Review of Pharmacology - 9E (2015)

Review of Pharmacology
Explanations
Other Topics and Adverse Effects
704
1. Ans. (b) -Vitreomacular adhesion (Ref: http://www.revophth.com/content/d/retinal_insider/c/40601/)
Ocriplasmin is a recombinant protease with activity against fibronectin and laminin, components of the vitreoretinal interface.
It is approved by FDA for treatment of symptomatic vitreomacular adhesion (VMA). It works by dissolving the
proteins that link the vitreous to the macula, resulting in posterior detachment of the vitreous from the retina.
There are two primary indications for ocriplasmin. The first is for patients who have mild to moderate symptomatic
VMA, and also have good visual acuity. Vitrectomy surgery would not be a viable option for this group, because their
vision is too good to risk the complications associated with surgery. The FDA approval of ocriplasmin provided surgeons
with a minimally invasive means of treating these patients who previously had no viable option.
The second set of patients are those with more moderate VMA whose visual acuity has deteriorated to 20/80 or worse,
sufficient to justify surgery. Ocriplasmin is the ideal first choice in these patients.
2. Ans. (a) Phenytoin (Ref: CMDT 2012/1120)
Phenytoin inhibit the hepatic production of 25 hydroxy vitamin D and also directly inhibit bone mineralization and thus
may result in osteomalacia. Steroids and heparin result in osteoporosis not osteomalacia.
Important drugs causing osteomalacia are:
• Phenytoin
• Carbamazepine
• Valproate
• Phenobarbitone
• Bisphosphonates
3. Ans. (d) Clonidine (Ref: KK Sharma 2/e p174)
• Clonidine is α 2
agonist and decreases the central sympathetic outflow. It decreases blood pressure as well as heart rate.
4. Ans. (a) Sodium Nitroprusside (Ref: CMDT 2012/1533)
5. Ans. (a) Erectile dysfunction (Ref: Internet)
• Bremelanotide functions by activating the melanocortin receptors.
• It was shown to be effective in treating sexual dysfunction in both men (erectile dysfunction or impotence) and
women (sexual arousal disorder).
6. Ans. (d) Voclosporin (Ref: Internet)
Friends, it is very unfortunate that AIIMS people are asking such type of questions. How can a medical student be expected
to know about the trials about a drug which we are sure even many ophthalmology resident are not aware of. So we will
suggest just to remember the answer and do not go for details.
The LUMINATE (Lux Uveitis Multicenter Investigation of a New Approach to TrEatment) clinical development program
was initiated in 2007 to assess the safety and efficacy of voclosporin for the treatment, maintenance, and control of all
forms of noninfectious uveitis.
7. Ans (a) Insulin glucose IV (Ref: CMDT 2010/799)
Severe hyperkalemia requires emergent treatment directed at minimizing membrane depolarization, shifting K + into
cells, and promoting K + loss.
• Administration of calcium gluconate decreases membrane excitability. The effect begins within minutes but is short-lived
(30–60 min), and the dose can be repeated if no change in the electrocardiogram is seen after 5–10 min.
• Insulin causes K + to shift into cells and will temporarily lower the plasma K + concentration. Although glucose
alone will stimulate insulin release from normal pancreatic beta cells, a more rapid response generally occurs when
exogenous insulin is administered (with glucose to prevent hypoglycemia). The plasma K + concentration will fall by
0.5–1.5 mmol/L in 15–30 min, and the effect will last for several hours.
• Alkali therapy with intravenous NaHCO 3
can also shift K + into cells. This should be reserved for severe hyperkalemia
associated with metabolic acidosis. Patients with end-stage renal disease seldom respond to this intervention and
may not tolerate the Na + load and resultant volume expansion.
• When administered parenterally or in nebulized form, beta 2-adrenergic agonists promote cellular uptake of K + . The
onset of action is 30 min and the effect lasts 2–4 h.
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