Dear Editor:
Much has been written about the use and side effects profile of duloxetine (Cymbalta®). We report a case of a patient who had generalized tonic clonic seizures after abruptly stopping duloxetine.
Case report. Ms. X was a 59-year-old Caucasian woman with a diagnosis of major depressive disorder recurrent severe without psychotic feature. She was stabilized on duloxetine 90mg p.o. daily. She came to the emergency room with complaints of nausea, clear liquid vomitus, anxiety, “electical sensation” inside the body, restlessness, decreased liquid intake, abdominal pain, and decreased sleep. She stopped taking her duloxetine two days previoiusly. She had two generalized tonic clonic seizures 20 minutes apart in the hospital. Urine drug screen was negative. Urinalysis was negative. Complete blood count (CBC) was normal. Her sodium was 134, potassium was 2.5, chloride 86, glucose 110, calcium 9, and magnesium 1.5. Her blood urea nitrogen (BUN) and creatinine were normal. Her liver function tests were normal except mildly elevated alkaline phosphatase of 126. Computed tomography (CT) scan of her head was negative. There was no sign of infection at the point of admission. She was stabilized and was then started on a different antidepressant due to her history of nonadherence. She had no further seizures during her hospital stay.
Discussion. Major depression affects 5 to 13 percent of medical outpatients,1 yet is often undiagnosed and untreated.2,3 Moreover, it is often undertreated when correctly diagnosed.3
Serotonin-norepinephrine reuptake inhibitors, such as venlafaxine and duloxetine, block monoamine transporters more selectively than tricyclic antidepressants and they have good cardiac profiles as compared to tricyclics antidepressant.4 Venlafaxine and duloxetine are effective for the treatment of chronic pain5 and diabetic neuropathic pain,6 respectively, as well as pain occurring as part of primary or secondary depression.7,8 Duloxetine is also used for stress incontinence.9 There are some data suggesting the better efficacy of serotonin-norepinephrine reuptake blockers over serotonin reuptake blockers.10 Duloxetine would not be expected to cause clinically significant inhibition of the metabolic clearance of drugs metabolized by P450 (CYP)3A, (CYP)1A2, (CYP)2C9, or (CYP)2C19, but would be expected to cause some inhibition of CYP 2D6. Duloxetine should not be used in combination with CYP 1A2 inhibitors or nonselective, irreversible monoamine oxidase inhibitors.11 Precaution should be taken with patients having hepatic function abnormality and elevated blood pressure.
We believe that this is the first reported case in which a person developed duloxetine withdrawal seizure secondary to deranged electrolytes after abruptly stopping duloxetine. We should be particularly careful in patients taking duloxetine with histories of nonadherence and seizure disorder.
With regards,
Abdul Qadir, MD
Third Year Psychiatry Resident University of North Dakota Neuroscience Department Fargo, North Dakota E-mail: abdul.qadir@meritcare.com aqadir@medicine.nodak.edu
Naveed Haider, MD
Staff Psychiatrist Merit Care Psychiatric Services PO Box MC Fargo, ND 58122-0390 E-mail: Naveed.Haider@meritcare.com
Contributor Information
Abdul Qadir, Third Year Psychiatry Resident University of North Dakota Neuroscience Department Fargo, North Dakota E-mail: abdul.qadir@meritcare.comaqadir@medicine.nodak.edu.
Naveed Haider, Staff Psychiatrist Merit Care Psychiatric Services PO Box MC Fargo, ND 58122-0390 E-mail: Naveed.Haider@meritcare.com.
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