Eyedocs pharmacology Flashcards

1
Q

What are the actions of the parasympathetic pathway? (4)

A
  1. Ciliary muscle contaction –> accomodation
  2. Sphincter muscle constriction –> dilation
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2
Q

What are the actions of the sympathetic pathway?

A
  1. Ciliary muscle relaxation
  2. Sphincter pupillae action –> pupil miosis
  3. Upper lid retraction (Dalrymple sign)
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3
Q

What neurotransmitter is secreted in the sympathetic pathway?

A

Acetylcholine

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4
Q

What are the mechanism of pilocarpine? (6)

A

sympathetic agonist - acts on muscarinic / Ach receptor

  1. Iris sphincter contraction - pupil miosis
  2. Ciliary muscle contraction - accomodative spasm (can treat accomodative esotropia by reducing drive for convergence)
  3. Ciliary muscle contraction –> lens thickening and move forward –> iris moving forward –> narrow anterior chamber angle –> COAG
  4. Ciliary muscle contraction –> increases tension on scleral spur –> opening of trabecular meshwork (conventional route) –> reduce IOP
  5. Ciliary muscle contraction –> myopia
    6 –> increased vascular permeability (should be avoided in uveitis)
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5
Q

Which drugs can reverse atropine mydriasis?

Which drugs can reverse phenylephrine mydriasis?

A
  1. Pilocarpine
  2. Pilocarpine, thymoxamine (more effective)
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6
Q

Which HIV drugs are reverse transcriptase inhibitors?

Which HIV drugs are protease inhibitors?

A

Didanosine, Zidovudine, Zalcitabine

Ritonavir

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7
Q

What are the main side effects of carbonic anhydrase inhibitors (6)

A
  1. Paraesthesia
  2. Malaise complex (fatigue, weight loss)
  3. GI complex: diarrhoea, nausea, cramps
  4. Renal stone formation (calcium oxalate/phosphate)
  5. Steven-Johnson’s
  6. Bone marrow suppression/aplastic anaemia
  7. use in caution in patients with corneal endothelial dysfunction - affects endothelial pump mechanism
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8
Q

What type of beta blocker is betoxalol? What is its protective effect?

A

Cardioselective (greater effect on B1 on myocardium vbs B2 on respiratory/ocular system)

Protective effect on VF preservation due to effects on microperfusion of optic disc

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9
Q

What are the effects of betoxalol? (2)

A
  1. Less oculohypotensive effect than timolol
  2. Greater effect on visual field preservation due to effects on microperfusion of optic disc
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10
Q

Which immunosuppressant has an enhanced effect with allopurinol?

A

azathioprine –> patients need reduced dose on this

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11
Q

What is the mechanism of action of botox?

A

inhibition of release of ACh from presynaptic nerve terminals

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12
Q

What is the mechanism of action of apraclonidine?

A

alpha-2-adrenergic agonist (partial) –> potent systemic anti-hypertensive –> causes mydriasis

Acts on the presynaptic nerve endings and are inhibitory –> prevent further release of neurotransmitter

Has very little alpha-1 activity

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13
Q

What are the effects of apraclonidine? (3)

A
  1. Mydriasis
  2. Eyelid retraction
  3. Conjunctival blanching
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14
Q

What are the optic side effects of vigabatrin? (3)

A
  1. Optic Nerve Pallor
  2. RNFL atrophy
  3. Concentric peripheral field loss (binasal field defect with macula sparing)
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15
Q

What is the mechanism of action of dorzolamide or brinzolamide?

A
  1. Transient bitter taste
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16
Q

What compounds are most likely to penetrate the cornea to reach the anterior chamber (ie biphasic - both hydrophilic and hydrophobic) (3)

A
  1. Acetate (most)
  2. Alcohol
  3. Phosphate (least)
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17
Q

Which class of IOP lowering agents is most chemically similar to sulphonamides?

A

Carbonic anhydrase inhibitors

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18
Q

What drugs can cause corneal verticillata / vortex keratopathy? (5 + 1)

A
  1. Chloroquine
  2. Hydroxychloroquine
  3. Amiodarone
  4. Indomethacin
  5. Phenothiazines
  6. Fabry’s disease
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19
Q

What is the mechanism of action of prostaglandins?

