Pharmacology Flashcards by Elizabeth Orpwood

Is the corneal epithelium hydrophilic or lipophilic?

Which means water soluble drugs or lipid soluble drugs cross more easily?

Lipophilic

Lipid soluble drugs cross more easily

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Is the corneal endothelium hydrophilic or lipophilic?

Which means water soluble drugs or lipid soluble drugs cross more easily?

Lipophilic

Lipid soluble drugs cross more easily

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Is the corneal stroma hydrophilic or lipophilic?

Which means water soluble drugs or lipid soluble drugs cross more easily?

Hydrophilic

Water soluble drugs cross more easily

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Unpreserved eye drops should be used for less than how many days

What temperature?

<7days

2-8’C

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Are ionised or non ionised eye drops hydrophilic?

Ionised

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Are ionised or non ionised eye drops lipophilic?

Non ionised

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What can be added to eye drops to improve penetration (2)?

Organic salts (eg. Prednisolone acetate)

Preservatives (eg. Benzalkonium chloride or thimersol)

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What pH do eye drops need to be between to be comfortable?

Size?

pH 4.5-9

10mum

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Do hydrophilic or lipophilic drugs penetrate the sclera better?

Anionic or cationic drugs?

Hydrophilic

Anionic

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Does systemic amoxycillin clavulanic acid have good or bad ocular penetration in the non inflamed eye? Inflamed eye?

Are they good at gram positive or gram negative bacteria?
Bacteriostatic or bacteriocidal?

What does it target?

Poor in the non inflamed eye, ok in the inflamed eye

Gram positive

Bacteriocidal

Cell wall synthesis

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First generation cephalosporins (cephalexin and cefazolin) are good against gram positive or gram negative bacteria?

Bacteriostatic or bacteriocidal?

What is cefazolin useful for?

What does it target?

Gram positive

Bacteriocidal

IV administration, good intraocular penetration. Prophylactic for phaco

Cell wall synthesis

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Second generation cephalosporin has gram positive or gram negative action?

Cefuroxime is an example, what is this useful for?

Both!

Phaco

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Is bacitracin bacteriocidal or bacteriostatic?

Gram positive or gram negative?

Target?

Use in ophtho?

Corneal penetration?

Bacteriocidal

Gram positive

Cell wall synthesis

Superficial bacterial keratitis

Little to no corneal penetration

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Which bacteria is vancomycin effective against?

Gram positive or gram negative?

Bacteriostatic or bacteriocidal?

MRSA

Gram positive

Bacteriocidal

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What does polymixin in B target?

Gram positive or gram negative?

Bacteriostatic or bacteriocidal?

Which bacteria is it good against?

Good penetration in the corneal epithelium?

Cell membrane

Gram negative

Bacteriocidal

Pseudomonas aeruginosa

Poor!

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Gramcidin

Target?

Gram positive or gram negative?

Bacteriostatic or bacteriocidal?

Why shouldn’t it be used systemically?
Which bacteria is it good against?

Cell membrane

Gram positive

Bacteriocidal

Causes haemolytic anaemia

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Aminoglycosides

Target?

Gram positive or gram negative?

Bacteriostatic or bacteriocidal?

How should it be given?

Inhibit Bacterial protein synthesis

Gram negative (some gram positive)

Bacteriocidal

Parenterally or topically, poor oral absorption

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Neomycin

What type of drug?

Which bacteria is it good against?
Not good against?

Good penetration in the cornea?

Topical aminoglycoside

Good against pseudomonas
Not good against beta haemolytic streptococcus

Bad corneal penetration?

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What type of drug is gentamicin?

What does it do if injected Intravitreally?

Use?

Aminoglycoside

Destroys ciliary body and retina

End stage glaucoma

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What is tobramycin good against?

How is it used?

What type of drug is it?

Pseudomonas

Topically

Aminoglycoside

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Tetracyclines

Bacteriostatic or bacteriocidal?

What infections are they good for?

What conditions are they indicated in?

Bacteriostatic

Rickettsial infections

Indolent ulcers
Keratomalacia

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What do tetracyclines inhibit?

Where can doxycycline reach after oral dosing?

What side effects in young animals can doxy cause?

Other side effects?

Matrix metalloproteinase

Tear film

Discolouration of teeth

GI
Photosensitivity reactions

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Macrolides and Lincosamides

Target?

Gram positive or gram negative?

