This document provides an introduction and table of contents for a lecture on drugs acting on the skin and mucous membranes in animals. It discusses several topics that will be covered, including demulcents and emollients, astringents and counter-irritants, caustics and escharotics, keratolytics and wound healing agents, and topical antimicrobials. The document provides examples and classifications for many of these drug categories. It also gives brief descriptions of mechanisms of action and uses for specific agents like kaolin, emollients, charcoal, silver nitrate, and topical corticosteroids.

1. Welcome to My Lecturer
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AUTONOMIC AND SYSTEMIC PHARMACOLOGY
Lecture notes, Six semester
Drugs acting on the skin and mucous membranes of
animals
Dr. Jibachha Sah
M.V.Sc(Veterinary pharmacology),Lecturer
College of Veterinary Science, NPI, Bhojard, Chitwan, Nepal
Email:jibachhashah@gmail.com,Mob.00977-9845024121

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INTRODUCTION
Cutaneous membrane=Skin

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Table of
Contents
Drugs acting on skin and mucous membrane
Demulcent and Emollients
Dermatologic and Otic (into ear) Agents
Astringents and Counter-irritants
Caustics (Corrosive) and Escharotics (Cauterizers)
Keratolytics and Wound-healing Agents
7.Topical Antimicrobials (Antibiotics and
Antifungals) 3
Adsorbents and Protective
. Topical Antimicrobials (Antibiotics and Antifungals):

4. Demulcents
An agent that forms a soothing, protective film when administered onto a mucous membrane
surface, that can relieve irritation of the bowel lining.
They may also be applied to the skin. Most demulcents are water soluble compounds with a high
molecular weight e.g., gums, oils, mucilages, and starches.
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Maxi-Sorb Bolus is an anti-
diarrheal demulcent and used as
an aid in relief of simple non-
infectious diarrhea in horses and
cattle.

5. Classification of demulcent
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Examples are
Demulcents are used to lubricate and protect the alimentary mucous membrane,
but the term is usually applied only to those agents that affect the buccal,
pharyngeal, esophageal, and gastric mucosa

6. Mechanism of action
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A demulcent is a high molecular weight compound in aqueous solution that coats the skin
surface, thus protecting the underlying cells and alleviating irritation.
Glycerin is a popular vehicle as this trihydric alcohol is miscible with water and alcohol. It is a
hygroscopic agent that is absorbed into the skin. Similarly, propylene glycol is a good vehicle,
miscible with water and dissolving many essential oils. Linoleic acid is important for the barrier
function of the stratum corneum, (outermost layer of the epidermis) particularly in relation
to transepidermal water loss.

7. Kaolin( Antidiarrheal compound)
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a demulcent and adsorbent
The action of kaolin-pectin is believed to be related to the binding of bacterial toxins (endotoxins and enterotoxins) in the
gastrointestinal (GI) tract. However, experimental studies have shown that kaolin-pectin has been an ineffective binder of Escherichia
coli enterotoxin, and clinical studies have failed to show a benefit from the administration of kaolin-pectin.
Kaolin is a form of aluminum
silicate, and pectin is a carbohydrate
that is extracted from the rinds of
citrus fruits. This product has a
claim to act as a demulcent and
adsorbent in the treatment of
diarrhea.

8. History and Traditional Usage
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Blumenthal and others (2000), naturopathic physicians and medical herbalists prescribe mullein
for chronic otitis media and eczema of the ear.
Mullein tea is given to treat patients with influenza, catarrh, bronchitis, and tracheitis and is thought to
be effective because of the mucilage content, which coats and soothes irritated mucous membranes, and
the mild expectorant action of saponins.
The German Commission E
recognizes mullein flowers for treating
catarrh, and clinical studies have
shown antiviral action against fowl
plague virus, influenza A and B, and
herpes simplex virus (Blumenthal,
2000).

