This medication is used to treat attention deficit hyperactivity disorder (ADHD), as part of a total treatment plan including psychological, educational, and social measures. Unlike other drugs used to treat ADHD, guanfacine is not a stimulant. The exact way that guanfacine works to treat ADHD is unknown. Guanfacine is thought to affect receptors in the parts of the brain that lead to strengthening working memory, reducing distraction, and improving attention and impulse control. Guanfacine may help lessen ADHD symptoms such as being disruptive, inattentive, hyperactive, impulsive, and arguing with adults or losing one's temper.
Read the Patient Information Leaflet provided by your pharmacist before you start using guanfacine and each time you get a refill. If you have any questions, consult your doctor or pharmacist.
Take this medication by mouth as directed by your doctor, usually once daily in the morning or evening. Do not take this medication with a high-fat meal. Doing so may increase the amount of drug you absorb, leading to increased side effects. Swallow this medication whole. Do not crush, chew, or split tablets. Doing so can release all of the drug at once, increasing the risk of side effects.
Do not switch between different forms of this medication without talking with your doctor, because different forms of this medication may not provide the same amount of guanfacine.
Use this medication exactly as prescribed. Dosage is based on your medical condition, weight, and response to treatment. To reduce the risks of side effects (such as low blood pressure, slow heart rate, drowsiness), your doctor may start you at a low dose and gradually increase your dose. Follow your doctor's instructions carefully. Do not take more or less medication or take it more frequently than prescribed. Your condition will not improve any faster and your risks of side effects will increase. Use this medication regularly to get the most benefit from it. To help you remember, take it at the same time each day.
Do not suddenly stop taking this medication without consulting your doctor. Your condition may become worse when the drug is suddenly stopped. Your dose may need to be gradually decreased.
Tell your doctor if your condition persists or worsens.
Drowsiness, dizziness, dry mouth, constipation, tiredness, nausea, headache, and stomach pain may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.
To lower your risk of dizziness and lightheadedness, get up slowly when rising from a sitting or lying position.
To relieve dry mouth, suck on (sugarless) hard candy or ice chips, chew (sugarless) gum, drink water, or use a saliva substitute.
Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.
Tell your doctor immediately if any of these unlikely but serious side effects occur: severe dizziness, slow heartbeat, fainting, mental/mood changes (such as depression, hallucinations).
A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.
In the US -
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
Before taking guanfacine, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.
Before using this medication, tell your doctor or pharmacist your medical history, especially of: kidney disease, liver disease, fainting, blood pressure problems (both low or high), heart disease (such as slow heart rate).
This drug may make you dizzy or drowsy. Do not drive, use machinery, or do any activity that requires alertness until you are sure you can perform such activities safely. Avoid alcoholic beverages.
To reduce the risk of dizziness and fainting, avoid becoming dehydrated or overheated during exercise, especially in hot weather. If dizziness occurs, sit or lie down.
Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).
Children may be more sensitive to the side effects of this drug, especially hallucinations and mental/mood changes.
Older adults may be more sensitive to the side effects of this drug, especially dizziness (more likely when standing up), drowsiness, slow heartbeat, or depression. Dizziness and drowsiness can increase the risk of falling.
During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.
It is unknown if this medication passes into breast milk. Discuss the risks and benefits with your doctor before breast-feeding.
Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.
Some of the products that may interact with this drug include: valproic acid, drugs affecting liver enzymes that remove guanfacine from your body (such as azole antifungals like ketoconazole, rifamycins like rifampin).
Tell your doctor or pharmacist if you also take drugs that cause drowsiness such as: certain antihistamines (such as diphenhydramine), anti-seizure drugs (such as carbamazepine), medicine for sleep or anxiety (such as alprazolam, diazepam, zolpidem), muscle relaxants, narcotic pain relievers (such as codeine), psychiatric medicines (such as chlorpromazine, risperidone, amitriptyline, trazodone).
Check the labels on all your medicines (such as cough-and-cold products) because they may contain drowsiness-causing ingredients. Ask your pharmacist about using those products safely.
If overdose is suspected, contact a poison control center or emergency room immediately. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: severe drowsiness, severe dizziness, severe tiredness, very slow heartbeat, pinpoint pupils.
Do not share this medication with others.
Because this drug can affect your blood pressure and heart rate, your doctor should check your blood pressure and heart rate regularly while you are taking this medication.
If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up. If you miss more than 2 doses in a row, call your doctor to get a new dosing schedule.
Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.
Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.
Information last revised November 2014. Copyright(c) 2014 First Databank, Inc.
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