Lecture 11 Medical management of glaucoma part 2-OBB's/A2A's/CAI's/cholinergics Flashcards
Which OBB (ocular beta blocker) medication was FDA approved in 1978 which changed how glaucoma was managed?
a) propranolol
b) practolol
c) timolol
d) metoprolol
c) timolol. (Propranolol was developed in 1964 to treat systemic hypertension and angina, as an OBB, however, it anesthetized the cornea. Practolol was developed which did not anesthetize the cornea but caused immunological problems such as occulomucocuataneous syndrome. Metoprolol is a current oral beta blocker therapy)
(T/F) Beta blockers became the primary therapy for glaucoma after the FDA approval of timolol and up until 1996 when the prostaglandin analog called latanoprost showed to be more effective.
true
*Match the following regarding beta blockers:
1) beta-1
2) beta-2
3) beta-3
a) receptors found in bronchial muscle, blood vessels, and uterus
b) receptors found in mammals for mediation of lipolysis
c) receptors found in heart
1) beta-1–c) receptors found in heart
2) beta-2–a) receptors found in bronchial muscle, blood vessels, and uterus
3) beta-3–b) receptors found in mammals for mediation of lipolysis
*think beta-1=heart b/c you have 1 heart, beta-2=lungs b/c you have 2 lungs
Which one of the following statements regarding beta-blockers is FALSE?
a) stimulation of beta-1 receptors causes bradycardia (decreased heart rate) and decreased cardiac contractility
b) stimulation of beta-2 receptors causes dilation of bronchi and blood vessels
c) beta-3 has recently been identified in mammals for mediation of lipolysis
d) all of the above are true
a) stimulation of beta-1 receptors causes bradycardia (decreased heart rate) and decreased cardiac contractility. (FALSE–stimulation of beta-1 causes tachycardia (increased heart rate) and increased cardiac contractility.
(T/F) Ocular beta blockers (OBB’s) are also known as beta-adrenoreceptor agonists
false— OBB’s are aka beta-adrenoreceptor ANTAGONISTS (they block the receptor, an agonist would aid in the stimulation of the receptor)
(T/F) OBB’s are “competitive” inhibitors
true
(T/F) A non-selective OBB would effect BOTH beta-1 and beta-2, whereas, a selective OBB would effect EITHER beta-1 or beta-2.
true–keep in mind a high enough dose of a selective beta blocker could affect both beta-1 and beta-2
- How do OBB’s reduce IOP (what is the mechanism of action)?
a) decrease aqueous production
b) increase aqueous outflow through the trabecular pathway only
c) increase aqueous outflow through the uveoscleral pathway only
d) OBB’s help with both aqueous production and outflow
a) decrease aqueous production (by as much as 50%)–there is no effect on aqueous outflow.
(T/F) The mechanism by which OBB’s reduce aqueous production is still not clear, however, there are 2 hypothesis’s: classic and alternative hypothesis.
true.
1) Classic= OBB’s, through a cascade of events, eventually block cAMP which is required to produce aqueous.
2) Alternative=OBB’s interfere with the tonic stimulation needed to produce aqueous.
*Keep in mind there is evidence against the CLASSIC hypothesis, some studies have shown IOP to decrease in response to cAMP and regarding the ALTERNATIVE, this is just speculation.
Which one of the following is NOT an indication for OBB’s?
a) ocular hypertension
b) Primary or secondary open angle glaucoma
c) angle closure glaucoma
d) all of the above are indications for OBB use
d) all of the above are indiactions for OBB use
- Which one of the following is NOT a contraindication regarding the use of OBB’s?
a) pt’s with pulmonary disease (COPD)
b) pt’s with bradycardia (less than 60 bpm resting)
c) pt’s with sulfa allergies
d) pt’s with hypersensitivity to beta-blockers
c) pt’s with sulfa allergies (sulfa allergies is a contraindication with CAI’s–carbonic anhydrase inhibitors)
(T/F) OBB’s are typically given BID (twice daily) but can be given QD (once daily) to minimize side effects
true.
