PHARMACOLOGY - Clinical (IOP, Steroids, Immunosuppressors etc) Flashcards
What are the most frequent side effects for prostaglandin analogues? (7)
- Increased iris pigmentation
- Iris cyst formation
- Increased peri-ocular skin pigmentation
- Eyelash hypertrichosis
- Iritis
- Peri-orbital fat atrophy
- CMO
What is ciclosporin’s main side effect?
nephrotoxicity, does not cause bone marrow suppression
- What are the main HIV medications?
- What are their main side effects?
- Ritonavir - nausea and diarrhoea
- Zidovudine - cytopaenia
- Zalcitabine - peripheral neuropathy
- Didanosine - pancreatitis
dida goalkeeper - brown - pancreatitis
zido/zico - is white - cytopaenia
Ribosomes are inhibited by which drug?
Chloramphenicol
What is the mechanism of action of fluoroquinolones?
Inhibit DNA replication by action on bacterial DNA gyrase
what is the mechanism of action of the imidazole antimicrobial?
inhibit cell membrane synthesis by inhibiting synthesis of sterols (important constiutent of fungal cell membranes)
What is the mechanism of action of aciclovir?
aciclovir inhibits DNA polymerase - an acyclic analogue of guanosine –>
works better in infected cells as it acts on thymidine kinase (active in infected cells)
Which drug can cause xanthopsia (yellow-blue discoloration), photopsia and pain on eye movements?
digoxin
What are the main side effects of carbonic anhydrase inhibitors (9) (-AMIDES)
- Paraesthesia
- Malaise complex (fatigue, weight loss)
- GI complex: diarrhoea, nausea, cramps due to potassium depletion
- Renal stone formation (calcium oxalate/phosphate)
- Steven-Johnson’s
- Bone marrow suppression/aplastic anaemia/agranulocytosis
- Thrombocytopaenia
- use in caution in patients with corneal endothelial dysfunction - affects endothelial pump mechanism
9, Teratogenic
What type of beta blocker is betoxalol? What is its protective effect?
Cardioselective (greater effect on B1 on myocardium vs B2 on respiratory/ocular system)
Protective effect on VF preservation due to effects on microperfusion of optic disc
What are the effects of betoxalol? (2)
Selective B1 blocker.
1. Less oculohypotensive effect than timolol
2. Greater effect on visual field preservation due to effects on microperfusion of optic disc
Which immunosuppressant has an enhanced effect with allopurinol?
azathioprine –> patients need reduced dose on this
What is the mechanism of action of apraclonidine?
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
What are the effects of apraclonidine? (3)
- Mydriasis
- Eyelid retraction
- Conjunctival blanching
What are the optic side effects of vigabatrin? (3)
- Optic Nerve Pallor
- RNFL atrophy
- Concentric peripheral field loss (binasal field defect with macula sparing- affects males more than females)
What is the mechanism of action of dorzolamide or brinzolamide?
carbonic anhydrase inhibitor
Which class of IOP lowering agents is most chemically similar to sulphonamides?
Carbonic anhydrase inhibitors
What drugs can cause corneal verticillata / vortex keratopathy? (5 + 1)
- Chloroquine
- Hydroxychloroquine
- Amiodarone
- Indomethacin
- Phenothiazines
- Fabry’s disease
What is the mechanism of action of prostaglandins?
Bimatoprost additionally does what?
Increase uveoscleral outflow –> increased aqueous outflow. Activated when hydrolysed by corneal esterase
Bimatoprost enhances trabecular outflow.
Which beta blocker will induce less bradycardia and postural hypotension than the others?
Carteolol - has intrinsic sympathetic activity.
What are the main complications of overtreatment with topical antivirals for HSK? (3)
- Follicular conjunctivitis
- Punctate keratitis with photophobia
- Sterile corneal ulceration
What is the main ocular side effects of brimonidine / apraclonidine?
After 1 year - allergic conjunctivitis, follicular conjunctivitis
What are the main side effects of topical prostaglandin analogues? (7)
- Increased iris pigmentation
- Iris cyst formation
- Increased peri-ocular skin pigmentation
- Peri-orbital fat atrophy
- Eyelash hypertrichosis
- Iritis
- CMO
Where are Beta-2 receptors found? (3)
Lungs, GI tract, vascular smooth muscle
Which antibiotics are known to be associated with IIH?