A

Increase uveoscleral outflow –> increased aqueous outflow.

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20
Q

Which beta blocker will induce less bradycardia and postural hypotension than the others?

A

Carteolol - has intrinsic sympathetic activity.

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21
Q

What are the main complications of overtreatment with topical antivirals for HSK? (3)

A
  1. Follicular conjunctivitis
  2. Punctate keratitis with photophobia
  3. Sterile corneal ulceration
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22
Q

What is the main ocular side effects of brimonidine / apraclonidine?

A

After 1 year - allergic conjunctivitis, follicular conjunctivitis

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23
Q

What are the main side effects of topical prostaglandin analogues? (7)

A
  1. Increased iris pigmentation
  2. Iris cyst formation
  3. Increased peri-ocular skin pigmentation
  4. Peri-orbital fat atrophy
  5. Eyelash hypertrichosis
  6. Iritis
  7. CMO
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24
Q

What is the mechanism of action of quinolones?

A

ciprofloxacin

Blocks DNA synthesis by inhibiting DNA gyrase

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25
Q

Which antibiotics inhibit bacterial cell wall synthesis? (3)

A

Penicillins, cephalosporins (ceftriaxone), vancomycin

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26
Q

Where are Beta-2 receptors found? (3)

A

Lungs, GI tract, vascular smooth muscle

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27
Q

What is the systemic effect of leukotrienes? (3)

A
  1. Bronchoconstriction
  2. Vasoconstriction
  3. Increase vascular permeability
    –> involved in allergic reactions and inflammation
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28
Q

What drugs can induce optic neuropathy? (14)

A

Anti-Tb: Isoniazid, Ethambutol
Antibiotic: erythromycin, streptomycin, quinine, linezolid, dapsone (sulphonamide), chloramphenicol
Anti-retrovirals
Others: Amiodarine, Clioquinol, Infliximab, Pheniprazine, Suramin

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29
Q

Systemically, what can chloramphenicol cause?

A

aplastic anaemia

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30
Q

What are the ocular side effects of pilocarpine? (7)

A
  1. Miosis
  2. Induced myopia (myopic shift)
  3. Conjunctival vascular congstion
  4. Punctal stenosis
  5. Cataract formation
  6. Retinal detachment
  7. Headaches/brow ache
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31
Q

Which drugs should be avoided in myaesthenia gravis? (9)

A
  1. Aminoglycosides (gentamicin)
  2. Fluoroquinolones (ciprofloxacin, levofloxacin)
  3. Macrolides (erythromycin, azithromycin)
  4. Beta blockers
  5. Chlorpromazine
  6. Procainamide
  7. Penicillamine
  8. Respiratory supplements
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32
Q

Which topical steroid is least likely to induce intraocular pressure elevation?

A

Loteprednol etabonate

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33
Q

Which antibiotics inhibit protein synthesis? (5)

Which antibiotics inhibit 30S subunit

Which antibiotics inhibit 50S subunit

A

30S: tetracycline, aminoglycosides (messenger RNA)
50S: Macrolides, Lincosamides, Chloramphenicol

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34
Q

What antibiotics inhibit cell wall synthesis?

A

Beta lactam antibiotics - penicillin, cephalosporins

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35
Q

What antibiotics inhibit folic acid synthesis?

A

Sulphonamides
Trimethoprim

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36
Q

What antibiotics inhibit DNA gyrase and transcription?

A

Fluoroquinolones

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37
Q

What are the ocular effects of tamoxifen? (3)

A
  1. White retinal crystals
  2. Retinal lesions
  3. Macula oedema
38
Q

What is the mechanism of action of aciclovir?

A

Inhibits DNA polymerase

39
Q

What is Fick’s Law?

A

rate of diffusion = diffusion coefficient x concentration gradient / membrane thickness

40
Q

What are the ocular side effects of beta blockers?
(2)
What are the non ocular side effects of beta blockers?
(5)

A
  1. Reduced aqueous secretions by inhibition of beta-2 receptors on ciliary epithelium, punctate corneal erosions
  2. Local allergy, Bradycardia, Bronchospasm, Hypotension, Weakness (sleep disturbance, fatigue, headache, decreased libido)
41
Q

Which antibiotic is the most retino-toxic when given intravitreally?

