This document summarizes dermatological pharmacology. It discusses the structure of skin and topical vehicles like creams, lotions, gels and ointments used to deliver drugs to the skin. It also discusses various drug classes used in dermatology like glucocorticoids, retinoids, antibiotics, antifungals and immunomodulators. Specific drugs covered include tretinoin, adapalene, isotretinoin, calcipotriene and phototherapy agents. It also provides information on treatment of conditions like acne, hyperpigmentation and photoprotection with sunscreens.

1. Dermatological
pharmacology
Dr. Ankita Bist
Assistant Professor
Department of Pharmacology

2. STRUCTURE OF SKIN

3. GLUCOCORTICOIDS
 Immunosuppressive and anti-inflammatory properties
 Administration: locally and systemically.
 Systemic therapy restricted to severe dermatological illnesses.
 Side effects: Skin atrophy, striae, telangiectasias, purpura, and
acneiform eruptions.
 Topical glucocorticoids have been grouped into seven classes in
order of decreasing potency.

5. TOPICAL VEHICLES
Creams:
 Less greasy and most acceptable
 Applies more easily
 Can be drying
 Easy to wash off
Lotions:
 More water content and less viscous
than creams
Gels:
 Water-soluble emulsion with gelling
agent
 Can be drying
 Concentrates drug at surface after
evaporation
Ointments:
 Alleviates dryness by prevention of
evaporation
 Enables medication to penetrates
skin well
 Water repellant
 Remains on the skin
 Occlusive and protective
 Soothing and lubricating

6. TOPICAL RETINOIDS
 Cornerstone of acne therapy.
 ACTION: Targets the abnormal follicular epithelial hyper
proliferation → reduces follicular plugging → reduces
microcomedones and both non inflammatory and inflammatory acne
lesions.
 Biological effects mediated through: nuclear hormone receptors
(retinoic acid receptor RAR and retinoids X receptor RXR) and
cytosolic binding proteins.
 CURRENTLY AVAILABLE: Tretinoin, adapalene, tazarotene,
isotretinoin, and β-retinoyl glucuronide.

7. TRETINOIN
 Potent comedolytic: promotes lysis of keratinocytes, prevents cells from
binding to each other, hence comedones, which are horny impactions in
follicles, cannot form. 6-10 weeks to produce action
 Highly efficacious, but response is delayed. 0.05% gel
 Side effects: feeling of warmth, stinging, excessive redness, edema and
crusting.
 Teratogenic effect with topical retinoic acid is minor because of low blood
levels produced; but not recommended for use during pregnancy.

8. ADAPALENE
 Newer synthetic tretinoin like drug which binds directly to the
nuclear retinoic acid receptor and modulates keratinization and
differentiation of follicular epithelial cells.
 Also exerts anti-inflammatory action, comedone formation is
suppressed. 0. 1% gel
 In acne vulgaris, as effective but less irritating than tretinoin.

9. TAZAROTENE
 Topical synthetic retinoid used for psoriasis (0.05%-1 %)
gel
 Prodrug is hydrolysed in the skin to tezarotenic acid
that exerts antiproliferative and anti inflammatory
action by binding to retinoic acid receptor: modification
of gene function.

10. ADVERSE EFFECTS
 The main adverse effect - primary irritant dermatitis, which can
present as erythema, scaling, burning sensation and can vary
depending on skin type, sensitivity, and formulations.
 Lessened by concomitant use of emollients.
 Photosensitivity reactions.

11. ORAL ISOTRETINOIN
 Indication - moderate-to-severe acne or lesser degree of acne producing
physical or psychological scarring, unresponsive to conventional therapy.
 The approved dose - 0.5–1 mg/kg/day, usually given for 20 weeks.
Alternatively, lower dose can be used for longer period, with a total
cumulative dose of 120 mg/kg.
 Reduces production of sebum, corrects abnormal keratinization of follicles
and causes dramatic improvement.
 Systemic retinoids approved for the treatment of acne, psoriasis, and
Cutaneous T cell Lymphoma.