Most OBB”s can be prescribed BID (twice daily), however, there are 3 exceptions that are only prescribed QD (once daily). Which one of the following is NOT one of those exceptions?
a) Istalol-qam
b) timolol-qpm
c) timoptic XE or GFS gel-qd
d) betagan-qd
b) timolol-qpm. (Timolol is usually prescribed BID because it has a maximum effect of 12 hours and the pm dose is weaker at reducing IOP below baseline levels)
- gels are only qd because of improved bioavailability, meaning the drug can stay longer on the eye and more drug can be absorbed
- istalol is only qd because it is formulated with potassium sorbate which enhances bioavailability
Which one of the following is the most commonly used OBB today?
a) propranolol
b) practolol
c) timolol
d) metoprolol
c) timolol (timolol maleate is more common than timolol hemihydrate)
Most OBB’s contain the preservative BAK. Which 3 of the following do NOT contain BAK?
a) Timoptic unit dose–preservative free
b) Timoptic XE–Benzododecinum bromide 0.012%
c) Timolol GFS–Benzododecinum bromide 0.012%
d) Betagan-preservative free
a) Timoptic unit dose–preservative free
b) Timoptic XE–Benzododecinum bromide 0.012%
c) Timolol GFS–Benzododecinum bromide 0.012%
d) Betagan-preservative free (FALSE, betagan is not preservative free, it contains BAK)
- Which one of the following is NOT true regarding OBB’s?
a) Timolol is non-selective
b) Betaxolol is a selective beta blocker that can be used in pt’s with pulmonary disease
c) Gels, such as Timoptic XE have increased systemic absorption because they do not drain as fast as drops
d) Betaxolol is less effective compared to timolol
- c) Gels, such as Timoptic XE have increased systemic absorption because they do not drain as fast as drops (this is FALSE, gels decrease systemic absorption because systemic absorption happens in the nasolacrimal duct and gels do not drain thru the lacrimal ducts as readily as the drops)
- more selective=less effective
Which one of the following is NOT true regarding Timolol?
a) onset of action is 30 minutes following instillation of drops
b) peak action 2 hours
c) maximal effect can persist for 12 hours
d) IOP lowering persists for 24 hours
e) all of the above are true
e) all of the above are true
(T/F) Timolol is usually prescribed BID, however, there is doubt regarding its efficacy on the PM dose since it does not seem to reduce IOP below baseline levels as in AM doses.
true
Which of the following is NOT true regarding “short term escape”?
a) It does not happen in all pt’s
b) it is a decrease in efficacy of timolol over time (several weeks)
c) it is a response of beta receptors to constant antagonists
d) There may be a down regulation of beta receptors in target tissue
d) There may be a down regulation of beta receptors in target tissue (false–there may be an UP REGULATION of beta receptors in target tissue)
Which of the following is NOT true regarding “long term drift”?
a) efficacy decreased over months to years
b) Its recommended to do a washout to restore levels
c) We do not know for sure if the cause is lack of efficacy or poor adherence
d) all of the above are true
d) all of the above are true
(T/F) A washout period is where a glaucoma pts stop their medication for a period of 4 weeks or up to 6 weeks (for dark irises) in an attempt to counteract long term drift.
true. (IOP lowering effects may persist for 2 weeks after discontinuation of meds. For darker irises, you may have to do for a little longer because the medications can stick longer to iris pigments.)
(T/F) The preservatives found in OBB’s, such as BAK, are necessary to break the epithelial barrier for better absorption.
true
Which one of the following is NOT true regarding Istalol?
a) it is timolol maleate 0.5%
b) it is formulated potassium sorbate and has enhanced bioavailability
c) it has lower BAK concentration
d) it is used BID
d) it is used BID (false, it is only used QD because of its enhanced bioavailability)
Between a solution and a suspension, which needs to be shaken well?
a suspension. (particles in a suspension settle down to the bottom) Any suspension prescribed must say “shake well” on the label.
Which one of the following is NOT true regarding Betaxolol?
a) It is a non-selective beta blocker
b) It is only available in a suspension, not a solution
c) It is less effective than timolol
d) Lower CNS effects compared to timolol
a) It is a non-selective beta blocker (false- it is selective therefore it can be used in pt’s with pulmonary disorders)
- Also, Betaxolol may posses calcium channel blocker properties which would give it neuroprotective (protecting ganglion cells) effects–but this is only speculation