A

Gentamicin (gram negative cover)

42
Q

What are the ocular side effects of topiramate? (5)

A
  1. Myopia
  2. Blurred vision
  3. Angle-closure glaucoma
  4. Scleritis
  5. Suprachoroidal effusion
43
Q

What is the mechanism of action of azathioprine / methotrexate?

A

Inhibit purine ring biosynthesis - cytotoxic anti-metabolite

44
Q

What are aminoglycosides not effective against?

A

Streptococcus and strict anaerobes

45
Q

What is the general actions of adrenergic agonists (4)

A
  1. Increase aqueous outflow
  2. Ciliary muscle relaxation
  3. Contraction of Muller’s muscle –> ptosis relief
  4. Conjunctival vessel constriction
46
Q

Which drugs are alpha-1 adrenergic agonists?

Which drugs are alpha-2 adrenergic agonists?

A

Alpha-1 : phenylephrine
Alpha-2: aproclonidine

47
Q

What are the side effects of acetazolamide? (7)
Biochemical (3)
Side effects (4)

A

hyponatraemia, hypokalaemia, metabolic acidosis

Renal calculi, paraesthesia of limbs, fatigue, Steven-Johnson’s syndrome

48
Q

What is the mechanism of action of rituximab?
What is the mechanism of action of cyclosporin or tacrolimus?
What is the mechanism of action of infliximab and etanercept?

A

Rituximab - anti-CD20 protein (B cell surface)
Cyclosporin/tacro - anti-IL2
Infliximab/atanercept - anti-TNF

49
Q

Which drug can cause xanthopsia (yellow-blue discoloration), photopsia and pain on eye movements?

A

digoxin

50
Q

Which antibiotics are known to be associated with IIH?

A
  1. Tetracyclines
  2. Fluoroquinolones
51
Q

What factors affect diffusion coefficient? (3)

A
  1. Lipid solubility
  2. Ionization
  3. Molecular size
52
Q

What happens to drug absorption with increased blink rate?

A

Reduces by increasing clearance

53
Q

What effect does acidity/alkaninity have on a drug?

A
  1. More unionised and so more lipid soluble to increase corneal absorption
  2. Causes irritation/lacrimation –> drug clearance
54
Q

What is the mechanism of action of cocaine?

A

inhibits reuptake of monoamines at the synaptic space

55
Q

What effect do steroids have on trabecular meshwork?

A

increase production of myocilin

56
Q

What does Phase 1 drug metabolism involve?

A

oxidation reactions (carried out by cytochrome P450)

57
Q

What do Phase 2 drug metabolism involve?

A

conjugation reactions (addition of glucuronate, glutamine and acetate groups) which makes molecules more water soluble for excretion

58
Q

What type of drug is etanercept?

A

anti-TNF alpha drug

59
Q

What is the mechanism of action of methotrexate?

A

Folate antagonist

60
Q

What is the mechanism of action of azathioprine?

A

Purine analogue

61
Q

What is the mechanism of action of ciclosporin?

A

IL-2 inhibitor (T-cell inhibitor)

62
Q

what is the mechanism of action of imidazole antifungals?

A

inhibitr cell membrane synthesis - they inhibit the synthesis of sterols which are an important constituent in fungal cell membranes (anti-mycotics)

63
Q

Which drug relaxes the ciliary body?

A

atropine

64
Q

What are the main risk factors for steroid-induced raised IOP? (6)

A
  1. POAG
  2. Pigmentary glaucoma
  3. FH of glaucoma
  4. High myopes
  5. Diabetics
  6. FH of steroid responders
65
Q

Which glaucoma drug is safest in pregnancy?

A

alpha-2 agonists (brimonidine, apraclonidine)

66
Q

Which drugs can cause a drug-induce myaesthenia? (6)

A
  1. NJ blockers - suxamethonium
  2. Resp suppressors - morphine
  3. Aminoglycosides
  4. Chloropromazine
  5. Procainamide
  6. Penicillamine
67
Q

Accomodation occurs with parasympathetic or sympathetic control?

A

parasympathetic control

68
Q

Which drugs are parasympathetic antagonists?

