Drugs and the skin satya. 2014 ppt

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this presentation aims at dermato pharmacotherapeutics.....at a pharmacologist's view point....only the key points are stressed.....not a complete guide....however it gives the reader, an essential basics....

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Drugs and the skin satya. 2014 ppt

  1. 1. INTERESTING FACTSINTERESTING FACTS • body’s largest organ • average adult’s skin spans 21 square feet • weighs 4.1 kg • contains more than 11 miles of blood vessels. • skin releases as much as 11 litres of sweat a day in hot weather. • skin sheds 50,000 cells every minute.
  2. 2. DRUGS AND THE SKINDRUGS AND THE SKIN DISORDERSDISORDERS DR. V.SATHYANARAYANAN M.DDR. V.SATHYANARAYANAN M.D PROFESSOR OF PHARMACOLOGYPROFESSOR OF PHARMACOLOGY
  3. 3. PHARMACOKINETICS OF SKINPHARMACOKINETICS OF SKIN • Stratum corneum is the principal barrier and reservoir • Vehicles are designed to increase hydration • Absorption varies with site • Absorption further increased in inflammation , burns , exfoliation • Occlusive dressing increases absorption by 10 fold
  4. 4. OVERVIEWOVERVIEW • Vehicles – lotion, cream, ointment, paste • Topical preparations • TREATMENT OF • Acne, Alopecia , Scabies • Seborrhoeic dermatitis (dandruff) • Psoriasis • Urticaria • Pediculosis ( lice ), Nappy rash, hyperhidrosis • Cutaneous adverse reactions
  5. 5. VEHICLES – LIQUIDVEHICLES – LIQUID FORMULATIONSFORMULATIONS • Water is the most important component • Can be a soak, a bath or a paint • Wet dressings - to cleanse, cool and relieve pruritus in acute inflammation e.g normal saline • SHAKE LOTIONS – e.g Calamine lotion – applies powder conveniently & cools skin • Can cause excessive drying •
  6. 6. CREAMSCREAMS • These are emulsions • Cosmetic vanishing creams, cold creams • Oil-in-water creams- aqueous cream, vehicle for water-soluble drugs • Water-in-oil creams- oily cream, used on hairy parts, vehicle for lipid soluble drugs
  7. 7. OINTMENTSOINTMENTS • Greasy and thicker than creams • By occlusion promote dermal hydration • Used in chronic dry conditions • Water-soluble ointments- easily washed off • Non-emulsifying ointment- adhere to skin, a form of occlusive dressing, messy, e.g- paraffin ointment- for chronic dry, scaly conditions
  8. 8. PASTESPASTES • Very adhesive, give good protection to small areas • Prevent spread of drug into surroundings • Absorb discharge • E.g coal tar paste, lassar’s paste • COLLODIONS- prep of cellulose nitrate, irritant, inflammable, used in small areas
  9. 9. TOPICAL PREPARATIONSTOPICAL PREPARATIONS • Demulcents, Emollients, • Adsorbants • Astringents • Irritants , counter-irritants • Topical analgesics • Caustics, escharotics, keratolytics • Antipruritics • Topical steroids • Sunscreens, • melanising agents, demelanising agents • Miscellaneous
  10. 10. DEMULCENTSDEMULCENTS • Inert substances which sooth inflamed skin/ denuded mucosa • Applied as thick colloidal solutions in water • Eg Gum acacia, gum tragacanth • Methylcellulose used in nasal drops, contact lens solutions • Propylene glycol in cosmetics • Glycerine – dry skin, cracked lips
  11. 11. EMOLLIENTSEMOLLIENTS • Hydrate , sooth, smoothen dry scaly conditions – olive oil, arachis oil, cocoa butter, liquid paraffin • Short-lived action • Barrier Preparations- dimethicone cream, Protect skin from discharges and secretions, irritant • Silicone sprays – pressure sores • Masking creams- titanium oxide in an ointment base • Dusting powders- zinc ,starch, talc- cool, lubricate, reduce friction
  12. 12. ADSORBANTSADSORBANTS • Finely powdered solids that bind irritants to their surface • Also Afford physical protection to the skin • Magnesium/ zinc stearate • Boric acid • aloe vera gel • Feracrylum – stops oozing blood • Sucralfate (topical ) – applied on bed sores, burns
  13. 13. ASTRINGENTSASTRINGENTS • Substances that precipitate proteins in the superficial layer • Toughen the surface, decrease exudation • Eg tannic acid, tannins used for bleeding gums • Ethanol, methanol prevents bed sores, used as after- shave • Heavy metal ions – alum, zinc