- Tetracyclines
- Fluoroquinolones
What drugs can induce optic neuropathy? (14)
Anti-Tb: Isoniazid, Ethambutol
Antibiotic: erythromycin, streptomycin, quinine, linezolid, dapsone (sulphonamide), chloramphenicol
Anti-retrovirals
Others: Amiodarone, Clioquinol, Infliximab, Pheniprazine, Suramin, Methotrexate
What are the ocular side effects of pilocarpine? (7)
- Miosis
- Induced myopia (myopic shift)
- Conjunctival vascular congestion
- Punctal stenosis
- Cataract formation
- Retinal detachment
- Headaches/brow ache
Which drugs should be avoided in myaesthenia gravis? (9)
- Aminoglycosides (gentamicin)
- Fluoroquinolones (ciprofloxacin, levofloxacin)
- Macrolides (erythromycin, azithromycin)
- Beta blockers
- Chlorpromazine
- Procainamide
- Penicillamine
- Respiratory supplements
Which topical steroid is least likely to induce intraocular pressure elevation?
Loteprednol etabonate
What are the ocular side effects of beta blockers?
(2)
What are the non ocular side effects of beta blockers?
(5)
- Reduced aqueous secretions by inhibition of beta-2 receptors on ciliary epithelium, punctate corneal erosions
- Local allergy, Bradycardia, Bronchospasm, Hypotension, Weakness (sleep disturbance, fatigue, headache, decreased libido)
What are the ocular side effects of topiramate? (8)
- Myopia
- Blurred vision
- Angle-closure glaucoma
- Scleritis
- Suprachoroidal effusion
- Periorbital Oedema
- Oculogyric crisis
- Blepharospasm
What are the side effects of acetazolamide? (7)
Biochemical (3)
Side effects (5)
hyponatraemia, hypokalaemia, metabolic acidosis
Renal calculi, paraesthesia of limbs, fatigue, Steven-Johnson’s syndrome, transient myopia
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?
Rituximab - anti-CD20 protein (B cell surface)
Cyclosporin/tacro - calcineurin inhibitor –> anti-IL2
Infliximab/atanercept - anti-TNFdi
What effects happen with beta-1 blockers? (3)
What effects happen with beta-2 blockers? (3)
beta -1
1. Slow pulse rate
2. Weakens myocardial contraction
3. Reduced exercise tolerance
beta - 2
1. Bronchoconstriction
2. Peripheral arterial constriction
3. Reduced aqeous production from ciliary epithelium
What are the main side effects of dorzolamide?
burning/blurring on instillation
bitter/metallic taste in mouth
Which drugs can induce a cataract? (8)
CATS have poor cataract eyes
- Chlorpromazine (phenothiazines)
- Amiodarone
- Topiramate + Tamoxifen
- Steroids
- Hydroxychloroquine
- Pilocarpine
- Cisplatin
- Epithelial toxins (busulphan, gold)
What effect does epinephrine have on intraocular pressure?
Reduces pressure
Which glaucoma medications increase uveoscleral outflow?
- Alpha-adrenergic agonists
- Prostaglandins
Which glaucoma medications decrease aqueous production? (3)
- Beta blockers (block adrenergic receptors ciliary body)
- Carbonic Anhydrase Inhibitors (inhibit enzyme in ciliary processes)
- Alpha-2 agonists (dual mechanism - increase uveoscleral outflow)
What is the mechanism of action of botox? What is it used to treat?
Binds to pre-synaptic Ca2+ mediated receptors on the nerve terminal (motor nerve) inhibiting ACh release
Cleaves SNARE proteins needed for fusion of neurosecretory vesicles with the plasma membrane and so block ACh exocytosis.
Used to treat Blepharospasm
Which drugs are generally avoided in uveitis related ocular hypertension? (2)
- Prostaglandins –> precipitate uveitic episode of CMO
- miotics –> increase vascular permeability and induce inflammation, worsen posterior synechiae
How do topical anaesthetics inhibit wound healing?
disrupt tight junctions between cells and interfere with corneal epithelial metabolism
What are the ocular manifestations of chloroquine use? (3)
- Corneal deposition
- Anterior subcapsular cataract
- Bull’s eye maculopathy
Which drug can cause xanthopsia (yellow-blue discoloration), photopsia and pain on eye movements?
digoxin
What are the main anti-inflammatory pathways of steroids (5)
- Inhibit enzymes for eicosanoid and phospholipase A2 synthesis
- Inhibit histamine release
- Inhibit numbers of PMLs, lymphocytes and macrophages
- Inhibit cytokine gene transcription in lymphocytes and Antigen-presenting complexes (APCs)
- Induce ACE and neuronal endopeptidases –> degradation of bradykinin, a vasoactive inflammatory mediator
- increase production of leukotrienes
What is the mechanism of action of edrophonium? What is it used for?
Reversible acetylinesterase inhibitor used in the tensilon test to test for myaesthenia gravis
What are the main side effects of ciclosporin? (5)
Nephrotoxicity
hepatotoxicity
gingival hyperplasia
hypertrichosis
hypertension
What drugs can cause optic neuropathies?
5 As
Antibiotics (chloramphenicol, sulphonamides)
Anti-TB (isoniazid, ethambutol)
Anti-malarials - hydroxychloroquine
Alcohol
All metals (lead, mercury)
What drug is used to aid diagnosis in Adie’s pupil?
