Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
CATAPRES-TTS-1 vs CATAPRES-TTS-3
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Alpha-2 adrenergic agonist that reduces sympathetic outflow from the CNS, leading to decreased peripheral vascular resistance and blood pressure.
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.
Hypertension (FDA-approved),Off-label: attention deficit hyperactivity disorder (ADHD), opioid withdrawal, menopausal hot flashes, migraine prophylaxis, anxiety disorders
Hypertension (first-line treatment),Off-label: Attention deficit hyperactivity disorder (ADHD), management of opioid withdrawal, menopausal flushing, diabetic diarrhea, migraine prophylaxis
Clonidine transdermal system 0.1 mg/24 hours applied to intact skin on upper arm or chest once every 7 days. Titrate based on response, maximum 0.3 mg/24 hours.
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.
12-16 hours; may be prolonged in renal impairment (up to 40 hours).
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.
Hepatic metabolism via CYP2D6 and other pathways; approximately 50% metabolized in the liver, with the remainder excreted unchanged in urine.
Clonidine is extensively metabolized in the liver by cytochrome P450 enzymes (CYP2D6) to inactive metabolites; approximately 50% excreted unchanged in urine.
Renal: 40-60% unchanged; biliary/fecal: ~20% as metabolites; remainder metabolized.
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.
20-40% bound to albumin.
Approximately 30-40% bound to albumin and alpha1-acid glycoprotein.
2.1-4.0 L/kg; indicates extensive tissue distribution.
2.9-4.5 L/kg, indicating extensive distribution into tissues including the central nervous system.
Transdermal: ~60% compared to oral; oral: ~100% but extensive first-pass.
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).
For GFR 10-50 m L/min: reduce dose by 50% and monitor. For GFR <10 m L/min: reduce dose by 75%. Not recommended in dialysis patients due to poor efficacy.
For GFR 10-50 m L/min: reduce initial dose to 0.1 mg/day; for GFR <10 m L/min: use 0.1 mg/day and adjust cautiously, dosing interval may be extended to every 14 days; not dialyzable.
No specific Child-Pugh based guidelines. Use with caution in severe hepatic impairment due to increased risk of hypotension and bradycardia.
No specific Child-Pugh based recommendations; use with caution in severe hepatic impairment due to possible accumulation; monitor for hypotension and bradycardia.
Not recommended for children <12 years. For adolescents >12 years, apply 0.1 mg/24 hours patch weekly; adjust based on response.
Safety and efficacy not established; use not recommended in pediatric patients.
Start with lowest dose (0.1 mg/24 hours) due to increased sensitivity to hypotensive effects. Monitor for orthostatic hypotension and CNS effects.
Initiate at 0.1 mg/day; titrate slowly due to increased sensitivity and risk of hypotension; monitor for dizziness, syncope, and renal function declines.
None
None
Rebound hypertension on abrupt discontinuation (especially with high doses),Use with caution in patients with cerebrovascular disease, renal impairment, or history of depression,May require dose adjustment in renal impairment,Risk of hypotension, bradycardia, and sedation
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
Known hypersensitivity to clonidine or any component of the transdermal system,Concurrent use with other alpha-2 agonists (e.g., tizanidine) may cause additive effects
Hypersensitivity to clonidine or any component of the patch,History of severe bradycardia or sick sinus syndrome
Avoid excessive alcohol consumption, as it may potentiate the hypotensive and sedative effects of clonidine. Limit or avoid grapefruit juice, as it can alter drug metabolism. No specific food restrictions; maintain a balanced diet low in sodium to help control blood pressure. Caffeine may counteract the antihypertensive effect; advise moderate consumption.
No specific food interactions. Limit alcohol intake as it may potentiate hypotensive and sedative effects.
First trimester: No evidence of increased risk of major malformations from human data; animal studies show no teratogenicity at clinically relevant doses. Second and third trimesters: Exposure associated with reduced placental perfusion and fetal growth restriction; neonatal withdrawal syndrome including hyperirritability, tremors, and respiratory depression reported with third trimester use.
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.
Clonidine is excreted into breast milk with a milk-to-plasma ratio of approximately 1.5; limited data, but risk of infant hypotension and sedation; use only if benefit outweighs risk; monitor infant for bradycardia, somnolence, and feeding difficulties.
Clonidine is excreted into breast milk; M/P ratio approximately 1.5:1. Limited data on infant effects; potential for infant hypotension, bradycardia, and sedation. Use with caution and monitor infant for adverse effects.
No standard dose adjustment recommended for pregnancy; pharmacokinetic changes (increased volume of distribution, enhanced renal clearance) may require dose titration based on clinical response; avoid abrupt discontinuation to prevent rebound hypertension.
Increased plasma volume and renal clearance in pregnancy may require dose adjustment; empirical dose reduction in third trimester is not recommended; titrate to achieve optimal blood pressure control while avoiding maternal hypotension and fetal compromise.
Clonidine transdermal (Catapres-TTS-1) is indicated for hypertension. Apply to a hairless, intact area of skin on the upper arm or torso, rotating sites to minimize irritation. Avoid abrupt discontinuation to prevent rebound hypertension. Onset of therapeutic effect is delayed 2-3 days after initial application; consider overlapping oral therapy during titration. The patch may be less effective in patients with extensive sweating or during fever.
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.
Apply the patch to a clean, dry, hairless area of skin, such as the upper arm or chest. Rotate application sites with each new patch to avoid skin irritation.,Replace the patch every 7 days to maintain consistent blood pressure control. Do not cut the patch or apply over cuts, scars, or irritated skin.,Do not stop using this medication abruptly, as this can cause a dangerous rise in blood pressure (rebound hypertension). Follow your doctor's instructions for discontinuing therapy.,If the patch falls off, apply a new one to a different skin site. If you forget to change the patch, do so as soon as you remember and adjust your schedule accordingly.,Avoid alcohol, as it may increase the sedative effects of this medication. Limit or avoid consuming grapefruit juice, as it may affect how the drug works.,Monitor your blood pressure regularly and report any persistent dizziness, dry mouth, or skin rash at the patch site to your healthcare provider.,Keep the patch away from heat sources (such as heating pads, saunas, or direct sunlight) as heat can increase the release of the medication and cause overdose symptoms.
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.
No interactions on record
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about CATAPRES-TTS-1 vs CATAPRES-TTS-3, answered by our medical review team.
CATAPRES-TTS-1 is a Central Alpha-Agonist that works by Alpha-2 adrenergic agonist that reduces sympathetic outflow from the CNS, leading to decreased peripheral vascular resistance and blood pressure.. CATAPRES-TTS-3 is a Central Alpha-Agonist that works by 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.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between CATAPRES-TTS-1 and CATAPRES-TTS-3 depend on the specific clinical indication. These are both Central Alpha-Agonist agents and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of CATAPRES-TTS-1 is: Clonidine transdermal system 0.1 mg/24 hours applied to intact skin on upper arm or chest once every 7 days. Titrate based on response, maximum 0.3 mg/24 hours.. The standard adult dose of CATAPRES-TTS-3 is: 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.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between CATAPRES-TTS-1 and CATAPRES-TTS-3 in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. CATAPRES-TTS-1 is classified as Category C. First trimester: No evidence of increased risk of major malformations from human data; animal studies show no teratogenicity at clinically relevant doses. Second and third trimeste. CATAPRES-TTS-3 is classified as Category C. First trimester: No evidence of major congenital malformations in human studies; avoid use unless benefit outweighs risk. Second and third trimesters: Associated with decreased pla. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.