  14. 14. IRRITANTSIRRITANTS • Stimulate sensory nerve endings  produce cooling or warmth, pricking and tingling • Rubefacients – cause local hyperemia • Vesicants – form raised vesicles
  15. 15. COUNTER-IRRITANTSCOUNTER-IRRITANTS • Turpentine oil, eucalyptus oil • When massaged  relieve headache, muscular pain • Camphor – produces cooling sensation of skin, added in pain balms • Thymol, methyl salicylate • Menthol – from mint – has cooling, soothing action • Mustard plaster, capsaicin, canthridin
  16. 16. TOPICAL ANALGESICSTOPICAL ANALGESICS • Counterirritants and rubefacients- stimulate nerve endings in intact skin , relieve pain in skin, viscera or muscle supplied by same nerve root -e g salicylates, menthol, camphor, capsaicin • Topical NSAIDs - Relieve musculoskeletal pain • Local Anesthetics- lidocaine and prilocaine available as gels, ointments and sprays • Volatile aerosol sprays- sports people use, produces analgesia by cooling and placebo effect
  17. 17. CAUSTICS AND ESCHAROTICSCAUSTICS AND ESCHAROTICS • Caustic – corrosive,escharotic – cauterizer • Cause local tissue destruction and sloughing • Used to remove moles, warts • Eg podophyllum resin, silver nitrate, phenol, trichloroacetic acid
  18. 18. KERATOLYTICSKERATOLYTICS • Dissolve the intercellular substance in the horny layer of skin • Used on hyperkeratotic lesions like corns, warts, ring worm , psoriasis etc • Eg salicylic acid- applied under polyethylene occlusive dressing • Resorcinol • Urea
  19. 19. ANTIPRURITICSANTIPRURITICS • Histamine and other autocoids involved • Generalized pruritus – treat the cause, oral H1 Antihistamines, sedatives • Localized pruritus – covering the lesion, topical corticosteroids for eczema, application of aqueous menthol cream, calamine, astringents ( tannic acid ), crotamiton • Local anesthetics, topical antihistamines induce allergic dermatitis and better avoided
  20. 20. ADRENOCORTICAL STEROIDSADRENOCORTICAL STEROIDS • Suppress inflammation, immune responses • Antimitotic activity- useful in psoriasis • Vasoconstriction reduces entry of inflammatory cells • Used For Symptom Relief, apply thinly for short duration • Most useful in eczematous disorders • Choose appropriate vehicle and potency • Use combined with antimicrobials if infection present
  21. 21. TOPICAL STEROIDSTOPICAL STEROIDS • VERY POTENT- clobetasol – needed for lichen planus, DLE • POTENT- beclomethasone, fluocinolone • MODERATELY POTENT- Clobetasone • MILDLY POTENT- hydrocortisone (0.1- 1%)- adequate for eczema • Intralesional injections occ. used
  22. 22. ADVERSE EFFECTSADVERSE EFFECTS • Mild- mod potent are Effective and safe • Infection may spread • Skin atrophy occur in long term use • Local hirsutism • Depigmentation, acne • Allergic dermatitis • Potent steroids - not applied on face • On eyelids enter eye cause glaucoma • Rebound exacerbation of disease after abrupt cessation
  23. 23. SUNSCREENSSUNSCREENS • Substances that protect the skin from harmful effects of exposure to sunlight • Para-aminobenzoic acid, camphors absorb UVB ( protection against sunburn, tanning, skin cancer, aging) • Benzophenone absorb UVA which cause skin cancer, aging • Titanium dioxide, zinc oxide, calamine act as a physical barrier to UVA, UVB ( reflect ) • Useful in photosensitivity due to drugs or disease • Sunburn can be treated with oily calamine lotion, topical steroids, NSAIDs
  24. 24. SUNSCREENSSUNSCREENS • Performance of a sunscreen is expressed as SPF ( sun protective factor ) • Daily application protects more • Useful in drug induced phototoxicity • Facilitate tanning • Adjuncts in vitiligo therapy
  25. 25. PHOTOSENSITIVITYPHOTOSENSITIVITY • Doxycycline • Sulphonamides, Chlorpromazine • Frusemide, thiazides • piroxicam • TREATMENT- withdraw the offending drug
  26. 26. INTERESTING FACTS ABOUTINTERESTING FACTS ABOUT SKINSKIN • White skin appeared just 20,000 to 50,000 years ago, • as dark-skinned humans migrated to colder climates and lost much of their melanin pigment. • In a lifetime the average person sheds enough skin cells to fill an entire 2 story house. • Every square inch of the human body has about 19,000,000 skin cells.
