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vasospasm which leads to angina or a myocardial infarction.
Histamine has also been shown to induce platelet and tissue
factor into a hypercoagulable state which also contributes to
coronary thrombotic events.
In closing, the author warns that "Cases of Kounis syndrome are more often encountered in clinical practice than
expected." The coincidental occurrence of chest pain and
allergic reaction accompanied by clinical and laboratory
findings of angina should alert the clinician to potential
Kounis syndrome.

Rhabdomyolysis Caused by Risperidone
A 57-year-old male with a longtime history of schizophrenia
was admitted to the hospital for behavioral changes and agitation because he had missed his medication for the past 2 days.
The patient's current medications included aripiprazole 30
mg daily, asenapine 20 mg daily, clonazepam 2 mg daily, and
risperidone 2 mg daily which was initiated 2 weeks before the
patient's hospital admission. In prior years, the patient had
received haloperidol, olanzapine, intramuscular fluphenazine, and intramuscular flupentixol. These medications had
all been utilized in the past and had been discontinued due to
lack of efficacy in managing the patient's schizophrenia. The
patient had tolerated each of these prior antipsychotics without issue except for Ogilvie syndrome which the patient experienced with the use of olanzapine. Ogilvie syndrome is a
rare, acquired disorder characterized by abnormalities affecting peristalsis within the colon. In Ogilvie syndrome, the
colon is often significantly dilated and the patient experiences
symptoms similar to other forms of intestinal pseudo-obstruction and can include nausea, vomiting, abdominal bloating or
swelling, and constipation.
On admission, the patient's vital signs were stable, and his
initial labs including chem-7 and complete blood count were
all within normal limits. The patient's current medications
were restarted, and he received risperidone 25 mg as an intramuscular depot injection. On the patient's third hospital day,
his oral risperidone was increased to 2 mg twice daily. On
hospital day 5, the patient was initiated on trihexyphenidyl 2
mg daily because he began to experience extrapyramidal
adverse effects from his antipsychotic regimen. The patient
then became lethargic and weak and refused to ambulate but
he remained afebrile. The patient then experienced tachycardia of 112 bpm with a stable blood pressure of 124/90 mm
Hg. On examination, the patient reported mild muscle tenderness, but no muscle rigidity, diminished power, or skin
changes. While the patient's laboratory values were normal
on admission, his labs on hospital day 5 revealed a sudden
worsening of renal function with blood urea nitrogen of
73.65 mg/dL (normal range, 8-23 mg/dL) and serum creatinine of 2.9 mg/dL (normal range, male: 0.9-1.3 mg/dL).
Additional abnormal labs included potassium of 5.01 mmol/L
(normal range, 3.5-5 mmol/L), alanine transaminase of 43
U/L (normal range, 10-40 U/L), and aspartate transaminase

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of 151 U/L (normal range 10-30 U/L). His serum creatine
kinase was elevated at 13 735 U/L (normal range, male: ≤195
U/L) and peaked at 73 780 U/L the next day. The patient's
urine myoglobin was evaluated but was found to be within
normal limits.
The patient was diagnosed with acute kidney injury secondary to rhabdomyolysis due to risperidone. The patient
was hydrated and all antipsychotic medications were stopped
immediately. The patient required intermittent hemodialysis
for his renal dysfunction and metabolic abnormalities. The
patient's renal function improved and returned to normal
function. The patient experienced rhabdomyolysis due to an
antipsychotic medication; however, usually this is seen as
part of neuroleptic malignant syndrome which the patient did
not experience. The patient did not experience an elevated
temperature or change in mental status.
In evaluating the patient's rhabdomyolysis, the authors
note the patient did not have any other possible causes for his
rhabdomyolysis besides the initiation of risperidone. "The
fact that he was on two antipsychotics before administration
of risperidone, including aripiprazole, which has a long halflife, may have increased the risk for an adverse effect." The
authors recommend,
We would like to highlight the importance of being vigilant to
the possible development of rhabdomyolysis in patients who are
just started on risperidone or has a recent dose increase. This is
particularly important because it can lead to severe acute kidney
injury with possible life-threatening complications.2

High Incidence of Hyponatremia
With High-Dose TrimethoprimSulfamethoxazole
Tsapepas et al3 conducted a retrospective cohort study of
hospitalized adult patients who received high-dose trimethoprim-sulfamethoxazole (TMP-SMX) over a 2-year
period. Patients included in the study had to receive >8mg/
kg/day of trimethoprim for 3 or more consecutive days.
Patients who had preexisting hyponatremia at the start of
TMP-SMX therapy were excluded as were patients who had
decreased renal function or received therapy which could
cause hyponatremia. The researchers defined hyponatremia
as a serum sodium of less than 136 mEq/L for at least to consecutive calendar days. They categorized patients into 3
groups: normonatremic (Na ≥136 mEq/L), mild hyponatremia (Na 130-135 mEq/L), and moderate-to-severe hyponatremia (Na < 130 mEq/L).
The authors identified 82 instances of high-dose TMPSMX use in 76 unique patients. They found that 72.3% of
patients treated with high-dose TMP-SMX had hyponatremia. Of the 72.3% of patients with hyponatremia, 32.4% had
a nadir sodium level of <130 mEq/L and 40.8% had a nadir
sodium level of 130 to 135 mEq/L. Lower sodium levels were
associated with a longer duration of therapy and a higher

Table of Contents for the Digital Edition of Hospital Pharmacy - July/August 2017