A
  1. Cyclopentolate
  2. Tropicamide
  3. Atropine
  4. Phenothiazine
69
Q

Which drugs are generally avoided in uveitis related ocular hypertension? (2)

A
  1. Prostaglandins –> precipitate uveitic episode of CMO
  2. miotics –> increase vascular permeability and induce inflammation, worsen posterior synechiae
70
Q

What are the ocular side effects of topiramate (6)

A
  1. AACG
  2. Oculogyric crises
  3. Periorbital oedema
  4. Scleritis
  5. Acute myopia
  6. Blepharospasm
71
Q

What is the mechanism of action of botox/

A

Binds to pre-synaptic receptors on the nerve terminal (motor nerve) inhibiting ACh release

72
Q

Which glaucoma medications decrease aqueous production?

A
  1. Beta blockers
  2. Carbonic Anhydrase Inhibitors
  3. Alpha-2 agonists (dual mechanism)
73
Q

Which glaucoma medications increase uveoscleral outflow?

A
  1. Alpha-adrenergic agonists
  2. Prostaglandins
74
Q

What ocular side effect occurs with prolonged use of ciprofloxacin?

A

Corneal crystalline precipitates

75
Q

What effect does epinephrine have on intraocular pressure?

A

Reduces pressure

76
Q

Which drugs can induce a cataract? (6)

A
  1. Chlorpromazine (anterior lens capsule)
  2. Corticosteroids
  3. Allopurinol
  4. Amiodarone
  5. Busulphan
  6. Gold (anterior capsule deposits)
77
Q

What type of bacteria do tetracyclines target? (3)

A

Gram +ve
Gram -ve
Chlamydia

78
Q

What is the mechanism of action of phenylephrine?

A

Non selective alpha agonist

79
Q

What are the main side effects of dorzolamide?

A

burning/blurring on instillation
bitter/metallic taste in mouth

80
Q

What effects happen with beta-1 blockers? (3)

A
  1. Slow pulse rate
  2. Weakens myocardial contraction
  3. Reduced exercise tolerance
81
Q

What effects happen with beta-2 blockers?

A
  1. Bronchoconstriction
  2. Peripheral arterial constriction
  3. Reduced aqeous production from ciliary epithelium
82
Q

What is the difference between lipid soluble and water soluble drugs? (3)

A
  1. Lipid soluble enter BBB so have more CNS effects
  2. Water soluble are easier to clear
  3. Hepatic drug metabolism converts lipid soluble drug into a water soluble drug
83
Q

What is the mechanism of action of tropicamide?

A

It is a muscarinic antagonist - blocks parasympathetic pathway.

84
Q

what are the side effects of tropicamide?

A
  1. precipitates angle closure
  2. exacerbates ataxic dysarthia
  3. cerebellar signs
  4. increases risk of seizure
85
Q

Which drug can be used for infections caused by aspergillus and candida?

A

Topical amphotericin

86
Q

In what instances are alpha-2-agonists contraindicated? (2)

A
  1. Potentiates hypertensive crisis with monoamine oxidase inhibitors
  2. WIth TCAs, its IOP effect is removed.
87
Q

What are the most important factors on rate and extent of ocular absorption (5)

A

PRE-corneal factors
1. Tear volume (7-30ul)
2. Tear turnover time (-.5-2.2ul/min)
3. Blink rate (15-min)

all these factors limit drug time in conjunctival sac to 3-5 minutes on average

  1. Corneal thickness
  2. Conjunctival:corneal surface area (17:1)
88
Q

What is the greatest barrier in the cornea for ocular drug penetration?

What route does it go by?

A

Corneal epithelium (lipophilic layer)

Lipophilic drugs –> intracellular route
Hydrophilic drugs –> paracellular route

89
Q

Which drugs accumulate in the cornea? (2)

A
  1. NSAIDs
  2. Pilocarpine
90
Q

What is the effect of muscarinic agonists, example? (3)

A

Direct - pilocarpine
Indirect - carbachol - inhibits cholinesterase

  1. Miosis
  2. Accomodation
  3. Decreased intraocular pressure
91
Q

What are the main muscarinic agonists and antagonists?

A

Musacrinic agonist - pilocarpine, carbahol

Muscarinic antagonist - atropine

92
Q

What is the order of potency for muscarinic antagonists?

A

atropine > cyclopentolate > homatropine > tropicamide