Patient leaflet - Guanfacine Crescent 3 mg prolonged-release tablets
1. What Guanfacine Prolonged-release Tablets is and what it is used for
What Guanfacine Prolonged-release Tablets is
Guanfacine Prolonged-release Tablets contains the active substance guanfacine. This medicine belongs to a group of medicines which affects brain activity. This medicine can help improve your attention, concentration and make you less impulsive and hyperactive. What Guanfacine Prolonged-release Tablets is used for
This medicine is used to treat ‘attention deficit hyperactivity disorder’ (ADHD) in children and adolescents 6-17 years old for whom current stimulant medication is not appropriate and/or current medication does not adequately control ADHD symptoms. The medicine is given as part of a treatment programme, which usually includes the following:
- psychological therapy
- educational therapy
- social therapy
About ADHD
People with ADHD find it hard to:
- sit still
- concentrate.
ADHD can cause problems with everyday life. Children and young people with ADHD may have difficulty learning and doing homework. They can find it hard to behave well at home, at school or in other places.
2. What you need to know before you take Guanfacine Prolonged-release Tablets
Do not take Guanfacine Prolonged-release Tablets if:
- you are allergic to guanfacine or any of the other ingredients of this medicine (listed in section 6). Warnings and precautions
Talk to your doctor, pharmacist or nurse before taking this medicine if:
- you have low or high blood pressure, heart problems or have a family history of heart problems
- you have fainted recently
- you have thoughts or feelings of suicide
- you suffer from any other psychiatric conditions Talk to your doctor, pharmacist or nurse if you are taking this medicine and:
- experience aggressive feelings or behaviour, or
- have suicidal thoughts or feelings
Guanfacine prolonged-release Tablets may affect your weight and height if taking for long periods, your doctor will therefore monitor your growth.
Do not stop taking Guanfacine prolonged-release Tablets without talking to your doctor. If you suddenly stop taking Guanfacine prolonged-release Tablets, you may develop withdrawal symptoms of increased heart rate and high blood pressure (see section 4).
If any of the above apply to you (or you are not sure), talk to your doctor, pharmacist or nurse before taking this medicine. This is because this medicine can make these problems worse. Your doctor will routinely monitor you to see how this medicine affects you.
Children (under 6 years old) and adults (18 years and over)
This medicine should not be used in children under 6 years of age and adults 18 years and over because it is not known if it works or is safe.
Checks your doctor will do when you take Guanfacine prolonged-release Tablets
Before you start taking this medicine your doctor will
check to make sure this medicine is safe for you and that it will help you. While you are taking this medicine your doctor will repeat these checks weekly during initial dosing, after dose adjustments, at least every 3 months for the first year and then at least twice a year. These checks may include:
- your blood pressure and heart rate and other checks on your heart if appropriate
- your response to treatment, in particular if it makes you sleepy or drowsy
- your height and weight
You should talk to your doctor if you do not feel better or if you feel worse and very sleepy or drowsy after taking this medicine for around 6 weeks. Your doctor may want to review your treatment
Other medicines and Guanfacine prolonged-release Tablets
Tell your doctor, pharmacist or nurse if you are taking, have recently taken or might take any other medicines. This is because Guanfacine prolonged-release Tablets and some other medicines can affect each other. In particular, tell your doctor, pharmacist or nurse if you are taking any of the following types of medicines:
- medicines that lower your blood pressure (antihypertensives)
- medicines for epilepsy such as valproic acid
- medicines that make you sleepy (sedatives)
medicines for mental health problems
(benzodiazepines, barbiturates and antipsychotics)
- medicines that can affect the way Guanfacine prolonged-release Tablets is eliminated by the liver (please see table below)
| Medicines | Used to treat |
| Aprepitant | Nausea and vertigo. |
| Atazanavir, efavirenz, etravirine, fosamprenavir, indinavir, nevirapine, ritonavir, saquinavir | HIV infection. |
Ciprofloxacin, chloramphenicol, clarithromycin, erythromycin, rifabutin, rifampicin, telithromycin | Bacterial infections. |
Fluconazole, itraconazole, posaconazole, ketoconazole | Fungal infections. |
| Crizotinib, imatinib | Cancer. |
| Diltiazem, verapamil | Cardiovascular conditions |
.
| Boceprevir, telaprevir | Viral hepatitis. |
| Suboxone | Substance dependence. |
| Bosentan | Cardiovascular conditions (e.g. constriction of blood vessels in the lung). |
Carbamazepine, oxcarbazepine, phenobarbital, phenytoin, primidone | Used to control epilepsy. |
| Modafinil | Is a medicine that promotes alertness and is used to treat sleep disorders. |
| St. John’s Wort | Is a herbal preparation that is used to treat depression. |
If any of the above apply to you or you are not sure, talk to your doctor, pharmacist or nurse before taking this medicine. Guanfacine prolonged-release Tablets with food, drinks and alcohol
- Do not take this medicine with fatty foods (e.g. high fat breakfast), as it may affect the way this medicine works.
