What are the adverse effects of quetiapine (Seroquel)?

Adverse Effects of Quetiapine (Seroquel)

Quetiapine is associated with multiple significant adverse effects including weight gain, sedation, orthostatic hypotension, and potential cardiovascular risks, with the most common side effects being somnolence (57%), dry mouth (44%), dizziness (18%), and constipation (10%). 1

Common Adverse Effects

Neurological Effects

• Sedation and somnolence (up to 57% of patients) are the most frequently reported side effects 1
• Dizziness (11-18% of patients) 1
• Extrapyramidal symptoms (EPS) can occur but are less common than with traditional antipsychotics 2
• Risk of tardive dyskinesia, though lower than with typical antipsychotics 2
• Akathisia (4% in bipolar depression) 1
• Dysarthria and tremor (2-3%) 1

Metabolic Effects

• Weight gain is one of the most significant problems associated with quetiapine use 2
• Increased appetite (5%) 1
• Metabolic effects with long-term use, including potential for hyperglycemia 2
• Elevations in lipid parameters (triglycerides, total cholesterol, LDL) 3

Cardiovascular Effects

• Orthostatic hypotension (4-7% of patients) 2, 1
• Tachycardia (6% in schizophrenia, 2% in bipolar disorder) 1
• QT prolongation has been reported 2
• Increased risk of major adverse cardiovascular events, particularly in women and elderly patients, even at low doses 3

Gastrointestinal Effects

• Dry mouth (9-44% of patients) - extremely common 1
• Constipation (8-10% of patients) 1
• Dyspepsia (5%) 1
• Vomiting (5-6%) 1
• Abdominal pain (4-7%) 1

Hematological Effects

• Risk of leukopenia, though rare 2
• One case report of precipitous drop in absolute neutrophil count (ANC) and platelets in a child receiving quetiapine 2
• While agranulocytosis is primarily associated with clozapine, it can theoretically occur with any antipsychotic agent including quetiapine 2

Hepatic Effects

• May produce elevations in hepatic transaminase levels 2
• These elevations are often transient and generally resolve with cessation of the drug 2

Ocular Effects

• Blurred vision (4%) 1
• Quetiapine was associated with cataract development in animal studies, though this has not been confirmed in humans 2
• FDA recommends baseline and 6-month follow-up eye examinations when prescribing quetiapine 2

Serious Adverse Effects

Respiratory Effects

• Potential for respiratory depression, particularly in elderly patients with underlying pulmonary conditions 4
• Case reports of acute respiratory failure even with a single dose in vulnerable populations 4

Rare but Serious Effects

• Neuroleptic malignant syndrome 2
• Post-marketing reports include anaphylactic reaction, cardiomyopathy, hyponatremia, myocarditis, pancreatitis, rhabdomyolysis, Stevens-Johnson syndrome, and toxic epidermal necrolysis 1
• Syndrome of inappropriate antidiuretic hormone secretion (SIADH) 1

Special Populations

Elderly Patients

• Higher risk of adverse cardiovascular events, even at low doses 3
• Increased risk of sedation and cognitive impairment 2
• Greater susceptibility to orthostatic hypotension 2
• Dose reduction recommended in older patients 2

Patients with Respiratory Conditions

• Extreme caution in patients with COPD or other respiratory conditions due to risk of respiratory depression 4
• Potential for life-threatening respiratory failure even with standard doses 4

Monitoring Recommendations

• Regular monitoring of weight and metabolic parameters (glucose, lipids) 2
• Baseline and periodic liver function tests 2
• Baseline and 6-month follow-up eye examinations 2
• ECG monitoring in patients with cardiovascular risk factors or if using high doses 2
• Blood pressure monitoring, particularly when initiating therapy or increasing doses 2

Risk Mitigation

• Start with lower doses in elderly patients and those with hepatic impairment 2
• Avoid combination with benzodiazepines due to risk of oversedation and respiratory depression 2
• Use caution when prescribing to patients with cardiovascular disease 3
• Consider alternative medications for off-label uses such as insomnia or anxiety, particularly in elderly patients 3
• Monitor for signs of potential abuse or dependence, particularly in patients with substance use disorders 5