guanfacine
Guanfacine is used to treat high blood pressure, but it's not a first-choice option. It's taken by mouth, typically once a day at nighttime. Common side effects of guanfacine include sleepiness, dizziness, and dry mouth. Some medications, such as sleep medications or certain pain medications, can interact with guanfacine by worsening those side effects. The brand name Tenex is no longer available.
What is Guanfacine?
What is Guanfacine used for?
High blood pressure in people ages 12 years and older
How Guanfacine works
Guanfacine is an alpha-2 agonist. It works by binding (attaching) to alpha-2 receptors in the brain. This lowers the amount of norepinephrine, a chemical that normally raises your blood pressure by squeezing your blood vessels.
Drug Facts
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What are the side effects of Guanfacine?
Common Side Effects
- Dry mouth (up to 54%)
- Sleepiness (up to 39%)
- Dizziness (up to 15%)
- Constipation (up to 15%)
- Headache (up to 13%)
- Weakness (up to 10%)
- Tiredness (up to 10%)
Other Side Effects
- Confusion
- Leg cramps
- Upset stomach
- Erectile dysfunction
- Rash
Serious Side Effects
- Severely low blood pressure: lightheadedness, dizziness, feeling faint, tiredness, confusion
Source: DailyMed
More on Guanfacine side effects
The following side effects have also been reported
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
More common
Blurred vision
confusion
dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
sweating
unusual tiredness or weakness
Less common
Chest pain or discomfort
difficulty with breathing
fast, slow, pounding, or irregular heartbeat
increased need to urinate
lightheadedness, dizziness, or fainting
mental depression
noisy breathing
passing urine more often
tightness in the chest
Incidence not known
Agitation
back pain
cracks in the skin
drowsiness
fast, pounding, or irregular pulse
feeling of constant movement of self or surroundings
headache
irritability
loss of consciousness
loss of heat from the body
mood or mental changes
numbness or tingling in the arms, legs, or face
red, swollen skin
seeing or hearing things that are not there
seizures
sensation of spinning
stiff neck
swelling
vomiting
weakness
Get emergency help immediately if any of the following symptoms of overdose occur:
Symptoms of overdose
Dizziness (extreme) or faintness
unusual tiredness or weakness (severe)
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
More common
dizziness
dryness of the mouth
sleepiness or unusual drowsiness
unusual dullness or feeling of sluggishness
upper abdominal or stomach pain
Less common
Belching
decreased appetite
decreased sexual ability
dry, itching, or burning eyes
indigestion
lack or loss of strength
paleness of the skin
stomach discomfort, upset, or pain
trouble with sleeping
Incidence not known
Change in taste
decreased interest in sexual intercourse
difficulty in moving
general feeling of discomfort or illness
hair loss, thinning of hair
inability to have or keep an erection
joint pain or swelling
leg cramp or pain
loss in sexual ability, desire, drive, or performance
muscle ache, cramp, pain, or stiffness
seeing or hearing things that are not there
After you stop using this medicine, it may still produce some side effects that need attention. During this period of time, check with your doctor immediately if you notice the following side effects:
Anxiety or tenseness
increased salivation
nervousness or restlessness
shaking or trembling of the hands and fingers
stomach cramps
sweating
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Pros and cons of Guanfacine
Pros
Available in a lower-cost generic version
Taken once a day
Taken by mouth
Cons
Not a first-choice option for treating high blood pressure
Stopping suddenly can lead to anxiety and nervousness
Can cause sleepiness and dizziness
Pharmacist tips for Guanfacine
You might feel dizzy when you start taking guanfacine, and when the dose is raised. This should get better over time as you continue taking the medication and your body gets used to your new blood pressure. Take guanfacine at bedtime to help lower the amount of side effects (e.g., sleepiness, dizziness, etc.) you feel during the day.
Dry mouth is a common side effect of guanfacine. There are several things you can do to help treat this, such as chew sugar-free gum, sip liquids or chew ice chips throughout the day, and use saliva substitutes (e.g., BioXtra). Talk to your provider if dry mouth is a bothersome issue that's not getting better with self-care treatments.
Take guanfacine exactly as prescribed. Don't change your dose or suddenly stop taking the medication without talking to your provider first. Doing so can cause your blood pressure to rise quickly. If you want to stop guanfacine, ask your provider if it's safe to do so. You might need to lower your dose slowly over time before you can completely stop taking it.
Your provider might have you measure and record your blood pressure at home and bring a record to your medical appointments. This will help your provider see how well the medication is working for you and if any adjustments to your dose or treatment plan are needed.
Make sure to have a healthy diet, including a low-salt diet, while taking guanfacine to help lower your blood pressure. Depending on your risk factors and other medical problems, it's possible you might be able to stop taking guanfacine if your blood pressure gets within goal.
Frequently asked questions about Guanfacine
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What are the risks and warnings for Guanfacine?
Guanfacine can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Extreme sleepiness and dizziness
Risk factors: Taking high doses of guanfacine | Age 65 years or older | Drinking alcohol | Taking other medications that can cause sleepiness
Guanfacine can cause extreme sleepiness and drowsiness, especially if you're taking higher doses. This can affect your ability to think, react, and focus. Your risk is higher if you're also taking other medications that can cause drowsiness, such as benzodiazepines, anxiety medications, muscle relaxants, and sleep medications. Make sure you know how this medication affects you before driving a car or doing activities that require your concentration. Talk to your healthcare provider right away if you feel too sleepy from guanfacine.
Nervousness and anxiety (from stopping guanfacine too suddenly)
Don't suddenly stop taking guanfacine without first talking with your provider. Doing so can lead to side effects, such as nervousness and anxiety. More rarely, it can lead to high blood pressure. If you want to stop guanfacine, your provider can help you do so safely by lowering your dose slowly over time.
Guanfacine dosage forms
Typical dosing for Guanfacine
The typical recommended dose is 1 mg by mouth once a day at bedtime. If needed, your provider might raise your dose after 3 to 4 weeks. The maximum recommended dose is 2 mg once a day.
More on Guanfacine dosage forms
Interactions between Guanfacine and other drugs
More on Guanfacine interactions
Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
- Abametapir
- Conivaptan
- Fosnetupitant
- Iobenguane I 131
- Netupitant
Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
- Yohimbine
How much does Guanfacine cost?
What are alternatives to Guanfacine?
High blood pressure in people ages 12 years and older
What is the latest news about Guanfacine?
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References
Best studies we foundChartwell RX, LLC. (2023). Guanfacine hydrochloride- guanfacine tablet [package insert]. DailyMed.
Under, T., et al. (2020). 2020 International Society of Hypertension global hypertension practice guidelines. Hypertension.
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