What are the side effects of Seroquel (quetiapine)?

Side Effects of Quetiapine (Seroquel)

Quetiapine (Seroquel) has numerous significant side effects including sedation, weight gain, metabolic disturbances, orthostatic hypotension, and extrapyramidal symptoms, with sedation and dry mouth being the most common adverse effects. 1

Common Side Effects

Quetiapine causes a range of common side effects that patients should be aware of:

• Sedation/somnolence: Occurs in up to 57% of patients, making it one of the most frequent side effects 1
• Dry mouth: Reported in up to 44% of patients 1
• Dizziness: Occurs in approximately 18% of patients 1
• Constipation: Affects about 10% of patients 1
• Lethargy/fatigue: Reported in 5-10% of patients 1
• Headache: Common across various patient populations 1
• Increased appetite: Can contribute to weight gain 1
• Nasal congestion: Occurs in approximately 5% of patients 1

Metabolic and Cardiovascular Effects

Quetiapine has significant metabolic effects that require monitoring:

• Weight gain: Common and clinically significant, requiring regular monitoring 1
• Hyperglycemia/diabetes risk: Can lead to ketoacidosis, coma, or death in severe cases 1
• Increased cholesterol and triglycerides: May occur without symptoms 1
• Orthostatic hypotension: Can cause lightheadedness or fainting, particularly when standing up quickly 1
• Increased heart rate: Average increase of 7 beats per minute compared to placebo 1
• QTc interval prolongation: May affect cardiac conduction 2

Neurological Side Effects

Quetiapine can cause various neurological adverse effects:

• Extrapyramidal symptoms (EPS): Though less common than with typical antipsychotics, can include:
  • Tardive dyskinesia: Involuntary movements that may not resolve after stopping medication 1
  • Akathisia: Restlessness and inability to remain still 1
  • Tremor: Reported in approximately 2% of patients 1
• Dizziness: Common and may contribute to fall risk 1
• Dysarthria: Difficulty with speech articulation 1
• Balance disorders: Can increase fall risk, especially in elderly patients 1, 2

Rare but Serious Side Effects

Several rare but potentially life-threatening side effects require immediate medical attention:

• Neuroleptic malignant syndrome: Characterized by high fever, muscle rigidity, altered mental status 1
• Serotonin syndrome: When combined with other serotonergic medications 2
• Severe allergic reactions: Including anaphylaxis 1
• Seizures: Particularly in patients with seizure disorders 1
• Low white blood cell count: May increase infection risk 1
• Cataracts: Requires regular eye examinations 1
• Abnormal thyroid function: May require thyroid monitoring 1
• Priapism: Prolonged, painful erection requiring emergency treatment 1
• Pancreatitis: Rare but serious inflammatory condition 1

Special Population Considerations

Certain populations may be at higher risk for specific side effects:

Elderly Patients

• More susceptible to orthostatic hypotension and falls
• Higher risk of sedation and cognitive impairment 2
• Should generally avoid quetiapine due to anticholinergic effects and risk of delirium 2

Children and Adolescents

• Increased risk of suicidal thoughts and behaviors
• More pronounced increases in heart rate 1
• Greater susceptibility to weight gain and metabolic effects 1

Monitoring Recommendations

To minimize risks associated with quetiapine:

1. Regular weight monitoring: Check weight at baseline and regularly during treatment
2. Blood glucose testing: Monitor for development of diabetes
3. Lipid panel: Check cholesterol and triglycerides periodically
4. Blood pressure monitoring: Particularly when initiating therapy or changing doses
5. Neurological examination: Assess for development of EPS or tardive dyskinesia
6. Cardiac monitoring: Consider ECG in patients with cardiovascular risk factors

Risk Mitigation Strategies

To reduce the impact of side effects:

• Start with low doses and titrate slowly
• Consider evening dosing to minimize daytime sedation
• Ensure adequate hydration to reduce constipation risk
• Implement dietary counseling to mitigate weight gain
• Monitor for drug interactions, particularly with other CNS depressants

Conclusion

While quetiapine is effective for several psychiatric conditions, its side effect profile requires careful consideration and monitoring. The most common side effects are sedation, dry mouth, and dizziness, while the most concerning are metabolic disturbances, cardiovascular effects, and rare but serious adverse reactions. Regular monitoring and appropriate management of side effects are essential for safe and effective treatment.