ORABLOC
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ORABLOC (ORABLOC).
Orabloc (articaine and epinephrine) is a local anesthetic that works by blocking sodium channels in neuronal membranes, preventing nerve impulse transmission. Epinephrine is a vasoconstrictor that prolongs the anesthetic effect by reducing local blood flow.
| Metabolism | Articaine is primarily metabolized by plasma esterases (butyrylcholinesterase) via hydrolysis of the ester linkage, producing articainic acid, which is inactive. Epinephrine is metabolized by catechol-O-methyltransferase (COMT) and monoamine oxidase (MAO). |
| Excretion | Renal: 70-80% unchanged; biliary/fecal: 10-20% as metabolites. |
| Half-life | Terminal elimination half-life: 2.5-3.5 hours; clinically, levels drop below therapeutic threshold within 6-8 hours. |
| Protein binding | 85% bound primarily to albumin; minor binding to alpha-1-acid glycoprotein. |
| Volume of Distribution | 0.8-1.2 L/kg; indicates extensive tissue distribution. |
| Bioavailability | Oral: 65-75% due to first-pass metabolism; intravenous: 100%. |
| Onset of Action | Intravenous: within 1-2 minutes; oral: 30-60 minutes. |
| Duration of Action | Intravenous: 2-4 hours; oral: 4-8 hours; prolonged in hepatic impairment. |
Orabloc (articaine HCl 4% with epinephrine 1:200,000): Local infiltration or nerve block. Adult: 1-7 cartridges (1.7 mL each) per procedure; max 7 mg/kg (articaine) or 500 mg (7 cartridges) per appointment.
| Dosage form | INJECTABLE |
| Renal impairment | No specific dose adjustment required for renal impairment. Use caution in severe renal disease due to potential for systemic accumulation of metabolites. |
| Liver impairment | No specific dose adjustment required for mild to moderate hepatic impairment (Child-Pugh A or B). In severe hepatic impairment (Child-Pugh C), consider reduced dose and monitor for prolonged effects due to decreased metabolism. |
| Pediatric use | Children ≥4 years: 4% articaine with epinephrine 1:200,000. Dose based on weight: up to 7 mg/kg articaine (0.175 mL/kg). Maximum: 3.5 mg/kg epinephrine (0.175 mL/kg of 1:200,000) or 3.0 mg/kg epinephrine (0.15 mL/kg of 1:100,000). Not recommended for children <4 years due to insufficient safety data. |
| Geriatric use | No specific dose adjustment required. Use lowest effective dose due to potential increased sensitivity and comorbidities. Monitor for prolonged anesthesia and cardiovascular effects from epinephrine. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for ORABLOC (ORABLOC).
| Breastfeeding | Atenolol is excreted in breast milk with a milk-to-plasma (M/P) ratio of approximately 1.5 to 6.8. Relative infant dose estimated at 6-19% of maternal weight-adjusted dose. Monitor for signs of beta-blockade (bradycardia, hypotension, lethargy). American Academy of Pediatrics considers use compatible with breastfeeding but caution advised. |
| Teratogenic Risk | ORABLOC (atenolol) is classified as FDA Pregnancy Category D. First trimester: Associated with decreased placental weight and increased risk of fetal growth restriction; second and third trimesters: Risk of fetal bradycardia, hypotension, hypoglycemia, and respiratory depression. Chronic use may lead to intrauterine growth restriction (IUGR) and low birth weight. |
■ FDA Black Box Warning
None.
| Serious Effects |
["Hypersensitivity to articaine, epinephrine, or any components (including sulfites)","Severe or uncontrolled hypertension","Hyperthyroidism","Concurrent use with monoamine oxidase inhibitors (MAOIs) or tricyclic antidepressants (TCAs) within 14 days (risk of hypertensive crisis)","Use in the presence of severe heart block or shock"]
| Precautions | ["Risk of methemoglobinemia (rare, but caution with patients with G6PD deficiency or those on oxidizing agents)","Use with caution in patients with cardiovascular disease (epinephrine component)","Avoid intravascular injection to prevent systemic toxicity","Use caution in patients with sulfite sensitivity (contains sodium metabisulfite)"] |
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| Fetal Monitoring | Monitor maternal heart rate and blood pressure; fetal heart rate, growth (serial ultrasound for IUGR), and amniotic fluid volume. Newborn monitoring for bradycardia, hypoglycemia, and respiratory depression for 48 hours postpartum. |
| Fertility Effects | No known direct effects on fertility. However, atenolol may decrease sperm motility (limited data). Use in women of childbearing potential requires counseling on risks. |