12. ACITRETIN
 Synthetic retinoid for oral use
 Recalcitrant, pustular and severe forms of psoriasis
 A/E: Dryness of skin and eyes, arthralgis, myalgia, liver damage,
lipid abnormalities
BEXAROTENE
 CTCL

13. ADVERSE EFFECTS
 Retinoid dermatitis: characterized by erythema, pruritus, and
scaling.
 Very rarely, patients may develop pseudotumor cerebri, especially
when combined with tetracyclines.
 chronic administration at higher doses can cause diffuse idiopathic
skeletal hyperostosis (DISH) syndrome, premature epiphyseal
closure, and other skeletal abnormalities
 Teratogenic (accutane embryopathy) craniofacial, heart, CNS
abnormalities.

14. VITAMIN ANALOGUES
Calcipotriene:
 Topical vitamin D analogue used in the treatment of plaque psoriasis.
 Mild to moderate psoriasis.
 Adverse effects: Skin irritation, scaling,hypercalcemia and
hypercalciuria
 Used off label for multiple conditions, including morphea, vitiligo, and
congenital ichthyoses.

15. PHOTOCHEMOTHERAPY
 UV or visible radiation is used to induce a therapeutic
response either alone (phototherapy) or in the presence of
an exogenous photosensitizing drug (photochemotherapy).
 PUVA- Photoreactions interfere with pyrimidine bases and
inhibit DNA synthesis and epithelial cell turnover.
 Photopheresis: Peripheral blood mononuclear cells are
treated with psoralens
 Photodynamic therapy: Photodynamic drugs and visible light

17. SUNSCREEN
 Sunscreen is a lotion, spray, gel or other topical product that
absorbs or reflects the sun's ultraviolet (UV) radiation and
provide temporary photoprotection to the skin.
 Regular use is efficacious in reducing photocarcinogenesis and
photoaging.

18. SUN RADIATION SUMMARY
Radiation
Type
Characteristic
Wavelength (
Effects on Human Skin Visible to
Human Eye?
UVC ~200-290 nm
(Short-wave UV)
DNA Damage No
UVB ~290-320 nm
(Mid-range UV)
Sunburn
DNADamage
Skin Cancer
No
UVA ~320-400 nm
(Long-wave UV)
Tanning
Skin Aging
DNADamage
Skin Cancer
No
Vis ~400-800 nm None
Currently Known
Yes
IR ~800-120,000 nm
Increasing
Heat Sensation
(high  IR)
No

19. SPF
 SPF Value = MED (PS) / MED (US)
MED (PS) : minimum erythemal dose for protected skin
MED (US) : minimum erythemal dose for unprotected skin
 Most sunscreen SPF- 15
 UV A protection: CW method

20. SOME ACTIVE SUNSCREEN INGREDIENTS
 Inorganic Agents: zinc oxide and titanium dioxide. They provide UVA
and UVB protection.
 Organic UVA Filters: Include benzophenones (oxybenzone,
dioxybenzone, sulisobenzone); dibenzoylmethanes (avobenzone);
anthralates (meradimate); and camphors (ecamsule).
 Organic UVB Filters: There are numerous UVB filters, including
aminobenzoates (PABA and padimate O); cinnamates (cinoxate,
octinoxate); salicylates (trolamine salicylate, homosalate, octisalate);
octocrylene; and ensulizole.

21. ANTIHISTAMINES
 Oral antihistamines, particularly H1 receptor antagonists,
hydroxyzine, diphenhydramine, promethazine, cetirizine,
levocetirizine etc. are useful for the control of pruritus.