  27. 27. MELANIZING AGENTSMELANIZING AGENTS • Drugs that promote repigmentation of vitiliginous areas of skin • Psoralen – stimulate melanocytes and induce their proliferation • Methoxsalen, trioxsalen • Sensitize skin to sunlight • Topically or orally and vitiliginous area is exposed to sunlight under supervision
  28. 28. DEMELANISING AGENTSDEMELANISING AGENTS • Lighten the hyperpigmented patches on skin • Hydroquinone – inhibits tyrosinase, decrease formation and increase degradation of melanosomes • Used for melasma, chloasma of pregnancy etc – incomplete response • Monobenzone- destroys melanocytes • Azelaic acid – weak agent
  29. 29. MISCELLANEOUSMISCELLANEOUS • Squalene used in prevention of bedsores • TARS- mild antiseptic, antipruritic, inhibit keratinization in psoriasis • Zinc oxide- astringent, barrier • Urea- topically used to assist skin hydration in ichthyosis • Insect repellents – deet, dimethyl phthalate
  30. 30. • IF IT’S WET, DRY IT;
  31. 31. There is an ancient story ... man asked God, "God, why did you make women so pretty?“ "So you will like them," God answered. And man asked God, "Why did you make women so soft? "So you will like them," God answered again. "And why," asked man again, "did you make them so stupid?“ And God answered, "So they will like you."
  32. 32. ACNEACNE • Androgen  increases sebum  with abnormal keratin form debris  plugs follicle, propionibacterium acnes colonizes  releases inflammatory fatty acids irritate ducts  comedones are formed • Apply mild keratolytics- benzoyl peroxide, azelaic acid, salicylic acid • Systemic or topical antimicrobial therapy low dose erythromycin, tetracycline
  33. 33. ACNEACNE • VITAMIN A DERIVATIVES- Tretinoin topically, may promote skin cancer, teratogenic • Adapalene- better tolerated synthetic retinoid • Isotretinoin- highly effective, used only in severe cases as it’s a serious teratogen, raise Cholesterol, TG, cause depression • HORMONE THERAPY- Estrogen, cyproterone, cyclical use of OCPills • Topical corticosteroids should not be used
  34. 34. ALOPECIAALOPECIA • MALE PATTERN BALDNESS- Topical minoxidil in UPTO 50% people some hair growth • ALOPECIA AREATA- Finasteride by mouth, PUVA
  35. 35. SCABIESSCABIES • Caused by Sarcoptes scabiei • Permethrin dermal cream • Topical Benzyl benzoate emulsion • Topical Gamma benzene hexachloride • Topical crotamiton in children • Oral ivermectin single dose  recently • Apply to all members, change bed clothes after application
  36. 36. ANTI-SEBORRHEICSANTI-SEBORRHEICS • Drugs effective in seborrheic dermatitis characterized by erythematous, scaly lesions ( dandruff )
  37. 37. SEBORRHOEIC DERMATITISSEBORRHOEIC DERMATITIS (DANDRUFF)(DANDRUFF) • Shampoo containing selenium sulfide, zinc pyrithione or coal tar • Ketoconazole shampoo in more severe cases • Keratolytics –salicylic acid • Sulfur, resorcinol – mildly effective • Occasionally corticosteroid lotion
  38. 38. PSORIASISPSORIASIS • An Immunological disorder • Manifests as localised or widespread erythematous scaling lesions or plaques • Increased proliferation , inflammation of epidermis and dermis • Drugs can decrease lesions but not cure
  39. 39. PSORIASISPSORIASIS • Topical Emollients, keratolytics, antifungals • Dithranol paste • Topical adrenal steroids- primary drugs • Vitamin D – calcipotriol topically • Vitamin A derivatives – acitretin • PUVA therapy – psoralen followed by ultraviolet light , used in severe cases • Ciclosporin , methotrexate
  40. 40. URTICARIAURTICARIA • ACUTE URTICARIA, ANGIOEDEMA  H1 blockers, cortico steroids, adrenaline for severe cases • Cyproheptadine preferred for physical urticarias • CHRONIC URTICARIA – responds to cetirizine, loratadine
  41. 41. PEDICULOSIS ( LICE )PEDICULOSIS ( LICE ) • Permethrin two applications 7 days apart • Insecticides like Carbaryl or malathion
  42. 42. NAPPY RASHNAPPY RASH • PREVENTION - Rinse reusable nappies with soaps, Use emollient cream to protect skin, Costly disposable nappies • TREATMENT – MILD- zinc cream or calamine lotion • Severe- topical steroid with antimicrobial
  43. 43. HYPERHIDROSISHYPERHIDROSIS • Astringents - reduce sweat • Antimuscarinics given by iontophoresis • Botulinum toxin injection locally  axilla temporary remission for 16 weeks
  44. 44. CUTANEUS ADVERSE REACTIONSCUTANEUS ADVERSE REACTIONS • Allergic contact dermatitis – caused by antimicrobials , local anesthetics • Patients with AIDS- increased risk • Maculopapular reactions are the most frequent – ampicillin, sulfonamides, sulfonylureas • Fixed eruptions – sulfa • Pigmentation- OCPills • Treatment – remove the cause, cooling applications ,antipruritics, H1 blockers
  45. 45. IF IT’S WET, DRY IT; IF IT’S DRY , WET IT
  46. 46. Right education should help the student, not only to develop his capacities, but to understand his own highest interest -Jiddu Krishnamurti

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