rebound occurs in eyelid dermatitis.

Question 13

When are systemic corticosteroids used? How are they delivered?

Answer 13

Used for severe or systemic diseases, such as pemphigus vulgaris, severe atopic dermatitis, poison ivy, or acne fulminans.
May be delivered orally (po, Prednisone most common), injected (IV, intralesional [IL], or intramuscular [IM]), or inhaled.
Injections are good for diseases w/ fibrosis / thickenings.
IV / oral good for pemphigus vulgaris w/ lots of pain / lesions.

Question 14

Intralesional injections (type, use, side effects)

Answer 14

Include triamcinolone. Good for localized disease such as alopecia areata and keloids. Side effect includes epidermal / dermal atrophy.

Question 15

Side effects of systemic corticosteroids

Answer 15

Osteoporosis (long-term), osteonecrosis (may occur quickly, often in hip), HPA suppression (must taper steroids if used for more than 3 weeks), infection (due to immunosuppresion).

Question 16

Poison Ivy (cause, sxs, tx)

Answer 16

Allergic contact dermatitis → vesicles and bullae.
Reacts w/in 2 days if sensitized.
Wash skin, clothes, and tools. Tx w/ topical or oral corticosteroids for 3 weeks.
Resin takes a long time to get out of the skin.