What Are the Most Common Guanfacine Side Effects?

The most common of the potential guanfacine side effects are drowsiness and dizziness. The use of guanfacine can result in side effects ranging from mild to moderate, such as drowsiness or dry mouth, as well as more serious or potentially life-threatening reactions. Guanfacine is a medication prescribed under the brand names Intuniv® and Tenex®.

Most commonly, mild to moderate guanfacine side effects often include drowsiness or dizziness. Some users experience fatigue, dry mouth, headache, loss of appetite, constipation, or mood changes. Nausea, stomach pain, insomnia, or leg cramps are also possible with this medication.

Serious guanfacine side effects could include low blood pressure, fainting, lowered heart rate, shortness of breath, skin rash, swelling of extremities, or blurred vision. Users of guanfacine should consult their doctors immediately if any of these side effects occur. Individuals are urged to avoid overheating or dehydration while taking this medication, due to the danger of fainting as a potential guanfacine side effect.

The experience of any existing guanfacine side effects could be intensified if combined with alcohol. Using guanfacine can also increase the potential sleepiness or dizziness reaction of other medications. For this reason, it is considered dangerous to combine this medication with certain other types of prescriptions and supplements, including St. John's Wort or other antidepressants, antihistamines, barbiturates, and sedatives.

Guanfacine is contraindicated for individuals who have previously experienced a stroke or heart attack, anyone with bipolar disorder, and those with diseases of the heart, liver, or kidneys. Patients are urged to have regular checks of their heart rate and blood pressure while using this medication. This drug should not be stopped abruptly, due to the risk of anxiety attacks or increased blood pressure.

This drug could have serious effects in the case of overdose. Symptoms of guanfacine overdose could include lethargy, unconsciousness, blurred vision, or contracted pupils. In the event of an overdose of this medication, individuals should request emergency assistance.

Potential guanfacine side effects for pregnant or nursing women are unknown. Women who are pregnant or might become pregnant while taking this drug should speak with their doctors about the risks. This medication is believed to be excreted in breast milk.

Guanfacine is prescribed in a long-acting timed release formulation under the brand name Intuniv® as treatment for attention deficit hyperactivity disorder (ADHD). Typically, this prescription medication is used in conjunction with other ADHD treatment approaches, such as counseling. In a non-extended release tablet form, guanfacine is also prescribed for hypertension under the brand name Tenex®. In general, this medication is taken once per day. Guanfacine sometimes requires several days to take effect.