DƯỢC LÍ Goodman & Gilman's The Pharmacological Basis of Therapeutics 12th, 2010

Table 65–4
Topical Retinoids
RECEPTOR PREGNANCY
DRUG FORMULATION SPECIFICITY CATEGORY STRUCTURE IRRITANCY
Tretinoin 0.02%, 0.025%, 0.05%, RAR-, RAR-, C
H
H
O
++
H
0.1% cream RAR-
O
0.01%, 0.025%,
0.04% gel
0.05%, 0.1% solution
H H H H
Tazarotene 0.05%, 0.1% cream RAR-, RAR-, X ++++
O
0.05%, 0.01% gel RAR-
S
C C
N
O
Adapalene 0.1%, 0.3% cream RAR-, RAR- C
O
+
0.1%, 0.3% gel
H
O
0.1% solution
O
Alitretinoin 0.1% gel RAR-, RAR-, D
H
H H H
++
O
H
RAR-
Bexarotene 1% gel RXR-, RXR-, X +++
RXR-
H
H
O
O H
O
topical retinoids. Within the dermis, this is believed to
result from inhibition of activator protein-1 (AP-1), a
transcription factor composed of c-Jun and c-Fos that
normally activates synthesis of matrix metalloproteinases
in response to UV irradiation (Kang and
Voorhees, 2008). In the epidermis, retinoids induce epidermal
hyperplasia in atrophic skin and reduce keratinocyte
atypia (Sami and Harper, 2007).
Toxicity and Monitoring. Adverse effects of all topical
retinoids include erythema, desquamation, burning, and
stinging (Table 65–4). These effects often decrease with
time and are lessened by concomitant use of emollients.
Patients also may experience photosensitivity reactions
because of enhanced reactivity to UV radiation and
have a significant risk for severe sunburn. Although
there is little systemic absorption of topical retinoids
and no alteration in plasma vitamin A levels with their
use, it is recommended that exposure to topical
retinoids be avoided during pregnancy.
Tretinoin
Topical tretinoin (all-trans-retinoic acid) is photolabile and thus
should be applied once nightly for acne and photoaging. Benzoyl
peroxide also inactivates tretinoin and should not be applied simultaneously.
Formulations with copolymer microspheres (RETIN-A
MICRO) or prepolyolprepolymer-2 (AVITA) that gradually release
tretinoin to decrease irritancy are available.
Adapalene
Adapalene (differin) has similar efficacy to tretinoin, but unlike
tretinoin, it is stable in sunlight, stable in the presence of benzoyl
peroxide, and tends to be less irritating at the 0.1% concentration.
Tazarotene
Tazarotene (TAZORAC, AVAGE) is a third-generation retinoid approved
for the treatment of psoriasis, photoaging, and acne vulgaris (Sami
and Harper, 2007). Tazarotene gel, applied once daily, may be used