- Do not take grapefruit juice with this medicine as it can have an effect on the way this medicine works.
- Do not drink alcohol when taking this medicine as it may make you sleepy or drowsy.
Pregnancy and breast-feeding
If you are pregnant or breast-feeding, think you may be pregnant or are planning to have a baby, ask your doctor, pharmacist or nurse for advice before taking this medicine.
- Do not take this medicine if you are pregnant or you are not using contraception. It is not known if Guanfacine prolonged-release Tablets will affect your unborn baby.
Do not breast-feed while taking Guanfacine prolonged-release Tablets unless told to do so by your doctor. Driving and using machines
You may feel dizzy and drowsy when taking this medicine, especially at the start of treatment and this may last for 2 to 3 weeks possibly longer. If this happens, do not drive, cycle, use any tools or machines or participate in activities that could cause injury until you know how this medicine affects you. Fainting has also been reported but is not a common effect. Guanfacine prolonged-release Tablets contains lactose
Lactose is a type of sugar. If you have been told by your doctor that you have an intolerance to some sugars, contact your doctor before taking this medicine.
3. How to take Guanfacine prolonged-release Tablets
Your treatment will start under the supervision of an P3698T
| Process Black |
Amendment Date
| 20/08/26 |
appropriate specialist in childhood and/or adolescent behavioural disorders.
Always take this medicine exactly as your doctor, pharmacist or nurse has told you. Check with your doctor, pharmacist or nurse if you are not sure. As part of your treatment your doctor will closely monitor how Guanfacine prolonged-release Tablets is affecting you during initial dosing and/or dose adjustments. How much to take
- Your doctor will start you on 1mg per day. Your doctor may increase your dose based on your body weight and how Guanfacine prolonged-release Tablets is working for you but not by more than 1mg per week. Depending on how you respond to treatment your doctor may increase your dose more slowly. The recommended maintenance dose is between 0.05 up to 0.12mg per kg of bodyweight per day.
- You may not notice an immediate effect upon starting treatment, some patients may notice an improvement after the first week but it could take longer.
- Your daily dose will be between 1 and 7mg depending on your age and how you respond to Guanfacine prolonged-release Tablets, but not more than 7mg. How to take Guanfacine prolonged-release Tablets
- This medicine should be taken once a day either in the morning or evening.
It can be taken with or without food, but do not take it with fatty foods (e.g. high fat breakfast).
- Swallow the tablet whole with a drink of water or other liquid (but not grapefruit juice).
- Do not break, crush or chew the tablet; this will affect how the tablet works. Tell your doctor if you cannot swallow the tablet whole.
Duration of treatment
If you need to take Guanfacine prolonged-release Tablets for more than a year your doctor will monitor your response to treatment and your doctor may stop the medicine for a short time; this may happen during a school holiday. This will show if you still need to take the medicine. If you take more Guanfacine prolonged-release Tablets than you should
If you take more Guanfacine prolonged-release Tablets than you should, talk to a doctor or go to a hospital straight away. Take the medicine pack with you and tell them how much you have taken.
The following effects may happen: low or high blood pressure, slow heart rate, slow breathing rate, feeling tired or exhausted.
If you forget to take Guanfacine prolonged-release Tablets
If you forget a dose, wait until the next day and take your usual dose.
- If you have missed two or more doses talk to your doctor as you may need to restart Guanfacine prolonged-release Tablets with a lower dose.
- Do not take a double dose to make up for a forgotten dose.
If you stop taking Guanfacine prolonged-release Tablets
Do not stop taking this medicine without first talking to your doctor.
- If you stop taking this medicine your blood pressure and heart rate may increase (see section 4 below).
- To stop the medicine, your doctor will slowly reduce your Guanfacine prolonged-release Tablets dose to minimise any side effects.
If you have any further questions on the use of this medicine, ask your doctor, pharmacist or nurse.
4. Possible side effects
Like all medicines, this medicine can cause side effects, although not everybody gets them. If you are worried, speak to your doctor.
If you feel unwell in any way while you are taking your medicine please tell an adult straight away. Serious side effects
The following serious side effects have been reported: feeling drowsy (sedation), feeling dizzy (hypotension), slow heart beat (bradycardia), feeling faint or loss of consciousness (syncope), a serious withdrawal side effect of high blood pressure after suddenly stopping Guanfacine prolonged-release Tablets; symptoms may include headaches, feeling confused, nervousness, agitation, and tremors (hypertensive encephalopathy). Some of these side effects are more likely to occur at the start of treatment and may disappear as you continue with your treatment, if you experience any of these side effects contact your doctor straight away.
Other side effects
The following side effects have been reported. Very common (may affect more than 1 in 10 people)
- feeling sleepy (somnolence)
- feeling tired (fatigue)
- headache
- tummy pain (abdominal pain).
