Review of Pharmacology - 9E (2015)

CHAPTER
17
Other Topics and
Adverse Effects
Drugs Used in Dermatology
1. Glucocorticoids
Potency of these agents is traditionally measured using vasoconstrictor assay (area of skin
blanching). Betamethasone, clobetasol, diflorasone, halobetasol, amcinonide, desoximetasone, fluocinonide,
halcinonide, triamcinolone, flurandrenolide, hydrocortisone, mometasone, aclometasone,
dexamethasone and desonide formulations can be used topically. Betametha sone
diproprionate is most potent and hydrocortisone is least potent topically steroid. Skin atrophy
(cigarette paper skin), striae, telengictasia, purpura and acneiform eruptions are the side
effects occuring by chronic use.
2. Retinoids
These may be first generation (retinol, tretinoin, isotretinoin and alitretinoin), second generation
(acitretin), third generation (tazarotene and bexarotene) and retinoid-like (adaplene) compounds.
These are potent teratogens (contra-indicated in pregnancy) and may cause dry skin, nose
bleeds, conjuctivitis, alopecia, muscular pain, pseudotumor cerebri and mood alterations.
Betamethasone diproprionate is
most potent and hydrocortisone
is least potent topically steroid.
Skin atrophy (cigarette paper
skin), striae, telengictasia, purpura
and acneiform eruptions
are the side effects occuring by
chronic use of topical steroids.
• Tretinoin is used for acne vulgaris and as an adjunctive agent for treating
photoaging.
• Tazarotene is approved for psoriasis and acne vulgaris.
• Alitretinoin is approved only for treatment of skin manifestations of Kaposi’s
sarcoma.
• Isotretinoin is indicated for the treatment of severe nodulocystic acne vulgaris.
It may result in hyperlipidemia, myalgia and arthralgia.
• Acitretin (major metabolite of etretinate) was used for psoriasis but was
withdrawn due to very long half life (2-3 days).
• Bexarotene is used for cutaneous T-cell lymphoma. It may cause lipid
abnormalities, hypothyroidism and gastrointestinal symptoms.
3. Photochemotherapy
Ultraviolet radiations may be classified into UV-A (320-400 nm), UV-B (290-320 nm) and UV-C
(100-290 nm) according to wavelength. UV-B is most erythrogenic and melanogenic radiation.
• PUVA: 8-Methoxypsoralen (oral) followed by UV-A is approved for treatment of
vitiligo, psoriasis and cutaneous T-cell lymphoma. Major side effects include nausea,
blistering and painful erythema. It increases the risk of melanoma and squamous
cell carcinoma.
Photopheresis: After oral methoxypsoralen, leucocytes are seperated from whole
blood using extracorporeal pheresis (ECP) device and then exposed to UV-A radiation.
Irradiated cells are then returned to the patient. ECP is effective for cutaneous
T-cell lymphoma.
• Photodynamic therapy: It combines photosensitizing drugs (mostly porphyrins)
with visible light for the treatment of non-melanoma skin cancers and actinic keratosis.
4. Antimetabolites
• Methotrexate is used for moderate to severe psoriasis, pemphigus vulgaris, pityriasis
rubra, SLE, dermatomyositis and cutaneous T-cell lymphoma. Pregnancy and lactation
are absolute contra-indications.
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