Bacteriostatic or bacteriocidal?

Inhibiting bacterial protein synthesis

Gram negative and mycoplasma, chlamydophila, Bartonella

Bacteriostatic

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What type of drugs are erythromycin, azithromycin, clarithromycin?

Macrolides and lincosamides

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Clindamycin is what type of drug? What is it good against?

Macrolides and lincosamides Toxoplasma gondii

Chloramphenicol Target? Gram positive or gram negative? Bacteriostatic or bacteriocidal? If used systemically what can it cause?

Inhibits protein synthesis Gram positive and negative Bacteriostatic Haematopoietic disorders and aplastic anaemia (even months after stopping)

Does choramphenicol ointment or drops reach a higher corneal and aqueous humour drug concentration?

Ointment

Fluoroquinolones Target? Gram positive or gram negative? Bacteriostatic or bacteriocidal?

DNA synthesis Both Bacteriocidal

Which fluoroquinolone can cause retinal degeneration in cats?

Enrofloxacin

Does ciprofloxacin or ofloxacin have better aqueous penetration?

Ofloxacin

Are most antifungals fungistatic or fungicidal? Where do they normally target?

Fungistatic Fungal cell wall

What side effects does amphotericin B cause if given IV? Good penetration through the corneal epithelium? What is it used for?

Renal, hepatic and haematological side effects Poor Ulcerative fungal keratitis

Natamycin has a good or poor corneal penetration?

Poor

What can ketoconazole cause (side effect)?

Hepatic toxicity | Cataractogenesis

Do triazole antifungals have good penetration in the cornea/ aqueous etc? Orally?

Yes Yes

What side effects can voriconazole cause in cats? What class of antifungal is it?

Inappetence Lethargy Neuro signs Azotaemia Triazole

Does topical echinocandins (caspofungin and micafungin) have good or poor intraocular penetration?

Poor

Does aciclovir have good efficacy in cats? What are the side effects?

No Bone marrow suppression Hepatic and renal necrosis

Does penciclovir have good efficacy in cats?

Good in vitro!

What treatment is used for E cuniculi in rabbits?

Fenbendazole 20mg/kg for 4weeks

What is the treatment of angiostrongylus vasorum (2)?

Moxidectin | Fenbendazole

What is the treatment of leishmania in dogs?

Sodium stibogluconate +/- allopurinol

What is the treatment of thelzia callipaeda and T californiensis in dogs? What does it cause?

Imadoclopride 10% and moxidectin 2.5% (advocate) Conjunctivitis Dacryocystitis

Where do corticosteroids target?

What topical steroid is the most efficacious anti inflammatory agent for the anterior segment?

1% prednisolone acetate

How do corticosteroids promote keratomalacia?

Lytic activity of collagenases

Corticosteroids reduce migration of what and reduce phagocytosis of pathogens by what?

Leukocytes | Macrophages

Where is Cox 1 expressed? Use?

Endoplasmic reticulum of cells Normal tissue homeostasis

Where is Cox 2 expressed? What causes it to be expressed?

Inflamed tissue Cytokines

Do topical NSAIDs inhibit or enhance corneal vascularisation? Increase or decrease IOP? Do topical NSAIDs delay corneal re epithelialisation? Stromal healing?

Inhibit corneal vascularisation Increase IOP Delay corneal re epithelialisation but not stromal healing

What does cyclosporin do?

Inhibits calcineurin, which blocks the production of IL-2 and the activation of T cells

What are the side effects of azothioprine? Does it affect B or T lymphocytes?

GI signs Hepatotoxicity Pancreatitis Bone marrow suppression Both (more T)

What has oral megoestrol acetate been used for?

Feline eosinophilic keratoconjunctivitis

What receptors do prostaglandin analogues work on? Where are these receptors? How do they work?

F prostanoid Uveal tract and trabecular network Increase uveoscleral outflow

What are the side effects with prostaglandin analogues? What cases are they contraindicated in?

Conjunctival hyperaemia Miosis Anterior lens luxation

Concurrent use of topical anti inflammatories with prostaglandin analogues does what to the IOP lowering effect?

Decreases it

How do carbonic anhydrase inhibitors work?

Reduce aqueous production by limiting production of bicarbonate ions in the non pigmented ciliary epithelium and therefore the associated active secretion of sodium ions and water in to the posterior chamber

Which one is effective at lowering iop in NON glaucomatous eyes in dogs/ cats/ both? Dorzolamide (trusopt) Brinzolamide (azopt) Which is better for glaucomatous cats? Why?

