L3 - Dermatologic Pharmacology Flashcards
What are the variables of cutaneous absorption?
Regional, concentration gradient, dosing schedule and vehicles/occlusion
How does the regional variable affect cutaneous absorption?
E.g. axilla more permeable than the forearm
How does the concentration gradient affect cutaneous absorption?
Increased concentration —> increase drug mass/unit time
How does dosing schedule affect cutaneous absorption?
Long local t1/2 of skin reservoir may permit 1/day dosing
How do the vehicles/occlusion affect cutaneous absorption?
Both can maximize drug penetration
When should you clean your hands?
Before touching a patient Before cleaning/aseptic procedures After body fluid exposure/risk After touching patient After touching pt surroundings
Describe some basic hand hygiene
Should wash for 15-30 seconds with plain soap for hand washing (but this doesn’t reliably prevent microbial transmission)
Frequent hand washing may cause skin damage and irritation
Describe alcohol based hand disinfection
Easier/faster than soap and water
Rapidly effective against gram positive, gram negative and viral pathogens
Not effective against C diff (so must use soap and water)
How do gloves provide protection from contaminated material?
Provide protective barrier from contaminated material reducing chance of transfer of infection from patient to healthcare worker and vice versa
But still need to wash hands since gloves often have small defects or tears that are un apparent + hands become contaminated during removal of gloves
Describe healing by first intention
Inflammatory phase (debridement) Proliferative phase (granulation) —> (epithelialization) Remodeling phase (apoptosis of excess cells, re-alignment/cross linking of collagen)
Describe healing by second intention
Larger scab (clot) Inflammation more intense because there is more necrotic debris, exudate and fibrin to remove Larger amounts of granulation tissue - larger defect Involves wound contraction
In primary closure of surgical wounds in high risk pts poor glycemic control is significantly associated with what?
Worse outcomes
Postoperative hyperglycemia is frequent after what kind of surgery?
Elective colorectal surgery in non diabetic pts
Even a single post operative elevated glucose value is adversely associated with morbidity and mortality
What can cause a generalized itchy rash?
Ring worm (tinea corporus) or nail infection (onchomycosis, tinea unguium)
What can cause an itchy rash on the scalp?
Sebhorreic dermatitis or head lice
What can cause an itchy rash of the back?
Grover disease (transient acantholytic dermatosis)
What can cause an itchy rash on the hands?
Pomphoylx (eczema -> itchy blisters on hands/feet)
Hand dermatitis
What can cause an itchy rash of the genitals?
Vulvovaginal candida, pubic lice, lichen sclerosis, jock itch (tinea cruris)
What can cause an itchy rash on the legs?
Gravitational eczema
What can cause an itchy rash on the feet?
Athletes foot (Tinea pedis)
What can cause neuropathic localized pruritus of the face?
Trigeminal trophic syndrome
What can cause neuropathic localized pruritus of the arm?
Brachioradial pruritus
What can cause neuropathic localized pruritus of the back?
Brachioradial pruritus
What can cause neuropathic localized pruritus of the vulva?
Pruritus vulvae
What can cause neuropathic localized pruritus of the anus?
Pruritus ani
What can cause neuropathic localized pruritus of the any dermatome?
Herpes zoster (shingles) during recovery phase
What are two topical vasoconstrictors used to resolve the redness in rosacea?
Brimonidine and oxymetazoline
What is brimonidine?
Alpha2 adrenergic agonist applied as a topical gel
Vasoconstricts by stimulation post synaptic vascular alpha2 receptors
What is oxymetaxoline?
Mixed alpha1A/alpha2 adrenergic agonist vasoconstrictor applied as a topical cream
What agents can be used to relieve redness in the eyes through vasoconstriction?
Naphazoline, tetrahydrozoline, phenylephrine, and oxymetazoline
Eye drops are all adrenergic receptor agonists
What are common agents used for killing of ectoparasites?
Malathion, permethrin, ivermectin, lindane
What is malathion?
Topical agent
Organophosphate cholinesterase inhibitor
What is permethrin?
Topical agent
Binds to insect Na channels and blocks membrane repolarization
What is ivermectin?
Administered orally
Binds to glutamate gated Cl channels in invertebrates
Hyperpolarizes the nerve and muscle cells
What is lindane?
Topical agent
Toxicity causes it to be used only after other agents fail
Disrupts GABAergic transmission in insects
Which topical therapies are the initial choice for mild to moderate psoriasis?
Emollients and corticosteroids
Which topical therapies used to treat psoriasis have an unclear mechanism but reduce keratinocytes proliferation?
Topical vitamin D analogs such as calcipotriene and calcitriol
What is tar?
Ancient remedy for psoriasis
Mechanism unknown but has some anti proliferative effects
Largely displaced by less messy/odorous choices but can be a useful adjunct
Which topical psoriasis therapy has an unknown mechanism but has anti inflammatory effects?
Anthralin
slows something
What are some other topical therapies for psoriasis?
Tazarotene (retinoid gel)
Calcineurin inhibitors (tacrolimus, pimecrolimus)
Salt water bath (e.g. Dead Sea)
What are some drugs that cause skin discoloration?
Amiodarone, daunorubicin, gold, methotrexate, psoralens and 5-fluorouracil (patchy dispigmentation)
Minocycline (generalized dyspigmentation)
Iron, silver, hydroquinone and hydroxyurea (discoloration at site of administration)
Bleomycin (flagellate pigmentation)
Which drugs can cause discoloration of the eyes?
Rifampin turns tears and urine orangish rash
Prostaglandins (e.g. latanoprost) increase iris pigmentation
Minocycline turns sclera blue
How are alcohols used as disinfectants?
Used for antisepsis, to disinfect surfaces and preservation
However they are flammable
Cannot be used to sterilize
How can aldehydes be used as a disinfectant?
Used to disinfectant surfaces, sterilize medical instruments, and for preservation
Highly toxic
What is an example of a biguanides?
Chlorhexidine digluconate
Used for antisepsis, disinfect surfaces and preservation
Why should triclosan (a type of bisphenol) be avoided?
Commonly used in antiseptic soaps but has toxic effects on the skin and also it accumulates in the environment
What kind of a disinfectant is household bleach?
Halogen releasing
Can be used for antisepsis and disinfection purposes
Iodine solutions can cause irritation and staining
What type of disinfectant is hydrogen peroxide?
Peroxygen
Used for disinfection, anti sepsis and sterilization
Peracetic acid is potent and not used for preservation
What are phenolics used for?
Anti sepsis and preservation
Phenol is no longer used as it is corrosive and carcinogenic
But a number of derivatives are used
What are quaternary ammonium salts used for?
Disinfection and preservation
Found in Fantastik cleaner
Why is it not a good idea to administer amphotericin B intravenously?
Serious systemic infections due to adverse effects
Fever/chills, cramps, muscle pain, arrthymia, change in urination, nausea and vomiting
“Amphoterrible” when administered IV
Describe the use of topical steroids and their potency
Use low potency on face, genitals and skin folds
Elsewhere generally start high potency to gain control and titrate downward for maintenance
