CATAPRES-TTS-3
Clinical safety rating
cautionComprehensive clinical and safety monograph for CATAPRES-TTS-3 (CATAPRES-TTS-3).
Clonidine is an alpha-2 adrenergic agonist that reduces sympathetic outflow from the central nervous system, resulting in decreased peripheral vascular resistance, decreased heart rate, and lowered blood pressure.
| Metabolism | Clonidine is extensively metabolized in the liver by cytochrome P450 enzymes (CYP2D6) to inactive metabolites; approximately 50% excreted unchanged in urine. |
| Excretion | Approximately 40-60% of the absorbed dose is excreted unchanged in urine. About 20-30% is eliminated as metabolites via bile and feces. Renal clearance accounts for 50-60% of total clearance. |
| Half-life | Terminal elimination half-life is 12-16 hours after oral administration; with transdermal delivery, the effective half-life is prolonged to 20-40 hours due to continued absorption from the skin depot. In renal impairment, half-life may extend to 40 hours or longer. |
| Protein binding | Approximately 30-40% bound to albumin and alpha1-acid glycoprotein. |
| Volume of Distribution | 2.9-4.5 L/kg, indicating extensive distribution into tissues including the central nervous system. |
| Bioavailability | Transdermal system: Comparable to oral, approximately 50-80% of the dose reaches systemic circulation, with reduced peak-trough fluctuations. Oral: 70-80% (first-pass metabolism reduces bioavailability to ~40% in some individuals). |
| Onset of Action | Transdermal system: Therapeutic effect (antihypertensive) begins 2-3 days after initial application, as steady-state concentrations are achieved. Oral (immediate release): 30-60 minutes. IV: 5-10 minutes. |
| Duration of Action | Transdermal system: Duration is 7 days per patch. After removal, blood levels decline slowly over 8-12 hours. Oral: 6-8 hours. IV: 2-4 hours for blood pressure reduction. |
| Molecular Weight | 230.09 |
Transdermal patch: 0.3 mg/day applied once every 7 days; initial dose 0.1 mg/day, titrate weekly by 0.1 mg/day increments to desired response.
| Dosage form | SYSTEM |
| Renal impairment | For GFR 10-50 mL/min: reduce initial dose to 0.1 mg/day; for GFR <10 mL/min: use 0.1 mg/day and adjust cautiously, dosing interval may be extended to every 14 days; not dialyzable. |
| Liver impairment | No specific Child-Pugh based recommendations; use with caution in severe hepatic impairment due to possible accumulation; monitor for hypotension and bradycardia. |
| Pediatric use | Safety and efficacy not established; use not recommended in pediatric patients. |
| Geriatric use | Initiate at 0.1 mg/day; titrate slowly due to increased sensitivity and risk of hypotension; monitor for dizziness, syncope, and renal function declines. |
| 1st trimester | Clonidine is not recommended in the first trimester due to lack of adequate studies; animal studies have shown some teratogenic effects at high doses, but no well-controlled human studies are available. |
| 2nd trimester | Use only if clearly needed; monitor blood pressure closely. May cause fetal bradycardia or hypotension. |
| 3rd trimester | Use with caution; may cause neonatal bradycardia, hypotension, or withdrawal symptoms (irritability, jitteriness) in the newborn. |
Clinical note
Comprehensive clinical and safety monograph for CATAPRES-TTS-3 (CATAPRES-TTS-3).
| Placental transfer | Clonidine crosses the placenta readily, with cord blood concentrations approximately 50-60% of maternal serum levels. |
| Breastfeeding | Clonidine is excreted into human milk at concentrations approximately 50-60% of maternal serum levels. Monitor infant for signs of sedation, bradycardia, or hypotension. Caution in premature infants or those with renal impairment. |
| Lactation Rating | L3 (Moderately Safe) |
| Teratogenic Risk | First trimester: No evidence of major congenital malformations in human studies; avoid use unless benefit outweighs risk. Second and third trimesters: Associated with decreased placental perfusion and fetal growth restriction; may cause fetal bradycardia, hypotension, and hypoxia. Discontinue or reduce dose if fetal distress occurs. |
| Fetal Monitoring | Monitor maternal blood pressure and heart rate; fetal heart rate and growth via ultrasound; assess for signs of placental insufficiency; consider fetal non-stress testing in third trimester. |
| Fertility Effects | Clonidine may impair fertility in females by altering reproductive hormone levels and affecting ovulation; effects are reversible upon discontinuation. Male fertility not significantly affected. |
■ FDA Black Box Warning
None
| Serious Effects |
Hypersensitivity to clonidine or any patch componentNoncompliant patients or those unable to remove patch in case of emergencySevere bradycardia or sick sinus syndrome (without pacemaker)Concomitant use with other negative chronotropes may cause profound bradycardia
| Precautions | Rebound hypertension upon abrupt discontinuation (dose tapering required), CNS depression (sedation, dizziness), Bradycardia and heart block (use caution with conduction abnormalities), Orthostatic hypotension, Renal impairment (dose adjustment needed), Contraindicated in patients with severe bradycardia or sick sinus syndrome |
| Food/Dietary | No specific food interactions. Limit alcohol intake as it may potentiate hypotensive and sedative effects. |
| Clinical Pearls | Catapres-TTS-3 (clonidine transdermal system) delivers 0.3 mg/day. Apply to hairless, intact skin on upper arm or torso. Rotate site weekly to minimize local irritation. Do not cut or trim patch. If patch falls off, replace with new patch. Onset of action delayed ~2-3 days after first application; oral clonidine may be needed initially. Contraindicated in patients with history of hypersensitivity to clonidine. Use cautiously in severe coronary insufficiency, recent MI, cerebrovascular disease, or chronic renal failure. Rebound hypertension may occur if patch is removed abruptly; taper over 2-4 days if discontinuing. May cause dry mouth, drowsiness, dizziness, constipation, and orthostatic hypotension. |
| Patient Advice | Apply patch once every 7 days to a clean, dry, hairless area of skin on the upper arm or torso. · Do not cut or trim the patch; use a new patch if it falls off. · Rotate application site weekly to prevent skin irritation. · Avoid applying patch to irritated or scarred skin. · Do not stop using the patch without talking to your doctor; abruptly stopping can cause a dangerous rise in blood pressure. · If you have surgery, inform your surgeon you are using this patch. · Side effects may include dry mouth, drowsiness, dizziness, and constipation. Avoid driving or hazardous activities until you know how the patch affects you. · Alcohol can increase drowsiness and dizziness; limit alcohol consumption. |
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