9. Emollients
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having the power of softening or relaxing, as a medicinal substance; soothing, especially to the skin:
emollient lotions for the face.
Conditioner is a premium coat and skin treatment that comes directly to pet. conditioner includes shea butter,
which is a fatty oil derived from African shea tree nuts. It ‘s widely known for its skin softening attributes and
helps balance natural oils within hair and skin.
Emollients may be used in a
lotion, cream, ointment, or
gel to prevent or treat dry,
rough, scaly, itchy skin and
other skin problems, such as
rashes or burns.
another name for an emollient is a moisturizer.

10. Classification of emollients
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11. Mechanism of action
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Emollients include fats such as lanolin, hydrocarbons such as
paraffin, petrolatum and mineral oil etc.
These agents are added to shampoos as vehicles and for their local effects in softening and protecting the
skin. Example humectants such as carboxylic acid and lactic acid and oils such as olive, cottonseed,
corn, almond, peanut and coconut oil.
Emollients soften the skin by
forming an occlusive oil film on
the stratum corneum, thus
decreasing the trans epidermal
water
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12. Emollient laxatives
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The enema preparations are all veterinary-licensed products, but the oral preparations are not.
Docusate sodium (dioctyl sodium sulfosuccinate)
•Dogs: 50–300 mg PO q.12–24 h; 10–15 mL of a 5% solution mixed with 100 mL of water and instilled per
rectum
•Cats: 50 mg PO q.12–24 h; 2 mL of a 5% solution mixed with 50 mL of water and instilled per rectum
Emollient laxatives are anionic detergents that reduce surface tension, thus increasing
the miscibility of water and lipid digesta.
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13. Atopic Dermatitis and Allergic Contact Dermatitis
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Canine atopic dermatitis
The use of an effective emollient, especially when combined with hydration therapy, helps to restore and
preserve the stratum corneum barrier and can decrease the need for topical
corticosteroids. Moisturizers are available as lotions, creams, and ointments.
Treatment with emollients is
important both during the
course of steroid treatment and
as part of long-term
management.

14. Emollients Products
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(i)Animal products (ii) Vegetable oil
a) Olive oil
(b) Arachis oil
(c) Linseed oil
(d) Oil of theobroma (cocoa butter)
(a) Wool fat (Lanolin)
(b) Wool alcohol
(c) Lard
(d) Bees Wax
(e) Spermaceti.
(iii) Petroleum Products:
(a) Soft paraffin
(b) Hard paraffin
(c) Liquid paraffin
(d) White petroleum (Vaseline)

15. Adsorbents and Protective
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When used in medicine, it physically binds to acids and toxic substances in the stomach and
digestive
Adsorbents are finely powdered, inert and insoluble solids capable of binding to their surface
(adsorbing) noxious and irritant substances. They are also called protectives because they
provide physical protection to the skin or mucosa.
Intestinal Adsorbents:
Used as a antidote to treat poisonings
following excessive oral ingestion of
certain medications or poisons.

16. Adsorbents and Protective
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Products
(i) Dermal protectives:
(a) Magnesium stearate
(b) Zinc stearate
(c) Talc (French Chalk) (hydrated
magnesium silicate)
(d) Calamine
(e) Zinc oxide
(f) Bentonite
(g) Boric acid
(h) Starch
(ii) Gastrointestinal protectives
(a) Kaolin (hydrated aluminium silicate)
(b) Pectin (Plant polysaccharide)
(c) Activated charcoal (10% susp.)
(d) Chalk
(e) Magnesium trisilicate
(f) Aluminium hydroxide
iii) Occlusive protectives:
(a) Collodion (Pyroxylon) – nitrated cellulose given
with castor oil
(b) Dimethicone (dimethyl polysiloxane, simethicone) →
form Silicone polymer-amphiphilic liquid which acts as a

17. Mechanism of action
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Active charcoal acts by binding to the pharmaceutical drugs or poisons such as organophosphates and
decreasing the systemic absorption of toxic agents.
Following the administration of activated charcoal, cathartics are indicated to evacuate the charcoal-
poison bonded complex from the gastrointestinal tract. Activated charcoal may also have an effect on
systemic drug levels by lowering the serum levels of already absorbed drugs or toxins. Many absorbed
drugs that undergo significant hepatic metabolism and conjugation are eliminated via bile into the
small intestines. When they reach the small intestines, drug conjugates can undergo hydrolysis and
return to the enterohepatic circulation. Pectin MOA-unknown
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Charcoal/Pectin

