Side Effects of Guanfacine to Be Aware of — Talkspace

Serious Side Effects of Guanfacine

Though Guanfacine can effectively treat ADHD, there are some serious risks to consider. Understanding these potential risks before taking Guanfacine is vital to make an informed treatment decision.

“Sedation, dry mouth, and dizziness can be side effects of Guanfacine. If these persist, please reach out to your doctor.”

– Talkspace psychiatrist Dr. Dion Metzger

Slowed heart rate

One of Guanfacine’s serious adverse effects is slowed heart rate. A slow heart rate can cause dizziness, fatigue, and fainting spells. If any of these occur while taking Guanfacine, contact your doctor immediately.  

Heart block (ER form)

Heart block occurs when electrical signals between the upper and lower chambers of the heart become blocked or delayed. Signs of heart block may include chest distress, breathing difficulty, dizziness, and an uneven heartbeat. If you have any symptoms of heart block, immediately seek medical help.

Very low blood pressure (ER form)

Hypotension, or very low blood pressure, is a serious side effect of Guanfacine. If you feel faint or unsteady when rising quickly from a sitting or reclined position, it may indicate low blood pressure resulting from taking Guanfacine. 

Hallucinations (ER form)

If any hallucination occurs while taking Guanfacine, it is important to speak with your doctor about adjusting the dosage accordingly to prevent further issues from arising over time. 

Wheezing

Wheezing is a rare yet severe side effect of Guanfacine and should be taken seriously. If you experience difficulty breathing or a sensation of tightness around your throat area after taking Guanfacine, seek medical attention immediately.

Severe allergic reactions

If any type of severe allergic reaction occurs while taking Guanfacine, get emergency assistance immediately to avoid potentially life-threatening consequences. Signs and symptoms may include hives/rash on the skin surface area(s), swelling around eyes/mouth areas, itching sensations throughout body parts, difficulty breathing, extreme dizziness, and nausea, among other things.

Fainting or passing out

Experiencing sudden weakness or dizziness followed by an actual loss of consciousness is an uncommon but potential event linked with taking Guanfacine for treating ADHD. If any fainting or passing out occurs while taking Guanfacine, get medical help immediately. 

Seizures (ER form)

Seizures can be a serious side effect of taking Guanfacine for treating ADHD conditions. Warning signs vary from person to person, but common ones include uncontrollable jerking movements and loss of awareness. 

High blood pressure if stopped suddenly

When abruptly stopping Guanfacine, high blood pressure is a common side effect.  

Withdrawal symptoms if stopped suddenly

Discontinuing Guanfacine without consulting medical professionals can result in mild to severe withdrawal symptoms, including headaches, nausea, and vomiting. Talk to a doctor before quitting medication to avoid Guanfacine withdrawal.