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Guanfacine (By mouth)

Guanfacine (GWAHN-fa-seen)

There may be other brand names for this medicine.

This medicine is not right for everyone. Do not use it if you had an allergic reaction to guanfacine.

Take your medicine as directed. Your dose may need to be changed several times to find what works best for you.
For patients with high blood pressure: Take the dose at bedtime unless your doctor tells you differently. This may help you avoid being drowsy during the day.
For patients with ADHD: Take the extended-release tablet at the same time each day, either in the morning or evening. It should not be taken with high-fat meals.
Swallow the extended-release tablet whole. Do not crush, break, or chew it.
Read and follow the patient instructions that come with this medicine. Talk to your doctor or pharmacist if you have any questions.
Missed dose: Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose. Check with your doctor if you miss your dose of the extended-release tablets for 2 or more days in a row.
Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.

Some foods and medicines can affect how guanfacine works. Tell your doctor if you are using carbamazepine, efavirenz, fluconazole, ketoconazole, or rifampin.
Do not drink alcohol while you are using this medicine.
Tell your doctor if you use anything else that makes you sleepy. Some examples are allergy medicine, narcotic pain medicine, and alcohol.

Tell your doctor if you are pregnant or breastfeeding, or if you have kidney disease, liver disease, heart or blood vessel problems, heart rhythm problems, or have had a recent heart attack or stroke.
This medicine may cause the following problems:
- Low blood pressure
- Slow heartbeat
- Increased blood pressure and heart rate after suddenly stopping this medicine (rebound hypertension)
This medicine can make you dizzy, drowsy, or lightheaded, especially if you are dehydrated. Do not drive or do anything else that could be dangerous until you know how this medicine affects you. Stand or sit up slowly if you feel lightheaded or dizzy.
Do not stop using this medicine suddenly. Your doctor will need to slowly decrease your dose before you stop it completely.
Tell any doctor or dentist who treats you that you are using this medicine. You may need to stop using this medicine several days before you have surgery or medical tests.
Your doctor will do lab tests at regular visits to check on the effects of this medicine. Keep all appointments. Your doctor will also check your blood pressure and heart rate while you are using this medicine.
Keep all medicine out of the reach of children. Never share your medicine with anyone.

Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
Chest pain, trouble breathing
Fast, slow, or uneven heartbeat
Headache, confusion, tremors, nervousness
Lightheadedness, dizziness, or fainting

Last Updated: 12/4/2023