18. Astringents and Counter-irritants:
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Astringents are substances that precipitate proteins, but do not penetrate cells,
thus affecting the superficial layer only.
Counter-irritants:(Examples Capsaicin, menthol (mint oil), methyl salicylate, and camphor).
Counter-irritants are substances which are applied to the skin to cause local irritation and inflammation. The
reasoning which prompts their use is that, where a chronic inflammation exists, a counter-irritant will cause an
over-riding acute inflammation with a great increase in vascularity and consequently an increased blood supply
to the area.
An astringent (sometimes
called adstringent) is a
chemical that shrinks or
constricts body ...
In medicine, their dried form
has been used as
an astringent.

19. Astringents& Counter irritant
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Classification
(i) Tannic acid and tannins,(ii) Alcohol (ethanol and
methanol) → 50 – 90%
(a) Bismuth carbonate,(b) Alum c) Aluminium hydroxy-chloride(d) Zinc oxide(e)
Zirconyl hydroxychloride.,(f) Zinc sulfate,(g) Calamine
(
a) Tannic acid, (b) gallic acid, (c) kino, (d) Krameria, (e) rubus ( blackberry).
Volatile oil:(a) Turpentine oil,(b) Eucalyptus oil,(c) Clove oil (d) Menthol
(e)Camphor
(vii) Alcohol,(viii) Iodine,(ix) Mercuric iodide,(x)
Ammonia.
Astringents:
Methyl salicylate
Mineral astringents:
Vegetable astringents
Counter-irritants

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23. Skin irritation is known as “the production of reversible damage of the skin following the
application up to 4 hours”.
Pathological characteristics and manifestation of skin irritation such as, Erythema and edema are
manifestations of dermal irritation.
Irritation is initially manifest by redness (erythema), vesicles, serous exudates, serous scabs (eschar) and
various degrees of swelling (edema). Over time, other reactions may be manifest, like small areas of
scaling, hyperplasia, hyperkeratosis and alopecia.
Counter Irritant

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Counter irritant activity Cinnamon and Dexamethasone on Rabbit
(Imran Ahmad et. al.2014)
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25. Caustics (Corrosive) and Escharotics (Cauterizers):
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These chemicals cause local tissue destruction and sloughing. An escharotic, in addition, precipitates proteins that
exude to form a scab → gets fibrosed to form a tough scar.
They are used to remove moles, warts, condylomata, papillomas, to destroy horn buds in calves,
and on keratotic lesions. Care is needed in their application to avoid ulceration.

26. Caustics (Corrosive) and Escharotics (Cauterizers):
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Chemical used in treatment of wart, papilomas and condylomata, are
Caustic means corrosive and Escharotic means cauterizer.
These chemicals cause local tissue destruction and sloughing.
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27. How to used Silver Nitrate
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Silver nitrate is a highly caustic material, so it must be used with caution to prevent damage to healthy tissues.
Silver nitrate applicators are firm wooden sticks with 75% silver nitrate and 25% potassium nitrate
embedded on the tip. Moistening the tip sparks a chemical reaction that burns organic matter (skin),
coagulates tissue, and destroys bacteria.

28. Keratolytics and wound healing agent
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Keratolytics dissolve the intercellular substance in the horny layer of skin.
The epidermal cells swell, soften and then desquamate. They are used on hyper-keratotic lesions
like corns, warts, psoriasis, chronic dermatitis, ring worm, athletes foot, etc.

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Keratolytics and Wound
Healing Agent
Keratolytics agents
(i) Salicylic acid
(ii) Resorcinol
(iii) Benzoic acid
Wound-healing Agents
(i) Lugol’s solution (5% I2 and 10% K1 in
distilled water)
(ii) Povidone iodine oint. (betadine, isodine)
(iii) Sod. iodide
(iv) Zinc oxide
(v) Zinc sulfate
(vi) Copper naphthenate solution.

