Master the board step 3

Master the Boards: USMLE Step 3
A 42-year-old woman with a history of hypertension, diabetes, and depression
presents to the clinic with dry eyes and dry mouth. Her medications include
hydrochlorothiazide, metformin, and amitriptyline. Which of the following is the
next step in management?
a. Discontinue amitriptyline and change to sertraline
b. Order antinuclear antibodies
c. Order SS-Ro and SS-La
d. Prescribe eye drops
e. Refer to ophthalmologist
Answer: A. Discontinue amitriptyline and switch to another antidepressant medication
with little/no anticholinergic effects. Anticholinergic effects are most severe with amitriptyline,
but there are almost none with most SSRIs.
Lithium
Lithium is the first-line medication for bipolar and schizoaffective disorders
and treatment and prophylaxis of mood episodes. Side effects are a major reason
for noncompliance. These include the following:
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Acne and weight gain are the most common problems.
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Dose-related tremors, GI distress, and headaches (decrease the dose)
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Hypothyroidism (5 percent)
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Polyuria secondary to medication-induced diabetes insipidus
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Do not use in first trimester of pregnancy. Lithium causes cardiac defects.
Divalproex
Divalproex is the first-line choice for rapid-cycling bipolar disorder or when
lithium is ineffective, impractical, or contraindicated.
Carbamazepine
Carbamazepine is the second-line therapy for bipolar disorder when lithium
and divalproex are ineffective or contraindicated. It is not commonly used
because of serious agranulocytosis and significant sedation.
Basic Science Correlate
Carbamazepine affects the inactivated state of voltage-gated Na + channels,
making fewer channels available to open. Carbamazepine is a CYP450
inducer, and it increases the clearance of warfarin, phenytoin, theophylline,
and valproic acid.
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