Fundamentals of Pharmacology for Veterinary · PDF fileFundamentals of Pharmacology for Veterinary Technicians Chapter 18 Table 18-1 ... Fundamentals of Pharmacology for Veterinary

Fundamentals of Pharmacology for Veterinary Technicians Chapter 18

Figure 18-1Copyright © 2011 Delmar, Cengage Learning






Figure 18-4ACopyright © 2011 Delmar, Cengage Learning

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Figure 18-4BCopyright © 2011 Delmar, Cengage Learning

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Table 18-1Copyright © 2011 Delmar, Cengage Learning

Table 18-1 Routes of Administration for Ophthalmic Drugs

Route of Administration

Tissues Reached Formulation Advantages Disadvantages Comments

Topical • Cornea• Conjunctiva• Anterior uvea• Eyelids• Nasolacrimal

system

• Drops• Solutions• Suspensions

• Easier administration in small animals

• Minimal visual impairment

• Lower incidence of contact dermatitis

• More diffi cult administration in large animals

• Less contact time with cornea

• More frequent application than ointments

• Diluted by tear production

• More systemic absorption possible

• More than 1 drop rarely indicated per dose

• Allow 5 minutes between drops

• Instill in order of least viscous to most viscous

• Instill water-based products prior to oil-based products

• Ointments • Longer contact time

• Less frequent administration

• Protects cornea from drying

• Not diluted by tear production

• Less expensive than drops

• Temporary blurring of vision

• More diffi cult administration

• More contact dermatitis

• Do not use with penetrating corneal wounds

• Diffi cult to determine exact dose

• Ensure that client understands that the tube should not contact the eye

Subconjunctival injection

• Cornea• Anterior uvea

• Sterile solutions and suspensions

• Longer duration of action

• Higher anterior chamber concentrations versus topical

• May create scar tissue

• Temporary pain

• Improved compliance

• Used for drugs with poor corneal penetration

Retrobulbar injection • Vitreous chamber

• Optic nerve

• Sterile solutions and suspensions

• Used to instill local anesthetic for removal of bovine eye

• Antibiotics may be given via this route to treat intraocular infections or retrobulbar cellulitis

• Infrequently used except for treatment of orbit or posterior half of the globe

• Primarily used for local anesthetic

Systemic drugs • Eyelids• Vitreous

chamber• Optic nerve• Anterior uvea• Nasolacrimal

system

• Oral• Intramuscular• Subcutaneous• Intravenous

• Allows drug penetration to areas where topical therapy is inadequate

• Systemic toxicity• Does not reach

cornea

• See information under specifi c drug section



Table 18-2 Ophthalmic Anti-Infectives, Anti-Infl ammatories, and Tear Supplements

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Topical antibacterial drugs (read labels to determine if glucocorticoids are used in these preparations)

bacitracin (Mycitracin®, Trioptic-P®, Vetropolycin®, Neosporin® Ophthalmic)

Works against gram-positive organisms; usually found in combination with neomycin and

polymyxin B (Mycitracin®, Trioptic-P®, Vetropolycin®, Neosporin® Ophthalmic)

Works against gram-negative organisms; usually used in combination with bacitracin and neomycin

oxytetracycline (Terramycin®) Broad-spectrum antibiotic that is effective against Chlamydia sp.; may be used in combination with other drugs

tetracycline (Achromycin®, Aureomycin®) Broad-spectrum antibiotic that is effective against Chlamydia sp.

aminoglycosides• gentamicin (Gentocin®, Garamycin®,

Genoptic®, OptVet®)• tobramycin (Tobrex®)• neomycin (Mycitracin®, Trioptic-P®,

Vetropolycin®, Neosporin® Ophthalmic)

Work against Staphylococcus sp. and gram-negative organisms, including Pseudomonas sp.; may be formulated alone or with corticosteroids; neomycin is a broad-spectrum antibiotic usually used in bacitracin and in combination with polymyxin B

erythromycin (Ilotycine Ophthalmic®, Ak-Mycin®)

Broad-spectrum antibiotic; usually used for gram-positive infections

fl uoroquinolones• ciprofl oxacin (Ciloxan®)• norfl oxacin (Chibroxin®)• ofl oxacin (Ocufl ox®)• moxifl oxacin (Vigamox®)

Broad-spectrum antibiotic

chloramphenicol (Bemacol®, Chlorbiotic®, Chloricol®, Vetrachloracin®, Chlorasol®)

Broad-spectrum antibiotics; handle with care due to human side effects; cannot use in food-producing animals

sulfonamides• sulfacetamide (Bleph-10®)

Broad-spectrum antibiotic

Topical antifungal drugs* natamycin (Natacyn-Ophthalmic®) Works in treating mycotic keratitis (mainly Fusarium sp., Candida sp., Aspergillus sp.)

