Guanfacine is used on its own or together with other medicines to keep your blood pressure under control. It relaxes your blood vessels and this helps to lower your blood pressure.
This medicine is also used in the management of attention deficit hyperactivity disorder (ADHD), a behavioural disorder which includes short attention span, acting without thinking, and being hyperactive.
Take Guanfacine exactly as directed by your doctor or according to the instructions on the label. Do not take more or less than instructed by your doctor.
This medicine is available as an immediate-release or extended-release type of tablet (may be labelled “ER”). Swallow it whole. Do not divide, chew or crush the tablet. Try to take it at the same time each day.
The immediate-release tablet is best taken in the evening before bedtime.
Guanfacine must be taken regularly for it to be effective. Continue taking this medicine even when you feel better. Do not stop taking it suddenly as this may worsen your condition.
Take the missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and return to your normal dosing schedule.
DO NOT double a dose under any circumstances.
If you often forget to take your medicine, let your doctor and pharmacist know.
Inform your doctor if you have the following conditions:
- heart disease e.g. recent heart attack, slow heartbeat, heart block, low blood pressure
- diseases affecting the blood circulation to the brain e.g. stroke
- liver disease
- kidney disease
Let your doctor know if you are pregnant or breastfeeding.
Keep your appointments with your doctor. Your doctor needs to monitor your condition and check your response to the medication regularly. Your doctor may also need to do routine blood tests while you are being treated with Guanfacine.
What lifestyle changes can I make to improve my blood pressure?
Regular exercise and eating a healthy diet will help lower your blood pressure and improve your overall health. Engage in physical activity (e.g. walking) at least 30 to 60 minutes on most days of the week. If you have not exercised for a long time, start with light exercises such as slow walks. Speak to your doctor about what type of exercise would be suitable for you.
Follow a healthy diet plan by eating more fruits, vegetables, whole grains and low-fat dairy products and reduce your intake of foods high in saturated fat, cholesterol and sodium. Cutting down on deep-fried foods and using less salt when cooking can kick-start your healthy diet.
If you smoke, you should try to quit. Smoking is harmful to your blood pressure, heart and overall health. Speak to your doctor or pharmacist about ways to kick your smoking habit.
Try to keep stress levels under control as stress will cause your blood pressure to go up.
Guanfacine may cause dizziness and to suddenly falling asleep during your daily activities such as eating and watching television. If affected, do not drive or take part in any activity in which you need to be alert.
You may also feel dizzy when getting up from a sitting or lying down position, especially if you are taking this medicine for the very first time. This is common and should improve gradually as you get used to Guanfacine. It will help if you get up slowly from a sitting or lying down position and if you take the very first dose of this medicine at bedtime.
Other side effects include any of the following: headache, nausea, dry mouth, constipation, tiredness, weakness, impotence, headache, difficulty sleeping, irritability, stomach pain, decreased appetite and skin rash.
Some side effects may need immediate medical help. Alert your doctor quickly if you experience slow or irregular heartbeat or fainting or passing out.
Inform your doctor if any of these side effects do not go away or are severe, or if you experience other side effects.
Inform your doctor and pharmacist if you are taking any of these medicines:
- medicines for epilepsy (fits or seizures) e.g. phenobarbital, phenytoin
- medicines for anxiety e.g. diazepam, lorazepam
- medicines for water retention (water pills) e.g. furosemide, hydrochlorothiazide
- ketoconazole (medicine for fungal infections)
- rifampicin (medicine for tuberculosis)
This list does not include all medicines that may interact with Guanfacine.
Always notify your doctor and pharmacist if you are taking any other medicines, including herbal tonics such as traditional Chinese medicines, supplements and medicines that you buy without a prescription.
If you are taking the extended-release type of tablet, avoid taking Guanfacine together with high-fat foods. Ask your doctor about the types of food you should avoid.
Store in a cool, dry place away from the reach of children.
Medicines must not be used past the expiry date.