Pharmacology Flashcards
How long does an IM drug injection take to take effect in our body?
10 - 20 mins
How long does a SC injection take to work in our bodies?
15 - 30 minutes
Describe what is meant by the “brick and mortar” analogy for the model of the stratum corneum
The bricks are corneocytes, containing keratin filaments.
The mortar are the lamellar structures of intercellular lipids such as cholesterol
How are hydrophobic drugs absorbed in the skin?
The are dissolved in the “mortar” and so can travel through the stratum corneum.
What features of a drug make it suitable for transdermal delivery?
Lipophillic, potent and with a short half life
Describe transdermal drug delivery
The drug is incorporated into an adhesive patch and then applied to the epidermis
What is electroporation?
A short, high voltage pulse which disrupts cell membranes and enhances their permeability allowing the drug to be morse effectively absorbed across.
How do micro needles aid in drug delivery?
They puncture the stratum corneum, allowing less lipophillic drugs to cross the membrane more easily.
How many handprint areas does 1 finger tip unit cover?
2
How many fingertip units is 1g?
2
How many handprint areas are covered by 1g?
4
In what 4 skin conditions are topical steroids widely used?
Psoriasis
Excema
Lichen planus
Keloid scars
Name 4 effects on local corticosteroids.
- Anti inflammatory
- Immunosuppressant
- Vasoconstricting
- Anti proliferation action upon keratinocytes and fibroblasts
Name 5 side effect of topical steroids.
Thinning of the skin Stretch marks Purpura Rosacea Telangactasia Rebound flare Systemic absorption
What is a cream?
Semi solid emulsion of oil in water
What is a lotion?
Liquid suspension in water or alcohol
What is an ointment?
Semisolid grease/oil
What is a gel?
A thickened aqueous lotion
What areas are lotions very good for?
Scalp and other hair bearing areas
What is a paste?
Semi solids with finely powdered material
What are pastes often used for?
Cooling, drying, soothing bandages.
Describe briefly how steroids work
- Steroid hormones are lipophillic and so enter cells by diffusion.
- Within the cell the combine with an intracellular receptor and produce a conformational chang.
- This exposes the DNA binding domain.
- The receptor - steroid complex moves to the nucleus where in binds to steroid response units.
- The transcriptions then switches on/off genes to alter mRNA levels and the rate of synthesis of inflammatory mediator proteins.
Name a mild corticosteroid cream
Hydrocortisone 1%
Name a moderate corticosteroid cream
Modrasone/Clobetasone/Butyrate 0.05%
Name a potent corticosteroid cream
Elocon/Betamethasone/Valerate 0.1%
Name a very potent corticosteroid cream
Clobetasol
Proprionate
0.05%
Why do we try and avoid the use of systemic corticosteroids in skin disease?
There is often a good initial rest but when the steroid are stopped there will be a huge flare up.
In a dry skin disease patient, how much emollient should you prescribe per week?
250 - 500g
When would you use a potassium permanganate rinse?
Acute exudative eczema, pompholyx
What topical antibiotic therapy would you prescribe for acne?
Clindamycin
Erythromycin
Tetracycline
What topical antibiotics would you prescribe for rosacea?
Metronidazole
What treatments would you prescribe for infected eczema?
Combined corticosteroid and antibacterial
What treatment would you prescribe for impetigo?
Fusidic acid, Mupirocin
What treatment would you prescribe for a herpex simplex lesion?
Topical acyclovir
What treatment would you prescribe for herpes zoster (shingles)
IV/Oral aciclovir or valciclovir
What is eczema herpeticum?
A widespread infection with herpes simplex in a patient with previous atopic excema
How would you treat eczema herpeticum?
Oral valcicovir
What kind of treatment do you need in a candida infection?
Anti yeast
What kind of treatment do you need in a ringwork infection?
Anti fungal
What kind of treatment do you need in pityriasis versicolor?
Anti yeast
Given an example of two antipruritics?
Menthol
Capsaicin
Phenol
Coramiton
What topical treatments could you prescribe for viral warts?
Keratolytics to soften the keratin
How would you treat keratin plaques in the scalp?
Keratolytics
How would you treat corns and calluses?
Keratolytics
Give examples of treatments of warts:
Mechanical paring Keratolytics (such as salicylic acid) Formaldehyde Silver nitrate Cryotherapy using liquid nitrogen
How do you treat genital warts?
Podophyllin
How do you treat pruritus ahi?
Phenol/Camphor
List some treatments used in psoriasis
- Emollients
- Coal tar
- Keratolytic
- Topical steroid
- Dithranol
List some treatments used in scalp psoriasis
- Greasy ointments to soften scale
- Tar shampoo
- Steroids in alcohol base
- Vitamin D analogue
