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Clonidine oral high strength


High strength formulation of clonidine hydrochloride.

Drugs List

  • CATAPRES 100microgram tablets
  • clonidine 100microgram tablets
  • Therapeutic Indications





    Initial dose: 50micrograms to 100micrograms 3 times daily.

    Gradually increase dose every second or third day until control is achieved. Normal maintenance dose is between 300micrograms and 1200micrograms per day in divided doses.

    Some patients may require doses over 1800micrograms daily.


    Child 2 to 18 years (unlicensed)
    Initial dose: 0.5micrograms/kg to 1microgram/kg 3 times daily. Dose may be increased gradually if necessary up to a maximum dose 25micrograms/kg daily in divided doses.
    Maximum dose should not exceed 1.2 mg daily.

    Patients with Renal Impairment

    Dosage must be adjusted to the individual antihypertensive response, which can show high variability in patients with renal impairment. Careful monitoring is required.

    Clonidine and its metabolites are extensively excreted in the urine.
    Supplemental dosage of clonidine is not required following dialysis as only a minimal amount of clonidine is removed.

    The Renal Drug Handbook recommends the following doses in renal impairment:

    Glomerular Filtration Rate (ml/minute)
    20ml/minute to 50ml/minute - Dose as in normal renal function.
    10ml/minute to 20ml/minute - Dose as in normal renal function.
    Less than 10ml/minute - Dose as in normal renal function.

    Additional Dosage Information

    Clonidine may be used concurrently with an existing antihypertensive regime if blood pressure has not been controlled with the current medication.

    Existing therapy should be gradually reduced during the introduction of clonidine therapy if the patient is changing treatment.


    Children under 2 years
    Severe bradycardia due to AV block (2nd/3rd degree)
    Severe bradycardia due to sinus node dysfunction

    Precautions and Warnings

    Children aged 2 to 18 years
    Wearing of contact lenses
    Cardiac failure
    Cardiac impairment
    Cerebrovascular insufficiency
    Glucose-galactose malabsorption syndrome
    History of depression
    Ischaemic heart disease
    Lactose intolerance
    Occlusive peripheral vascular disorder
    Renal impairment

    Not suitable for hypertension secondary to phaeochromocytoma
    Advise ability to drive/operate machinery may be affected by side effects
    Contains lactose
    Stop betablocker several days before clonidine if withdrawing combination
    Monitor patients with cardiac failure
    Do not withdraw this drug suddenly
    Advise patient not to take NSAIDs unless advised by clinician
    Advise patient to moderate alcohol intake during treatment
    Advise contact lens wearers of possibility of reduced lacrimation
    Advise patient on possible rebound phenomena on withdrawal

    Patients undergoing anaesthesia should continue their clonidine treatment before, during and after anaesthesia using oral or i.v. administration according to individual circumstances.

    Pregnancy and Lactation


    If clonidine is used during pregnancy it is recommended that the mother and child are monitored. Clonidine passes the placental barrier and may lower the heart rate of the foetus. Post partum a transient rise in blood pressure in the newborn cannot be excluded. There are no data on the long-term effects of pre-natal exposure. Schaeffer (2007) considered clonidine to be a second line choice for treatment of hypertension during pregnancy. Its use is not an indication for termination of the pregnancy or for invasive diagnostic procedures.

    The use of all medication in pregnancy should be avoided whenever possible; particularly in the first trimester. Non-drug treatments should also be considered. When essential, a medication with the best safety record over time should be chosen, employing the lowest effective dose for the shortest possible time. Polypharmacy should be avoided. Teratogens taken in the pre-embryonic period, often quoted as lasting until 14-17 days post-conception, are believed to have an all-or-nothing effect. Where drugs have a short half-life, and when the date of conception is certain, this may allow women to be reassured where drug exposure has occurred within this time frame. Further advice may be available from the UK National Teratology Information Service (NTIS) and through ToxBase, available via password on the internet ( ) or if this is unavailable at the backup site ( ).


    Contraindicated in breastfeeding due to inadequate evidence of safety. Clonidine is secreted into the breast milk. Schaeffer (2007) states that clonidine at the usual maternal doses used for hypertension reaches near therapeutic levels in the breastfed infant, although no adverse effects have been reported. It is recommended that clonidine is not used during breastfeeding, but if already started, weaning is not necessary but the maternal therapy should be changed to a preferred drug for the indication.

    Clonidine has complex dose related actions in prolactin secretion which may affect lactation.

    Neonates, infants born prematurely, those with low birth weight, those with an unstable gastrointestinal function or who have serious illnesses may require special consideration. For any infant, if a drug is prescribed to the nursing mother, it should be at the lowest practical dose and for the shortest time. When drug administration is unavoidable and breastfeeding is to continue, minimisation of exposure of the infant to the drug may sometimes be achieved by timing the maternal doses to just after a feeding episode. Infants exposed to drugs via breast milk should be monitored for unusual signs or symptoms. Interactions between the drug received by the infant from the mother's milk and medication prescribed for the infant should also be considered, for example, when the drug given to the infant may prevent metabolism of the drug received via breast milk.
    Specialist advice is available from the UK Drugs in Lactation Advisory Service at

    Side Effects

    Abnormal liver function tests
    Atrioventricular block
    Decreased lacrimation
    Disturbances in accommodation
    Dry mouth
    Dryness and irritation of eyes
    Dryness of nasal mucosa
    Elevated blood glucose (transient)
    Fluid retention
    Orthostatic hypotension
    Pain in parotid gland
    Pseudo-obstruction of the large intestine
    Raynaud's phenomenon
    Reduced libido
    Sinus bradycardia
    Sleep disturbances

    Withdrawal Symptoms and Signs

    Sudden withdrawal from treatment, especially those who have been receiving high doses may result in:
    Rebound hypertension
    Abdominal symptoms

    If these symptoms occur, they can usually be treated with reintroduction of clonidine or with alpha and beta blocking agents.


    It is strongly recommended that the UK National Poisons Information Service be consulted on cases of suspected or actual overdose where there is doubt over the degree of risk or about appropriate management.

    The following number will direct the caller to the relevant local centre (0844) 892 0111

    Information may be obtained if you have access to ToxBase the primary clinical toxicology database of the National Poisons Information Service. This is available via password on the internet ( ) or if this is unavailable at the backup site ( ).

    Further Information

    Last Full Review Date: May 2013

    Reference Sources

    Drugs During Pregnancy and Lactation: Treatment Options and Risk Assessment, 2nd edition (2007) ed. Schaefer, C., Peters, P. and Miller, R. Elsevier, London.

    Drugs in Pregnancy and Lactation: A Reference Guide to Fetal and Neonatal Risk, 9th edition (2011) ed. Briggs, G., Freeman, R. and Yaffe, S. Lippincott Williams & Wilkins, Philadelphia.

    Martindale: The Complete Drug Reference, 37th edition (2011) ed. Sweetman, S. Pharmaceutical Press, London.

    Medications and Mothers' Milk, 14th Edition (2010) Hale, T. Hale Publishing, Amarillo, Texas.

    Summary of Product Characteristics: Catapres Tablets 100 micrograms. Boehringer Ingelheim Ltd. Revised July 2014.

    The Renal Drug Handbook. 3rd edition. (2009) ed. Ashley, C and Currie, A. Radcliffe Medical Press, Abingdon.

    US National Library of Medicine. Toxicology Data Network. Drugs and Lactation Database (LactMed).
    Available at:
    Clonidine Last revised: April 3, 2012
    Last accessed: May 16, 2013

    NICE Evidence Services Available at: Last accessed: 17 August 2017

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