Common (may affect up to 1 in 10 people)
- low heart rate
- blood pressure decreased
- feeling restless or irritable
- trouble sleeping (insomnia) or broken sleep (middle insomnia) or nightmares
- feeling depressed, worried (anxiety) or having mood swings (affect lability)
- lack of energy (lethargy)
- weight gain
- loss of appetite
- have a dry mouth
- wetting yourself (enuresis)
feeling (nausea) or being sick (vomiting)
- diarrhoea, abdominal discomfort or constipation
- low blood pressure when standing up (orthostatic hypotension)
- rash.
Uncommon (may affect up to 1 in 100 people)
- allergic reaction (hypersensitivity)
- chest pain
- indigestion (dyspepsia)
- trouble breathing (asthma)
- feeling weak (asthenia)
- pale skin colour (pallor)
- fits or convulsions
- need to urinate frequently (pollakiuria)
- feeling agitated
- aggression
- changes in liver blood test results (increased alanine aminotransferase)
- increase in blood pressure
- unusual heart rhythm (sinus arrhythmia and first-degree arterioventricular block)
- fast heart beat (tachycardia)
- reduced heart rate
- feeling dizzy when standing up (postural dizziness)
- itchy skin (pruritus)
- seeing or hearing things that are not there (hallucination). Rare (may affect up to 1 in 1,000 people)
- sleeping more than normal (hypersomnia)
- high blood pressure (hypertension)
- feeling unwell (malaise).
Very rare (may affect up to 1 in 10,000 people)
- a serious withdrawal side effect of high blood pressure after suddenly stopping Guanfacine prolonged-release Tablets; symptoms may include headaches, feeling confused, nervousness, agitation, and tremors (hypertensive encephalopathy).
Not known (frequency cannot be estimated from the available data)
- difficulty to get or keep an erection (erectile dysfunction). Reporting of side effects
If you get any side effects, talk to your doctor, pharmacist or nurse or nurse. This includes any possible side effects not listed in this leaflet. You can also report side effects directly via the national reporting system: Yellow Card Scheme, Website: www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store. By reporting side effects you can help provide more information on the safety of this medicine.
5. How to store Guanfacine prolonged-release Tablets
Keep this medicine out of the sight and reach of children. Do not use this medicine after the expiry date which is stated on the carton and blister pack after EXP. The expiry date refers to the last day of that month. Do not store above 25°C. Store in the original package in order to protect from moisture.
Do not use this medicine if the tablets or blister pack look damaged.
Do not throw away any medicines via wastewater or household waste. Ask your pharmacist how to throw away medicines you no longer use. These measures will help protect the environment.
6. Contents of the pack and other information
What Guanfacine prolonged-release Tablets contains
- Each 1mg tablet contains guanfacine hydrochloride equivalent to 1mg of guanfacine
- Each 2mg tablet contains guanfacine hydrochloride equivalent to 2mg of guanfacine
- Each 3mg tablet contains guanfacine hydrochloride equivalent to 3mg of guanfacine
- Each 4mg tablet contains guanfacine hydrochloride equivalent to 4mg of guanfacine
- The other ingredients are hypromellose, methacrylic acid-ethyl acrylate copolymer, lactose monohydrate, povidone, crospovidone Type A, microcrystalline cellulose, silica colloidal anhydrous, glycerol dibehenate, macrogol, magnesium stearate.
- The 3mg and 4mg tablets also contain indigo carmine aluminium lake (E132) and yellow iron oxide (E172) What Guanfacine prolonged-release Tablets looks like and contents of the pack
Guanfacine prolonged-release Tablets is a prolonged-release tablet which means that the active substance is released from the tablet over a period of time. The tablets come in pack sizes of 7, 28 or 84 blisters and HDPE Bottle Pack of 40cc HDPE Bottle with pack of 28 tablets per bottle and 75cc HDPE Bottle with pack of 100 tablets per bottle but not all pack sizes may be available.
- The 1mg prolonged-release tablets are white to off white colour, Round shaped, biconvex tablet debossed with 'GI' on one side and plain on the other side
- The 2mg prolonged-release tablets are white to off white colour, Oval shaped, biconvex tablet debossed with 'G2' on one side and plain on the other side
- The 3mg prolonged-release tablets are light green to green colour, Round shaped, biconvex tablet debossed with 'G3' on one side and plain on the other side
- The 4mg prolonged-release tablets are light green to green colour, Oval shaped, biconvex tablet debossed with 'G4' on one side and plain on the other side Marketing Authorisation Holder and Manufacturer
Crescent Pharma Ltd., Key House, Sarum Hill, Basingstoke, RG21 8SR, UK.
e-mail: Safety@crescentpharma.com
Tel: 01256 772 730
This leaflet was last revised in 08/2026.
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