Adverse Effects of Duloxetine and Approach to Ataxia

Common Adverse Effects of Duloxetine

• The American College of Cardiology is not directly mentioned, however, duloxetine can cause gastrointestinal and neurological symptoms, including nausea, dry mouth, headache, constipation, dizziness, decreased appetite, somnolence, and fatigue, which are typically mild to moderate and most prominent in the first week of treatment 1, 2
• Duloxetine can increase systolic and diastolic blood pressure and heart rate 1
• Rare serious effects of duloxetine include hepatic failure, severe skin reactions, suicidal thinking, and serotonin syndrome, which are uncommon 1, 2

Clinical Approach When Ataxia Develops

• When a patient on duloxetine presents with ataxia, a systematic evaluation of other causes is necessary, including review of concurrent medications, as duloxetine is a moderate CYP2D6 inhibitor that could increase levels of other medications that cause ataxia 2
• CNS depressants, such as benzodiazepines, antipsychotics, or other sedatives, are well-documented causes of ataxia and dyscoordination 2
• Anticholinergics commonly cause neurological side effects, including coordination problems 2
• A neurological evaluation should be performed to rule out stroke, particularly posterior circulation strokes, and to assess for neurodegenerative disease or structural brain pathology 2
• The American College of Radiology guidelines suggest examining for cerebellar pathology, such as mass lesions, paraneoplastic syndromes, or inflammatory conditions affecting the cerebellum 3
• Substance abuse, including chronic ethanol abuse, methanol toxicity, heroin use, and solvent abuse, can cause cerebellar atrophy and ataxia 3
• Medication toxicity, such as metronidazole or gabapentin, has documented associations with ataxia 3
• Nutritional deficiencies, such as vitamin E deficiency, can cause cerebellar atrophy and ataxia 3
• Infectious causes, such as bacterial cerebellitis or acute disseminated encephalomyelitis, can present with ataxia 3
• Autoimmune disorders, such as vasculitides or demyelinating diseases, may cause ataxia 3
• Paraneoplastic syndromes, such as subacute cerebellar degeneration associated with malignancy, can present with gait and limb ataxia 3

Management of Duloxetine-Related Adverse Effects

Timeline for Adverse Effect Resolution

• Headaches should substantially improve or resolve by week 2-3 of continuous duloxetine therapy, as the transient nature of these side effects means they tend to diminish as the body adjusts to the medication 4

Monitoring and Follow-Up

• Clinicians should assess patient status, therapeutic response, and adverse effects within 1-2 weeks of initiating duloxetine therapy to ensure tolerability and appropriate symptom management, as recommended by the American College of Physicians, as published in the Annals of Internal Medicine 5
• Persistent or worsening headaches beyond the initial adaptation period may indicate the need to modify treatment, as recommended for inadequate therapeutic response, according to the Annals of Internal Medicine 5