ONYDA XR
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ONYDA XR (ONYDA XR).
Clonidine is a central alpha-2 adrenergic agonist that stimulates alpha-2 adrenergic receptors in the brainstem, reducing sympathetic outflow from the CNS, resulting in decreased peripheral resistance, renal vascular resistance, heart rate, and blood pressure.
| Metabolism | Clonidine is metabolized primarily in the liver via cytochrome P450 (CYP) enzymes, mainly CYP2D6, to inactive metabolites. |
| Excretion | Primarily renal (60–70% as unchanged drug) and biliary/fecal (20–30% as metabolites). |
| Half-life | Terminal elimination half-life of 28–35 hours; accumulation occurs with daily dosing, reaching steady state in 5–7 days. |
| Protein binding | 99% bound to plasma proteins (primarily alpha-1-acid glycoprotein and albumin). |
| Volume of Distribution | Vd approximately 3–4 L/kg, indicating extensive extravascular distribution and tissue binding. |
| Bioavailability | Oral: 100% (immediate-release); extended-release (ONYDA XR): 87% relative to immediate-release due to first-pass metabolism. |
| Onset of Action | Oral: 30–60 minutes to detectable plasma levels; clinical effect (e.g., pain relief) within 1–2 hours. |
| Duration of Action | Duration of analgesic effect: 8–12 hours; extended-release formulation provides sustained plasma levels for 24 hours with once-daily dosing. |
Onyda XR (clonidine hydrochloride extended-release tablets) 0.17 mg orally once daily at bedtime.
| Dosage form | SUSPENSION, EXTENDED RELEASE |
| Renal impairment | For GFR <30 mL/min, initiate at 0.17 mg once daily; titrate cautiously. Not studied in dialysis. |
| Liver impairment | No specific adjustment in Child-Pugh A or B; use caution in severe impairment (Child-Pugh C). |
| Pediatric use | Not Approved for pediatric patients; safety and efficacy not established. |
| Geriatric use | Start at low end of dosing range (0.17 mg) due to increased sensitivity and renal function decline. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for ONYDA XR (ONYDA XR).
| Breastfeeding | Clonidine is excreted in human milk with a milk-to-plasma ratio of approximately 1.5. Concentrations in breast milk can be up to 3 times maternal plasma levels. Use with caution; monitor infant for hypotension, bradycardia, and sedation. |
| Teratogenic Risk | FDA Pregnancy Category C. First trimester: limited data; animal studies show fetal abnormalities at high doses. Second/third trimester: risk of premature closure of fetal ductus arteriosus and oligohydramnios due to NSAID component (clonidine is not a major teratogen). Avoid after 30 weeks gestation. |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
["Hypersensitivity to clonidine","Severe bradycardia or sick sinus syndrome (without pacemaker)"]
| Precautions | ["Rebound hypertension upon abrupt discontinuation","Central nervous system depression (drowsiness, sedation)","Bradycardia and heart block","Orthostatic hypotension","Use with caution in patients with severe coronary insufficiency, recent myocardial infarction, cerebrovascular disease, or chronic renal failure"] |
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| Fetal Monitoring |
| Monitor maternal blood pressure and heart rate regularly. Fetal ultrasound for amniotic fluid index and ductus arteriosus patency if used beyond 20 weeks. Assess fetal growth and well-being. |
| Fertility Effects | Clonidine may impair fertility in males and females based on animal studies (altered reproductive cycles, decreased sperm count). Human data are limited. |