22. ANTIBIOTICS
 Agents such as tetracyclines, macrolides, and dapsone, also have
anti-inflammatory properties, which make them useful for non-
infectious conditions, such as acne vulgaris, rosacea, granulomatous
diseases, neutrophilic dermatoses, and autoimmune bullous diseases.
 Topical agents are very effective for the treatment of superficial
bacterial infections and acne vulgaris.
 Systemic antibiotics also are prescribed commonly for acne,
cutaneous Bacterial Infections and deeper bacterial infections.

23. ACNE
 A multifactorial chronic inflammatory disease of pilosebaceous units.
 Pathogenesis—
• Increased sebum productions
• Follicular hyperkeratinization
• Propionibacterium acne (P. acne) colonization and
• Inflammation
 Lesions may present as non inflammatory comedones or inflammatory
papules.
 Inflammatory cysts may leave behind hyper-pigmentation and
sometimes scarring.

24. CLINICAL FEATURES - SEVERITY
 MILD: Mainly comedones with few papules/pustules.
 MODERATE: Moderate papules and pustules (10-40) and comedones (10-
40).
 MODERATELY SEVERE: Numerous papules and pustules (40-100) and many
comedones (40-100). May have nodular inflamed lesions (upto 5). Wide
spread involvement of face, chest and back.
 SEVERE: Nodulocystic acne and acne conglobata with many nodular or
pustular lesions.

25. TOPICAL ANTIMICROBIALS
 Commonly used in acne include benzoyl peroxide, clindamycin,
erythromycin, and antibiotic–benzoyl peroxide combinations.
 Topical monotherapy with clindamycin or erythromycin is not
recommended.
 Other topical antimicrobials used in treating acne include azelaic acid,
dapsone, metronidazole, sulfacetamide, and sulfacetamide/sulfur
combinations.

26. SYSTEMIC THERAPY
 For patients with acne vulgaris that is more extensive or resistant to
topical therapy.
 Commonly used: tetracyclines (doxycycline, minocycline,) macrolides
(azithromycin, erythromycin); and trimethoprim-sulfamethoxazole.
 6–8 weeks is required for visible clinical results

27. ANTIFUNGAL THERAPY
 COMMON SUPERFICIAL CUTANEOUS MYCOSES: The dermatophyte
infections (tinea corporis, crurus, and pedis)- Azoles, griseofulvin,
terbinafine, nystatins etc.
 SUPERFICIAL MUCOCUTANEOUS MYCOSES: Such Tinea, pityriasis
versicolor, seborrheic dermatitis, cutaneous candidiasis etc
respond to Nystatin, Azoles, allylamines, Ciclopirox, butenafine
etc.

28. CYTOTOXIC AND
IMMUNOSUPPRESSANT DRUGS
 For immune
mediated diseases
such as psoriasis,
autoimmune
blistering diseases,
and leukocytoclastic
vasculitis

29. BIOLOGICAL IMMUNOMODULATORS
AND OTHER AGENTS
 A number of biologic medications have been introduced to treat
psoriasis and other autoimmune diseases as Atopic Dermatitis by
binding to TNF alpha and preventing it from communicating with
cells.
 Adalimumab, Etanercept, Infliximab, Secukinumab and
Ustekinumab which are mainly monoclonal antibodies directed
against TNF- alpha.
 Intravenous Immunoglobulin
 Targeted Antineoplastic Agents: Vismodegib and sonidegib (basal
cell carcinoma)

30. TREATMENT OF
HYPERPIGMENTATION
 Sun protection or avoidance is a vital component of any treatment regimen.
 Hydroquinone- decreases melanocyte pigment production by inhibiting
tyrosinase. In addition, it causes degradation of melanosomes and
destruction of melanocytes
 Azelaic acid, inhibits tyrosinase activity but is less effective than
hydroquinone. Has mild comedolytic, antimicrobial, and anti-inflammatory
properties, so often used in acne.
 Mequinol a competitive inhibitor of tyrosinase- permanent depigmentation.
 Glycolic acid is an α-hydroxy acid used in chemical peels.

31. THANK YOU