CLONIDINE (Catapres): What is used for?

What is Clonidine?

Clonidine (Clonidina) is a drug used to treat high blood pressure. The product ingredient is Clonidine hydrochloride (hcl).
The brand name of Clonidine in the United States is Catapres and Kapvay.

Mechanism of action (MOA) of Clonidine

It acts on the CNS, resulting in a reduction in sympathetic efferences and a decrease in peripheral resistance, renal vascular resistance, heart rate and blood pressure.

Therapeutic indications, uses and benefits of Clonidine

High Blood Pressure.

Dosage of Clonidine

Average dose: 0,150 mg/12 h. Start with 0.150 mg at night and at 10-15 days 0.150 mg/12 h. If necessary, after 2-4 weeks, the dose can be increased until the desired response.

Contraindications of Clonidine

Hypersensitivity to clonidina, patients with severe bradyarrhythmia as a consequence of sinus node syndrome or second or third degree atrioventricular block.

Warnings and precautions with Clonidine

Renal insufficiency, mild or moderate bradyarrhythmia such as low sinus rhythm, cerebral or peripheral perfusion disorders, depression, polyneuropathy and constipation; cardiac insufficiency, severe coronary heart disease, monitor; do not discontinue treatment abruptly, dose should be gradually reduced within 2-4 days.
If long-term treatment with a beta-blocker has to be stopped, the latter should be gradually suppressed first and then clonidine.
Risk of decreased tearing.
Caution in children.

Kidney failure

Caution in kidney failure. Renal insufficiency requires a particularly meticulous adjustment of the dose according to the degree of renal impairment, which must be established accordingly:
– the individual antihypertensive response, which can suffer important variations in patients with R.I.
– the degree of renal impairment.
Thorough monitoring is required in both cases.

Interactions with Clonidine

  • Hypotension enhanced by: other hypotensives. May be useful therapeutically concomitant with diuretics, vasodilators, beta blockers, calcium antagonists and ACEi, but not in the case of alpha 1 blockers.
  • Hypotensive effect reduced by: neuroleptics with alpha-adrenergic blocking properties, tricyclic antidepressants, NSAIDs.
  • Power effect of: alcohol, SN depressants.
  • Power of bradycardiac rhythm alterations with: ß adrenergic receptor blockers or digitalic glycosides.
  • Substances with alpha-2 blocking properties, such as phentolamine or tolazoline, can dose dependently cancel out the effects that this medicine deploys through the alpha-2 receptor.


There are limited data regarding the use in pregnant women. As a precautionary measure, it is preferable to avoid the use during pregnancy.


Clonidine is excreted in breast milk. There are insufficient data on the effects  in newborns/children. Therefore, this medicine should not be used during lactation.

Effects on driving ability

No studies have been conducted on the effect on the ability to drive and use machines. Patients should be warned that they may experience undesirable effects such as dizziness, sedation, and disturbances of accommodation during treatment.

Because it produces sedation and drowsiness, patients should not drive or operate dangerous machinery until their response to this medicine is determined.

Adverse reactions and side effects of Clonidine

Depression, sleep disorders; dizziness, sedation, headache; orthostatic hypotension; dry mouth, constipation, nausea, vomiting, salivary gland pain; erectile dysfunction; fatigue.


Source: The content of this active ingredient has been written taking into account the clinical and molecular information of all medicines authorised and marketed in the United States under the Unique Ingredient Identifier (UNII) by the Substance Registration System (SRS) of the Food and Drug Administration (FDA) and the United States Pharmacopeia (USP).

In order to know in detail the information authorized by the FDA for each drug, you should consult the corresponding medication guide authorized by the FDA.


PubChem CID: 2803
NCI Thesaurus: C380

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