Low dose pilocarpine (0.125%) constricts the abnormal dilated eye - there is supersensitive iris sphincter caused by loss of post-ganglionic nerve fibres.
Which pressure control drops have teratogenic side effects?
Which pressure control drops should be avoided when breastfeeding?
- Prostaglandins, carbonic anhydrase inhibitors and beta blockers - alpha-2 agonists are safe (apraclonidine, brimonidine)
- Alpha-2-agonists.
What are the main side effects of glucocorticoids / steroids? (4)
- Cataract (typically if 15mg daily prednisolone)
- Increased risk of bacterial infection
- Reactivation of viral keratitis
- Steroid induced IOP rise via GAG and water accumulation in the trabecular meshwork reducing outflow (30% are steroid responsive)
What are the risk factors to being a steroid responder? (5)
- All glaucoma except closed angle.
- High myope
- Corneal change: Fuch’s, keratoconus, keratoplasty
- T1DM
- FH of steroid response
What is the mechanism of action of ciclosporin A?
Caclineurin inhibitor and inhibits nuclear factor of activated T cells (NFAT) which leads to reduced production of IL-2
What is the mechanism of action of azathioprine?
What is it metabolised by?
What is it metabolised to?
purine antagonist/analogue which blocks RNA and DNA synthesis.
Azathioprine is metabolised by thiopurine methyltransferase
It is metabolised to 6-mercaptopurine
What is the mechanism of action of methotrexate?
Folic acid antagonist - inhibits dihydrofolate reductase to suppress DNA synthesis for both purines and pyrimidines
What are the side effects of azathioprine?
What are the side effects of methotrexate?
SAME: bone marrow suppression, hepatotoxicity (LFT monitoring)
DIFFERENCE:
Methotrexate: oral ulceration, myalgia, pneumonitis
What is the mechanism of action of cyclophosphamide?
Alkylating agent that cross-links between DNA strands to prevent transcription of mRNA
What is the mechanism of action of infliximab / etanercept
Anti-TNF alpha agents.
How do topical anaesthetics impair wound healing?
disrupt tight junctions between cells and interefore with corneal epithelial metabolism
What is the difference between unfractionated heparin and low-molecular weight heparin?
unfractionated heparin : potentiates anti-thrombin which inactivates thrombin and factor Xa –> inhibition of platelet aggregation
LMWH preferentially affects factor Xa.
What are the side effects of heparin ? (5)
- Bleeding
- Thrombocytopaenia (paradoxical thrombosis)
- Osteoporosis
- Hypoaldosteronism
- Hyperkalaemia
What drugs cause drug-induced myopia? (4)
HARRY ‘POTTA’
- Pilocarpine
- Oral contraceptive
- Tetracycline antidepressants
- Topiramate
- Acetazolamide
What drugs cause optic neuropathy? (8)
- Anti - TB : ethambutol, isoniazid
- Chloramphenicol
- hydroxycholorquine
- Amiodarone
- Cisplatin
- Vincristine
- Streptomycin
What drugs can cause raised intracranial pressure (drug-induced IIH)?
- Tetracycline
- Fluoroquinolones
- Retinoids (vitamin A)
- Progesterones
- Amiodarone
- Lithium
- Phenytoin
- Tamoxifen
What is the difference between the mechanism of action of 5-FU and MMC? Active stage?
5-FU : inhibits thymidylate synthetase in S phase/G2 cells –> inhibition of DNA synthesis. Active stage –> S Phase and G2
MMC: alkylating agent which cross links DNA. Active stage –> any stage
What are the adverse/side effects of 5-FU? (5)
- Corneal epithelium toxicity
- Hypotonous maculopathy
- Suprachoroidal haemorrhage
- Conjunctival wound leak
- Ischaemic blebs.
Acetazolamide is derived from…
sulphonamides so cannot be given to someone with sulphonamide allergy
What is the mechanism of action of carbonic anhydrase?
Carbonic anhydrase catalyses the reversible reaction H + HC03 –> H2C03. It stimulates aqueous production in non-pigmented ciliary epithelium by increasing availability of bicarbonate ions.
What is the mechanism of action of glucocorticoids?
How long does this process take?
Binds to cytoplasmic receptor proteins –> change in steroid rceptor complex to allow migration into nucleus –> binds to glucocorticoid response elements (GRE) on chromatin –> promoting transcription of specific mRNA and regulation of protein synthesis
Takes at least 30-60 minutes.
Why is apraclonidine contraindicated in children less than two?
Can pass blood brain barrier and cause CNS depression in children.