Dorzolamide - dogs and cats Brinzolamide - just dogs (works in glaucomatous cats) Brinzolamide - reduced ocular irritation, pH 7.5 whereas Dorzolamide pH 5.6

What are the side effects of systemic carbonic anhydrase inhibitors?

Electrolyte disturbances | Inappetance/ V+/ lethargy - cats

What do beta blockers do, 3 mechanisms?

Reduce aqueous production; - Blocking beta receptors on ciliary epithelium, inducing a decrease in cAMP levels and therefore reduction in secretory function - blocking sodium ATPase, reducing active transport and aqueous production - modulation of ciliary body blood flow

What patients should beta blockers be avoided in? What are the side effects?

Cardiovascular or pulmonary disease Bradycardia Hypotension Bronchoconstriction Miosis

How does pilocarpine work in glaucomatous eyes? Which cases of glaucoma has it been proven to work in?

Increases conventional aqueous outflow Primary angle glaucoma in beagles

How often should beta blockers be used in glaucomatous eyes?

Every 8-12hours

What is the side effect of pilocarpine?

Constricts pupil | Low pH cause ocular irritation

How do alpha 2 adrenergic agonists work in glaucoma? Use in dogs/ cats?

Reduction of aqueous production Increase uveoscleral outflow Not in cats Can use in cats but not in narrow angle glaucoma as it causes mydriasis which may compromise outflow more!

What dose of IV mannitol should be used in emergency glaucoma? How long does this take to work? How long does it last for? What can cause this to work less? What can enhance osmotic diuretic to work?

0.5-2g/kg IV over 30mins Takes 1h to work, lasts for 24h Uveitis- blood ocular barrier breakdown Withholding water for 2-4h after administration

What dose of oral glycerol should be used? How long does it take to work? How long does it last for? What condition shouldn’t this be used in?

1-2g/kg Takes 1h to work Lasts 10h Diabetics- it is metabolised to glucose

What does cycloplegic mean?

Paralyse ciliary body musculature

What type of drugs are tropicamide and atropine? How do these work?

Anticholinergic agents Reversibly Blocking cholinergic receptors in the iris sphincter muscle causing pupil dilation

How long does tropicamide 0.5-1% take to work? How long does it last for? How does it affect IOP? Tear production?

10-20mins 6-8hours Increase IOP Doesn’t reduce tear production in dogs but will in cats

Atropine 1% How long does it take to work? How long does it last for? How does it affect IOP? Tear production?

40mins 3-14days Increase IOP Reduces tear production

Cyclopentolate 1% What type of drug? What side effects?

Anticholinergic agent Chemosis in dogs

What type of drugs are Phenylephrine and Adrenaline?

Sympathomimetics

How can Phenylephrine be used to distinguish between conjunctival hyperaemia and episcleral hyperaemia?

Conjunctival hyperaemia- blanched quickly, few seconds Episcleral hyperaemia- blanches more slowly 1-2mins

How can adrenaline be used in the eye?

Ineffective topically | Can use intracamerally (intraocular surgery for mydriasis and haemostasis

How do local anaesthetics work?

Reversibly block nerve depolarisation by inhibiting axonal sodium ion influx

How long does proxymetacaine take to work? How long does it last? Peak effect?

1min 45mins 15mins

How long does lignocaine 1% last? How long does bupivacaine 0.5% last?

45-60mins 5-10hours

What type of viscous agents are viscotears/ lubrithal/ optixcare? Advantage?

Carbomer polymer Last longer

What is the disadvantage of hypromellose?

Doesn’t last long

What benefits does sodium hyaluronate based tear replacements have over others?

Improve corneal epithelial cell migration

What does cyclosporin and tacrolimus block?

Production of IL-2 and activation of T cells

How can cyclosporin help with qualitative dry eye? What else can it do?

It is also mucinomimetic Reduce corneal pigment/ angiogenesis

What does tissue plasminogen factor do? How is it administered?

Coverts plasminogen to plasmin in the presence of fibrin. Fibrinolysis Intracameral or Intravitreal

What type of drug is mitomycin C? What can it be used for? How is it administered?

Anti fibrotic Glaucoma implants Squamous cell carcinoma along with keratectomy Soaked sponge