1 - TOPICAL RETINOIDS Flashcards
Tretinoin (all-trans retinoic acid) is an oxidised form of all-trans retinol and is synthesised endogenously from all-trans retinol after delivery of the compound to basal keratinocytes from the bloodstream
True
Alitretinoin (9-cis retinoic acid) is a naturally occurring endogenous retinoid
True (same as tretinoin and all-trans retinol)
All topical retinoids should be avoided during pregnancy due to risk of teratogenecity
True (although topical absorption of retinoids is generally slight, there is concern when large surface areas are treated)
A pregnancy test is recommended before the use of Tazarotene and Bexarotene (third generation retinoids) in women of child bearing potential, and appropriate birth control measures in place for the duration of treatment
True
All-trans retinol and all-trans retinoic acid are naturally occurring retinoids
True
Cytosolic all-trans retinoic acid-binding protein (CRABP) is predominantly in human skin and may be the determining factor in the bioavailability of retinoids
True (all-trans retinoic acid binds to CRABP)
All-trans retinol is oxidised to all-trans retinoic acid when needed by the cell
True
All-trans retinol is the natural alcohol form of vitamin A that is transported in the blood stream from storage in the liver to the peripheral target tissues bound to the serum transport protein retinol-binding protein
True
All-trans retinol traverses the interstitial spaces in the papillary dermis and is taken up by basal keratinocytes
True
When all-trans retinol is topically applied to the skin, the drug is taken up by the keratinocytes in the outer epidermis and diffuses through the skin as a fat soluble drug
True
Within the keratinocytes, excess all-trans retinol is esterified to long chain fatty acids to form retinyl esters which form lipid droplets (similar to how vitamin A is stored in the liver)
True
Acyl CoA - retinol acyltransferase is an enzyme system that is involved in direct esterification and hydrolysis of retinyl esters important for topically applied all-trans retinol
True
Lecithin - retinol acyltransferase is an enzyme system that is involved in direct esterification and hydrolysis of retinyl esters important for endogenously supplied all-trans retinol
True
All-trans retinoic acid (first generation retinoid Tretinoin) induce genes which are involved in cell proliferation and anti-apoptosis, leading to inhibition of cell growth
True
All-trans retinol and all-trans retinoic acid causes epidermal hyperplasia in thin or atrophic photo damaged epidermis
True
All-trans retinol and all-trans retinoic acid causes normalisation of epidermal thickness in hypertrophic skin
True
Topical application of All-trans retinol and all-trans retinoic acid causes irritation, erythema and desquamation
True
All-trans retinol do not bind to any retinoid receptors
True
All-trans retinoic acid/Tretinoin (first generation retinoid) binds to RAR receptors
True
Alitretinoin (third generation retinoid) binds to all RAR and RXR retinoid receptors
True
Bexarotene (third generation retinoid) binds to RXR retinoid receptors
True
Both Adapalene and Tazarotene (third generation retinoid) bind to RAR retinoid receptors and not RXR retinoid receptors
True (in contrast to third generation Bexarotene which binds to RXR and not RAR retinoid receptors)
Tazarotene (third generation retinoid) is converted to its active metabolite tazarotenic acid
True (Tazarotene is a prodrug)
All-trans retinol, all trans-retinoic acid (both first generation retinoids), Adapalene and Tazarotene (both third generation retinoids) result in comedolysis in acne
True