Topical antiviral drugs • idoxuridine (Stoxil®)• trifl uridine (Viroptic®)• vidarabine (Vir-A Ophthalmic®)• acyclovir (compounded)

Used to treat viral infections of the eye, mainly in cats (ocular herpes). These drugs interrupt viral replication and are virostatic, not virucidal; treat resolution

Topical glucocorticoid drugs

• prednisolone acetate drops (Pred Mild®, Econopred®, PredForte®)

• prednisolone sodium phosphate drops (generic brands)

• dexamethasone drops and ointment (Decadron Phosphate®, Maxidex®)

• loteprednol etabonate (Alrex®)

Glucocorticoids are used to treat infl ammation of the conjunctiva, sclera, cornea, and anterior chamber. Penetration to the vitreous chamber and eyelids is poor. Glucocorticoids delay healing and should not be used in patients with corneal ulcers, fungal infections, or viral infections

(Continued)


Table 18-2 continuedCopyright © 2011 Delmar, Cengage Learning

Table 18-2 (Continued )


• triple antibiotic with hydrocortisone (Neobacimyx H®, Trioptic-S®, Vetropolycin HC®)

• triple antibiotic with dexamethasone (Maxitrol®)

• neomycin with isofl upredone acetate (Neo-Predef®)

• gentamicin with betamethasone (Gentocin Durafi lm®)

• chloramphenicol with prednisolone (Chlorasone®)

• sulfacetamide with prednisolone (Blephamide Liquifi lm®)

Topical nonsteroidal anti-infl ammatory drugs

• fl urbiprofen sodium (Ocufen®)• ketorolac tromethamine (Acular®)• diclofenac sodium (Voltaren®)• suprofen sodium (Profenol®)• bromfenac (Xibrom®)• nepafenac (Nevanac®)

Topical NSAIDs are used to treat infl ammation, usually after surgery

Tear supplements • artifi cial tears (Bion Tears®, Liquifi lm Tears®, Hypotears®, Adsorbotear®)

• lubricants (Lacri-Lube S.O.P.®, Akwa Tears®, DuraTear® Naturale)

Artifi cial tears are isotonic, pH-buffered solutions that lubricate dry eyes and provide eye irrigation. Lubricants are petrolatum-based products that lubricate and protect eyes (mainly used during anesthesia, in which the eyes may remain open while tear production is reduced)

* Other topical antifungal drugs used to treat ocular infections include amphotericin B, povidone iodine, miconazole, and itraconazole. Topical forms of these antifungal drugs are compounded.



Table 18-3 Otic Drugs


Topical antibiotic otic drugs

• aminoglycosides:• gentamicin (Otomax®, Getocin Otic

Solution®, Tri-Otic®, GentaVed Otic®);

• neomycin sulfate (Tresaderm®, Panalog®, Tritop®)

Broad-spectrum antibiotics that are usually combined with a glucocorticoid, antifungal agent, and/or antiparasitic agent. Neomycin sulfate products also contain thiostreptin, a gram-positive antibiotic; tympanic membrane should be intact when using this medication; aminoglycosides are ototoxic.

• thiostreptin (Tresaderm®, Panalog®, Tritop®)

Gram-positive antibiotic that is usually combined with a glucocorticoid, antifungal agent, and/or antiparasitic agent.

• chloramphenicol (Liquichlor®, Chlora-Otic®)

Broad-spectrum antibiotic usually combined with a glucocorticoid and/or topical anesthetic. Do not use in food-producing animals. Handle this drug with caution.

• fl uoroquinolones:• enrofl oxacin (Baytril Otic®)

Broad-spectrum antibiotic that is combined with silver sulfadiazine (has both antifungal and broad-spectrum antibacterial properties).

Topical antiparasitic otic drugs

• thiabendazole (Tresaderm®) Used to treat ear mites in dogs and cats.

Thiabendazole has antiparasitic and antifungal properties.

Preparation may contain an antibiotic (such as neomycin) and a glucocorticoid (such as dexamethasone).

• pyrethrins (Mita-Clear®, Cerumite®, Aurimite®)

Used to clear mite infestations of the ear; treatment should continue for at least three weeks.

• milbemycin oxime (MilbeMite®) Used to treat ear mite infestations in cats and kittens four weeks of age and older.

Treatment consists of administering solution from one tube per ear as a single treatment. MilbeMite® is available in a foil pouch that contains two tubes of solution (one tube for each ear).

Milbemycin oxime is also available orally.

• ivermectin:• injectable (Ivomec®) Injectable treatment that is given SQ extra-label to treat

ear mites in dogs and cats.

• topical (Acarexx 0.01 percent suspension®)

Otic solution is labeled for use in cats and kittens (more than four weeks of age) and is packaged in ampules.

• selamectin (Revolution®) Once-monthly treatment for ear mites in cats; applied to dorsal cervical skin; (also protects against heartworms, roundworms, hookworms, mange mites, the American dog tick, and fl eas).

Topical otic antifungal agents

• clotrimazole (Otibiotic®, Otomax®) Works against Malassezia, Microsporum, Trichophyton, Epidermophyton, and Candida fungi; antifungal agent is combined with gentamicin and betamethasone.

(Continued)





• nystatin (Dermagen®, Panalog®, Derma-Vet®, Dermalone®)

Works against Candida fungi; antifungal agent is combined with neomycin sulfate, thiostreptin, and triamcinolone.

