A 63-year-old woman comes to the office for a hypertension follow-up. Her blood pressure was high at her 2 previous visits despite changes in diet and exercise routine. The patient has a history of bipolar disorder with 3 hospitalizations for treatment of manic and depressive episodes. She has not been hospitalized during the past 6 years, and her symptoms have been well controlled on lithium. The patient has no other medical conditions and takes no other medications. Blood pressure is 148/90 mm Hg and pulse is 78/min. Findings from neurologic and cardiovascular examinations are within normal limits. On mental status examination, the patient is calm and speech is nonpressured. Affect is euthymic; there is no suicidal ideation. A recent serum chemistry panel, including electrolytes and renal function markers, is normal. ECG is also normal. The physician decides to prescribe an antihypertensive medication but wants to continue the patient's lithium, which is working well. Which of the following medications will be most appropriate?

Question

A 63-year-old woman comes to the office for a hypertension follow-up.  Her blood pressure was high at her 2 previous visits despite changes in diet and exercise routine.  The patient has a history of bipolar disorder with 3 hospitalizations for treatment of manic and depressive episodes.  She has not been hospitalized during the past 6 years, and her symptoms have been well controlled on lithium.  The patient has no other medical conditions and takes no other medications.  Blood pressure is 148/90 mm Hg and pulse is 78/min.  Findings from neurologic and cardiovascular examinations are within normal limits.  On mental status examination, the patient is calm and speech is nonpressured.  Affect is euthymic; there is no suicidal ideation.  A recent serum chemistry panel, including electrolytes and renal function markers, is normal.  ECG is also normal.  The physician decides to prescribe an antihypertensive medication but wants to continue the patient's lithium, which is working well.  Which of the following medications will be most appropriate?

Quizplus · Accepted Answer

Explanation: 11ec2b69_c05e_03ed_8f63_53bd19ded018_MD0005_00 Lithium is a mineral salt used in the treatment of bipolar disorder. It is eliminated exclusively by the kidneys; lithium is readily filtered in the glomerulus but can be reabsorbed by transport proteins in the proximal tubule that normally handle sodium and potassium. Lithium has a narrow therapeutic index (ie, the difference between the minimum effective dose and the toxic dose is relatively small) and drugs that affect glomerular filtration or renal reabsorption can dramatically alter serum levels, leading to toxicity or loss of therapeutic effect: Nonsteroidal anti-inflammatory drugs (eg, ibuprofen), ACE inhibitors (eg, lisinopril), and angiotensin II receptor blockers (eg, losartan) can acutely reduce glomerular filtration and therefore clearance of lithium, potentially leading to drug toxicity (Choices C and D). Thiazide diuretics (eg, hydrochlorothiazide) inhibit reabsorption of sodium in the distal convoluted tubule, causing a compensatory increase in reabsorption of sodium-and concurrently lithium-in the proximal tubule (Choice B). Some potassium-sparing diuretics (eg, spironolactone) also can raise lithium levels, whereas others (eg, amiloride) can lower lithium levels, likely due to effects on both sodium transport and glomerular filtration (Choice E). Calcium channel blockers (eg, amlodipine) are usually considered safe because they do not significantly affect sodium level or glomerular filtration rate. Educational objective: Many antihypertensive medications can interact with lithium due to their effects on renal function and electrolyte reabsorption. Thiazides, ACE inhibitors, and angiotensin II receptor blockers can increase serum lithium levels. Calcium channel blockers are generally considered safe.

A 63-Year-Old Woman Comes to the Office for a Hypertension