Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
CATAPRES vs CATAPRES-TTS-1
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Selective alpha-2 adrenergic agonist that reduces sympathetic outflow from the central nervous system, resulting in decreased peripheral vascular resistance and lowered blood pressure.
Alpha-2 adrenergic agonist that reduces sympathetic outflow from the CNS, leading to decreased peripheral vascular resistance and blood pressure.
Hypertension,Attention deficit hyperactivity disorder (ADHD) - off-label,Anxiety - off-label,Opioid withdrawal - off-label,Migraine prophylaxis - off-label
Hypertension (FDA-approved),Off-label: attention deficit hyperactivity disorder (ADHD), opioid withdrawal, menopausal hot flashes, migraine prophylaxis, anxiety disorders
Oral: 0.1 mg twice daily initially, titrate to 0.2-0.6 mg/day in divided doses; maximum 2.4 mg/day. Transdermal: 0.1 mg/24 hours patch applied every 7 days, titrate to 0.2-0.3 mg/24 hours.
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.
Terminal elimination half-life: 12-16 hours in normal renal function; prolonged to 48-96 hours in severe renal impairment. Use with caution in CKD.
12-16 hours; may be prolonged in renal impairment (up to 40 hours).
Extensively metabolized in the liver via cytochrome P450 enzymes, primarily CYP2D6, with about 50% undergoing first-pass metabolism.
Hepatic metabolism via CYP2D6 and other pathways; approximately 50% metabolized in the liver, with the remainder excreted unchanged in urine.
Renal: ~65% (40-50% unchanged; 20-25% as metabolites). Biliary/fecal: ~35% (conjugated metabolites).
Renal: 40-60% unchanged; biliary/fecal: ~20% as metabolites; remainder metabolized.
20-40% bound to albumin and alpha-1-acid glycoprotein (AAG).
20-40% bound to albumin.
Vd: 2.1-4.0 L/kg. Distribution widely into tissues including CNS; high Vd reflects extensive extravascular distribution.
2.1-4.0 L/kg; indicates extensive tissue distribution.
Oral: 75-95% (immediate release). Transdermal: ~60% relative to oral (dose-adjusted).
Transdermal: ~60% compared to oral; oral: ~100% but extensive first-pass.
Cr Cl 10-30 m L/min: reduce dose by 50% or extend interval. Cr Cl <10 m L/min: administer 25-50% of usual dose. Not significantly removed by hemodialysis.
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.
Child-Pugh Class B or C: reduce dose by 50% and monitor for hypotension; titrate slowly due to reduced clearance.
No specific Child-Pugh based guidelines. Use with caution in severe hepatic impairment due to increased risk of hypotension and bradycardia.
Oral: Initial 5-10 mcg/kg/day divided every 8-12 hours; titrate to 15-25 mcg/kg/day; maximum 0.9 mg/day.
Not recommended for children <12 years. For adolescents >12 years, apply 0.1 mg/24 hours patch weekly; adjust based on response.
Start with lowest dose (0.05 mg twice daily) due to increased sensitivity; avoid abrupt discontinuation; monitor for orthostatic hypotension and CNS depression.
Start with lowest dose (0.1 mg/24 hours) due to increased sensitivity to hypotensive effects. Monitor for orthostatic hypotension and CNS effects.
No FDA black box warning.
None
Rebound hypertension upon abrupt discontinuation,Sedation and dizziness,Bradycardia and heart block,Dry mouth and constipation,Use with caution in renal impairment,May mask signs of hypoglycemia
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
Hypersensitivity to clonidine,Concurrent use with monoamine oxidase inhibitors (MAOIs),Severe bradycardia or sick sinus syndrome without pacemaker
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
Avoid excessive alcohol consumption as it may potentiate the hypotensive effects and increase sedation.
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.
Clonidine (CATAPRES) crosses the placenta. First trimester: No clear evidence of major congenital malformations; limited data. Second and third trimesters: May cause decreased fetal heart rate variability and transient neonatal hypertension, bradycardia, and jitteriness. Risk for rebound maternal hypertension if discontinued abruptly.
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.
Clonidine is excreted into breast milk with M/P ratio approximately 1.4-2.0. Relative infant dose is about 2-4% of maternal weight-adjusted dose. Caution in premature infants or those with renal impairment; monitor for sedation, hypotension, and apnea. Breastfeeding is generally considered compatible but weigh risks vs benefits.
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.
Increased plasma volume and renal clearance during pregnancy may reduce clonidine serum levels; monitor blood pressure and consider dose adjustment (increase if needed) to maintain normotension. Avoid abrupt discontinuation due to risk of rebound hypertension.
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.
Abrupt discontinuation can cause rebound hypertension. Monitor heart rate and blood pressure closely in patients with renal impairment. Can cause orthostatic hypotension, especially when combined with diuretics. Use with caution in patients with bradycardia or heart block. Transdermal patch may cause contact dermatitis; rotate sites. IV clonidine can be used for hypertensive emergencies.
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.
Do not stop taking this medication abruptly as it may cause a rapid increase in blood pressure.,Avoid driving or operating heavy machinery until you know how this medication affects you, as it may cause dizziness or drowsiness.,If you are using the patch, apply it to a hairless area of skin on the upper arm or chest and rotate sites to avoid skin irritation.,Rise slowly from sitting or lying down to prevent dizziness from low blood pressure.,Avoid alcohol as it can increase the side effects of this medication.
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.
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 vs CATAPRES-TTS-1, answered by our medical review team.
CATAPRES is a Central Alpha-Agonist that works by Selective alpha-2 adrenergic agonist that reduces sympathetic outflow from the central nervous system, resulting in decreased peripheral vascular resistance and lowered blood pressure.. 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.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between CATAPRES and CATAPRES-TTS-1 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 is: Oral: 0.1 mg twice daily initially, titrate to 0.2-0.6 mg/day in divided doses; maximum 2.4 mg/day. Transdermal: 0.1 mg/24 hours patch applied every 7 days, titrate to 0.2-0.3 mg/24 hours.. 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.. 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 and CATAPRES-TTS-1 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 is classified as Category C. Clonidine (CATAPRES) crosses the placenta. First trimester: No clear evidence of major congenital malformations; limited data. Second and third trimesters: May cause decreased feta. 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. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.