• miconazole (Conofi te®) Works against Microsporum and Trichophyton; local irritation may be seen with miconazole treatment.

• thiabendazole (Tresaderm®) Works against Microsporum and Trichophyton; also contains antiparasitic, antibiotic, and glucocorticoid.

Topical otic drying agents

Various products that contain salicylic acid, acetic acid, boric acid, or tannic acid. Examples include Dermal Dry®, VetMark Ear Powder®, OtiRinse Cleansing/ Drying Ear Solution®, Oti-Care-B®

Reduces moisture in the ear to help prevent or treat certain infections of the ear. Ears should be cleaned prior to putting in drying agents.

Topical otic cleansing agents/local anesthetics

Various products contain antibiotics, antiseptics (such as chlorhexidine and povidone iodine), and/or anesthetics/soothing agents (such as lidocaine). Examples include Solvaprep®, Epi-Otic®, Oti-Clens®, Fresh-Ear®

Used to clean ears and control odor. Also used for gentle fl ushing of the ear using a bulb syringe or tubing. Ears should be dried thoroughly after use.

Topical otic dewaxing agents

Various products that contain cerumen softeners or drying agents such as benzyl alcohol, cerumene, and similar chemicals. Examples include Cerulytic® and Cerumene®.

Used to remove debris and wax before treatment with topical medications, and to aid in wax removal by fl ushing of the ear with a bulb syringe or tubing.

Topical anti-infl ammatories

• fl uocinolone plus DMSO (Synoptic®) DMSO enhances percutaneous absorption of glucocorticoids. Avoid contact with human skin to reduce risk of absorbing the drug.

• hydrocortisone (Buro-Otic®, Clearx® Ear Treatment)

Glucocorticoids are used to reduce infl ammation association with local irritation.



Table 18-4 Ophthalmic Drugs Covered in This Chapter

Category Example

Topical ophthalmic anesthetics

• proparacaine hydrochloride• tetracaine hydrochloride

Diagnostic stain • fl uorescein

enipracolip •citoiM

Mydriatic • phenylephrine

Mydriatics/cycloplegics • atropine• homatropine• tropicamide• epinephrine

Prostaglandins • latanaprost• bimatoprost• travoprost

Carbonic anhydrase inhibitors

• acetazolamide (systemic)• dichlorphenamide (systemic)• methazolamide (systemic)• brinzolamide HCl (topical)• dorzolamide HCl (topical)

Beta-adrenergic blockers • timolol maleate• betaxolol• carteolol• levobunolol• metipranolol

Alpha-adrengeric agonists

• aproclonidine• brimonidine

Osmotic diuretics • mannitol• glycerin

Lacrimogenic • pilocarpine(Continued)



Category Example

Immunomodulators • cyclosporine• tacrolimus

Topical antibacterial ophthalmic drugs

• bacitracin• neomycin• polymyxin B• oxytetracycline• tetracycline• gentamicin• tobramycin• erythromycin• ciprofl oxacin• norfl oxacin• ofl oxacin• moxifl oxacin• chloramphenicol• sulfacetamide

Topical antifungal ophthalmic drugs

• natamycin• amphotericin B• povidone iodine• miconazole• itraconazole

Topical antiviral ophthalmic drugs

• idoxuridine• trifl uridine• vidarabine• acyclovir

Topical glucocorticoid ophthalmic drugs

• prednisolone acetate• prednisolone sodium phosphate• dexamethasone• triple antibiotic with hydrocortisone• neomycin with isofl upredone acetate• gentamicin with betamethasone• chloramphenicol with prednisolone• loteprednol etabonate• triple antibiotic with dexamethasone• sulfacetamide with prednisolone

Topical nonsteroidal anti-infl ammatory ophthalmic drug

• fl urbiprofen sodium• ketorolac tromethamine• diclofenac sodium• suprofen sodium• bromfenac• nepafenac

Tear supplement • artifi cial tears• lubricants




Table 18-5 Otic Drugs Covered in This Chapter

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Topical antibiotic otic drugs • gentamicin• neomycin sulfate• thiostreptin• chloramphenicol• enrofl oxacin

Topical antiparasitic otic drugs

• thiabendazole (neomycin/thiabendazole/ dexamethasone solution)

• pyrethrins• milbemycin oxime• ivermectin• selamectin

Topical otic antifungal agents

• clotrimazole• nystatin• miconazole• thiabendazole

Topical otic drying agents • salicylic acid• acetic acid• boric acid• tannic acid

Topical otic cleansing agents/local anesthetics

antibiotics, antiseptics (such as chlorhexidine and povidone iodine), and/or anesthetics/soothing agents (such as lidocaine) used to clean the ear

Topical otic dewaxing agents

cerumen softeners or drying agents containing chemicals such as benzyl alcohol, cerumene, and similar chemicals

Topical anti-infl ammatories • fl uocinolone plus DMSO• hydrocortisone

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Fundamentals of Pharmacology for Veterinary · PDF fileFundamentals of Pharmacology for Veterinary Technicians Chapter 18 Table 18-1 ... Fundamentals of Pharmacology for Veterinary