30. Dermatologic and Otic (into ear) Agents
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(i) Undecylenic acid,(ii) Dimethyl sulfoxide (DMSO),(iii) Topical Corticosteroids
DMSO is used topically to decrease pain and speed the healing of wounds, burns, and muscle and skeletal
injuries. DMSO is also used topically to treat painful conditions such as headache, inflammation, osteoarthritis,
rheumatoid arthritis, and severe facial pain called tic douloureux.

31. Classification of dermatological agent
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Based on potency
(a) Fluocinolone acetonide – 0.2%,(b) Beclomethazone dipropionate – 0.5%
(a) Fluocinolone acetonide – 0.025%,(b) Triamcinolone acetonide – 0.1%,(c)
Hydrocortisone butyrate – 0.1%,(d) Flucortolone – 0.5%,(e) Betamethazone valerate
– 0.1% (f) Betamethazone benzoate – 0.025%,(g) Betamethazone dipropionate –
0.05%,(h) Beclomethazone dipropionate – 0.025%
(i) Flumethasone pivalate – 0.02%,(ii) Fluocinolone acetonide – 0.01%,(iii)
Flucocortolone – 0.2%,(iv) Hydrocortisone – 1.0% with urea.
(i) Dexamethasone – 0.01%,(ii) Hydrocortisone acetate –
0.1-1%,(iii) Methyl prednisolone – 0.025%
A. Very Potent:
B. Potent:
C. Moderately Potent:
D. Mild:

32. Topical Antimicrobials (Antibiotics and Antifungals):
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A. Antibiotics
Neomycin sulfate (Nebasulf, Neosporin)
Polymyxin B (Nebasulf and, Neosporin)
Framycetin (Soframycin powder) – 1% Cream.
Oxytetracycline (Terramycin skin oint) – 3%
Acyclovir (Herpex cream) – 5%
Gentamicin Sulfate
Chloramphenicol
Nystatin (Mycostin)
Povidone iodine
Metronidazole

33. Topical Antimicrobials (Antifungals):
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Antifungals:
Miconazole
Enilconazole
Amitraz (in Demodectic mange)
Malachite green (used in fish)
Formaldehyde solution (used in fish)
Clotrimazole
Cuprimyxin
Ketoconazole
Copper sulfate
Benzyl benzoate 25%

34. Local anaesthesia
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Lignocain HCl
Lidocaine topical (for use on the skin)
is used to reduce pain or discomfort
caused by skin irritations such as
sunburn, insect bites, poison ivy, poison
oak, poison sumac, and minor cuts,
scratches, or burns. Lidocaine topical is
also used to treat rectal discomfort
caused by hemorrhoids.
Amethocain,Benzocain
Benzocaine belongs to a group of medicines known as topical
local anesthetics.
This product is available in the following dosage forms:
Solution
Gel/Jelly
Spray
Liquid
Ointmen

35. Lignocain topical
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Before use on the skin, clean and dry the affected area as directed. Apply a thin layer
of medication to the affected area of skin, usually 2 to 3 times a day

36. Ophthalmic Agents (on eye):
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Antibiotic preparation
Kanamycin sulfate Ophthalmic oint
Chloramphenicol Ophth. Oint
Gentamicin sulfate Ophthalmic solution and oint
Neomycin SO4 (1700 units)-Polymyxin B (5000 unit)
Acyclovir ophth. oint. (Ocuvir)-3%
Boric acid Ophth. oint. (1%)
Oxytetracycline hcl oint
Norfloxacin solution
Sulphacetamide solution
Framycetin sulf. oint

37. Mydriatics and Miotics:
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Phenylephrine hcl (Drosyn eye drop) – 5% and 10%
Miosis or myosis is excessive constriction of the pupil. Mydriasis, is
the dilation of the pupil.
Tropicamide solution (Mydriacyl) – 1%
Atropine Sulf. ophth. oint (Atrophate) – 1%
Pilocarpine hcl solution (Pilocar) – 1%, 2%, 4%

38. Any Questions?