What type of IOP lowering drugs work on the…
1) trabecular meshwork
2) Uveoscleral pathway
3) Blockage of aqueous humor
ABC : reduce production of aqueous humour
APr: improve uveoscleral outflow (brimonidine)
PiR: Pilo –> contraction of ciliary body, Rho Kinase inhibitors improve trabecular outflow
What is the mechanism of action of mycophenolate mofetil?
Inhibits activity of inosine (de novo purine) monophosphate dehydrogenase (anti-metabolite M) to affect both T cells and B cells.
What are the side effects of cyclosporin? (6)
- Nephrotoxicity
- Hepatotoxicity
- Malignancy
- Hypertension
- Hyperkalaemia
- Thrombosis microangiopathy
What are the drugs that cause crystalline retinopathy? (4)
- Tamoxifen (fine yellow deposits)
- Nitrofurantoin (circinate pattern)
- Canthaxanthin
- Methoxyflurane (anaesthetic - calcium oxalate crystals)
Table which cause toxic optic neuropathy
What are the side effects of anti-cholinesterases?
- cyst proliferation of iris pigment epithelium at pupillary margin in children
- Cataracts in adults
Which anaesthetic can result in corneal epithelial toicity?
tetracaine
Which drug is a combined H1 blocker and mast cell stabiliser? (2)
- Opatanol
- Nedocromil
Which are the two main hyperosmotic drugs used in ophthalmology?
Mannitol and Glycerin
What is the order of potency of topical steroids (5)
- prednisolone acetate 1% (most potent)
- dexamethasone 0.1%
- betamethasone 0.1%
- prednisolone sodium phosphate 0.5%
- fluorometholone 0.1% (least potent)
Which ocular surface disease is linked to these tear film deficiencies:
1. Aqueous deficiency
2. Mucin deficiency
3. Lipid deficiency
- Aqueous - Sjogren’s syndrome
- Mucin - cicatriacal conjunctival disease and hyovitaminosis A
- Lipid - chronic meibomian gland inflammation
What is the difference in washout periods between pilocarpine, dorzolamide, timolol, brimonidine and latanoprost?
pilocarpine - 3 days
dorzolamide - 7 days
timolol - 4 weeks
brimonidine - 5 weeks
latanoprost - 8 weeks
What is the mechanism of action of tolicizumab?
Monoclonal antibody against IL-6 receptor - used for treatment against RA, refactory GCA and rare uveitis.
Which drug causes of binasal visual field defect?
Vigabatrin
What are the ocular manifestations of amantidine?
Corneal infiltrate, corneal oedema
Which drug is used to treat filamentous fungal infections of the eye?
Which drug is used to treat Yeast fungal infections of the eye?
Filamentous: Natamycin
Yeast: Amphotericin
Which anti-parkinsonian medications is associated with acute angle closure and dry eyes?
Benztropine - anti-cholinergic
What are the guidelines for screening for no risk factor patients on hydroxychloroquine?
What are the guidelines for screening for risk factor patients on hydroxycholoroquine?
What are the risk factors? (4)
No risk factors: annual screening after 5 yrs
Risk factors: annual screening after 1 year
Risk factors:
1. Tamoxifen use
2. Chloroquine use
3. Hydroxychoroquine >5mg/kg/day
4. Impaired kidney function
What dose of atropine is required to reverse the Tensilon test for MG?
0.5mg
What type of anaesthetic is lidocaine?
Amide
Is lidocaine supplied in its protonated form or unprotonated form? What happens when exposed to human tissue at pH7.4?
Supplied in unprotonated form –> becomes protonated in human tissues.
Whcih anaesthetics are from the ester class? What are they typically used for?
- Tetracaine
- Benoxinate (Oxy)
- Proparacaine
Typically used topically.
What are the mechanism of action of the TB drugs?
What is their side effects?
Rifampicin
Mechanism: inhibits RNA polymerase
Side effects: Hepatotoxicity, changes bodily fluids orange.
Isoniazid
Mechanism: Inhibits cell wll synthesis of mycobacteria
Side effects: B6 deficiency (supply with pyridoxine) optic neuropathy
Pyrazinamide
Ethambutol
Mechanism: Chelating agent
Side effects: Optic neuropathy
Which structures contain cholinergic receptors?
Iris
Ciliary Body
Corneal epithelium
What are the contraindications for keratoconus cross linking (5)
- Corneal thickness < 400
- Previous herpetic infection
- Severe corneal scarring
- Poor ocular surface
- Autoimmune disorders
What is the safe timeframe for steroid-induced IOP? When is it reversible/permanent?
< 5 days - never
< 2 weeks - very low risk
< 1 year - reversible
> 18 months - permanent
Which immunosuppressive drug is safest to use in females of child-bearing age?
Azathioprine.
What beta blockers are cardioselective?
Block Beta - 1
BAM
Betaxolol
Atenolol
Metoprolol
What are the side effects of adalimumab?
Drug-induced lupus
MS
Skin cancer (BCC, SCC)
TB reactivation