Guanfacine Adverse Effects

Incidence and Mechanism of Adverse Effects

• Guanfacine is a centrally acting alpha-2-adrenoreceptor agonist, and dry mouth is a common effect of drugs in this class 2, 3
• The documented higher specificity of guanfacine to alpha-2A receptors may contribute to differences in adverse effect profiles compared to other similar medications 3

Comparison with Other Similar Medications

• Adverse effects of clonidine and guanfacine are generally considered very similar due to their shared mechanism of action 1, 2
• For clonidine specifically, dry mouth is explicitly mentioned as a common adverse effect, along with sedation, bradycardia, and syncope 1, 2
• While both medications can cause dry mouth, guanfacine may have a lower incidence of sedative effects compared to clonidine due to its higher specificity for alpha-2A receptors 3

Other Common Adverse Effects of Guanfacine

• Besides dry mouth, common adverse effects include somnolence/sedation 1, 4
• Headache is also a common adverse effect of guanfacine 4
• Irritability is a common adverse effect of guanfacine 1
• Hypotension/bradycardia are common adverse effects of guanfacine 4

Important Considerations When Prescribing

• Guanfacine should not be abruptly discontinued after prolonged use, as rebound hypertension can occur; the medication should be tapered off 4
• Monitoring for cardiovascular effects (heart rate, blood pressure) is recommended, particularly when initiating therapy 4
• The extended-release formulation of guanfacine is FDA-approved for ADHD treatment, while immediate-release formulations are typically used for hypertension 1, 2