Catapresan - General Information
An alpha-2 adrenergic agonist that crosses the blood-brain barrier. Catapresan acts centrally by reducing sympathetic tone, resulting in a fall in diastolic and systolic blood pressure and a reduction in heart rate. It also acts peripherally, and this peripheral activity may be responsible for the transient increase in blood pressure seen during rapid intravenous administration. (From Martindale, the Extra Pharmacopoeia, 30th ed, p350)
Pharmacology of Catapresan
Catapresan is an antihypertensive agent and an epidural agent for refractory cancer pain. Similar to guanabenz in mechanism of action, clonidine is used in the treatment of hypertension, opiate and nicotine withdrawal, vascular headaches, diabetic diarrhea, glaucoma, ulcerative colitis, Gilles de la Tourette's syndrome, menopause symptoms, severe pain in cancer patients refractory to opiate agonists, and neuropathic pain and in the diagnosis of pheochromocytoma.
Catapresan for patients
Patients who engage in potentially hazardous activities, such as operating machinery or driving, should be advised of a potential sedative effect of clonidine. Patients should be cautioned against interruption of clonidine hydrochloride therapy without a physician's advice.
Patients should be instructed about the risks of rebound hypertension and warned not to discontinue clonidine except under the supervision of a physician. Patients should notify their physician immediately if clonidine administration is inadvertently interrupted for any reason. Patients who engage in potentially hazardous activities, such as operating machinery or driving, should be advised of the potential sedative and hypotensive effects of epidural clonidine. They should also be informed that sedative effects may be increased by CNS-depressing drugs such as alcohol and barbiturates, and that hypotensive effects may be increased by opiates.
If a patient receiving clonidine hydrochloride is also taking tricyclic antidepressants, the effect of clonidine may be reduced, thus necessitating an increase in dosage. Clonidine hydrochloride may enhance the CNS-depressive effects of alcohol, barbiturates or other sedatives. Amitriptyline in combination with clonidine enhances the manifestation of corneal lesions in rats
Clonidine may potentiate the CNS-depressive effect of alcohol, barbiturates or other sedating drugs. Narcotic analgesics may potentiate the hypotensive effects of clonidine. Tricyclic antidepressants may antagonize the hypotensive effects of clonidine. The effects of tricyclic antidepressants on clonidine's analgesic actions are not known.
Beta blockers may exacerbate the hypertensive response seen with clonidine withdrawl. Also, due to the potential for additive effects such as bradycardia and AV block, caution is warranted in patients receiving clonidine with agents known to affect sinus node function or AV nodal conduction (e.g., digitalis, calcium channel blockers, and beta-blockers.)
There is one reported case of a patient with acute delirium associated with the simultaneous use of fluphenazine and oral clonidine. Symptoms resolved when clonidine was withdrawn and recurred when the patient was rechallenged with clonidine.
Epidural clonidine may prolong the duration of pharmacologic effects of epidural local anesthetics, including both sensory and motor blockade.
Clonidine HCl is contraindicated in patients with a history of sensitization or allergic reactions to clonidine. Epidural administration is contraindicated in the presence of an injection site infection, in patients on anticoagulant therapy, and in those with a bleeding diathesis. Administration of epidural clonidine HCl above the C4 dermatome is contraindicated since there are no adequate data to support such use
Additional information about Catapresan
Catapresan Indication: For the treatment of hypertension and maybe used in prophylaxis of migraine or recurrent vascular headache; Menopausal flushing
Mechanism Of Action: Catapresan acts as an agonist at presynaptic alpha(2)-receptors in the nucleus tractus solitarius of the medulla oblongata. Stimulation of these receptors results in the supression of efferent sympathetic pathways and the subsequent decrease in blood pressure and vascular tone in the heart, kidneys, and peripheral vasculature. Catapresan is also a partial agonist at presynaptic alpha(2)-adrenergic receptors of peripheral nerves in vascular smooth muscle.
Drug Interactions: Acebutolol Increased hypertension when clonidine stopped
Amitriptyline The tricyclic decreases the effect of clonidine
Amoxapine The tricyclic decreases the effect of clonidine
Atenolol Increased hypertension when clonidine stopped
Betaxolol Increased hypertension when clonidine stopped
Bevantolol Increased hypertension when clonidine stopped
Bisoprolol Increased hypertension when clonidine stopped
Carteolol Increased hypertension when clonidine stopped
Carvedilol Increased hypertension when clonidine stopped
Clomipramine The tricyclic decreases the effect of clonidine
Desipramine The tricyclic decreases the effect of clonidine
Doxepin The tricyclic decreases the effect of clonidine
Imipramine The tricyclic decreases the effect of clonidine
Nortriptyline The tricyclic decreases the effect of clonidine
Esmolol Increased hypertension when clonidine stopped
Labetalol Increased hypertension when clonidine stopped
Metoprolol Increased hypertension when clonidine stopped
Mirtazapine Possible hypertensive crisis
Nadolol Increased hypertension when clonidine stopped
Penbutolol Increased hypertension when clonidine stopped
Pindolol Increased hypertension when clonidine stopped
Practolol Increased hypertension when clonidine stopped
Propranolol Increased hypertension when clonidine stopped
Sotalol Increased hypertension when clonidine stopped
Timolol Increased hypertension when clonidine stopped
Protriptyline The tricyclic decreases the effect of clonidine
Trimipramine The tricyclic decreases the effect of clonidine
Oxprenolol Increased hypertension when clonidine stopped
Food Interactions: Take without regard to meals.
Generic Name: Clonidine
Synonyms: Clonidinum [Inn-Latin]; Clonidinhydrochlorid; Clonidine HCl; Clonidin; Chlornidinum; ST 155BS
Drug Category: Sympatholytics; Antihypertensive Agents; Analgesics; Central Alpha-Agonists
Drug Type: Small Molecule; Approved
Other Brand Names containing Clonidine: Adesipress; Catapres; Catapres-TTS; Catapresan; Catapressan; Catarpres; Catarpresan; Clonistada; Dixarit; Duraclon; Duraclont; Ipotensium; Isoglaucon; Tenso-Timelets;
Absorption: Well absorbed following oral administration. Bioavailability following chronic administration is approximately 65%.
Toxicity (Overdose): Oral LD50 is 150 mg/kg in rat and 30 mg/kg in dog. Symptoms of overdose include constriction of pupils of the eye, drowsiness, high blood pressure followed by a drop in pressure, irritability, low body temperature, slowed breathing, slowed heartbeat, slowed reflexes, and weakness.
Protein Binding: 20-40%
Biotransformation: Hepatic. Metabolized through minor pathways. The major metabolite, p-hydroxyclonidine, is present in concentrations less than 10% of those of unchanged clonidine in urine.
Half Life: 12-16 hours
Dosage Forms of Catapresan: Tablet Oral
Chemical IUPAC Name: N-(2,6-dichlorophenyl)-4,5-dihydro-1H-imidazol-2-amine
Chemical Formula: C9H9Cl2N3
Clonidine on Wikipedia: https://en.wikipedia.org/wiki/Clonidine
Organisms Affected: Humans and other mammals