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. |
| Molecular Weight | 234.34 |
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 | Avoid use; lidocaine crosses placenta and may cause fetal bradycardia. Limited data in first trimester; potential for teratogenic effects not fully established. |
| 2nd trimester | Use only if clearly needed; monitor fetal heart rate. Lidocaine use in second trimester associated with transient fetal heart rate decelerations. |
| 3rd trimester | Use cautiously near term; lidocaine may accumulate in fetus and cause neonatal CNS depression. Avoid in cases of fetal distress or prematurity. |
Clinical note
Comprehensive clinical and safety monograph for ORABLOC (ORABLOC).
| Placental transfer | Lidocaine readily crosses the placenta by passive diffusion; fetal concentrations reach about 50-60% of maternal levels. Protein binding in fetal plasma is lower, increasing free drug exposure. |
| Breastfeeding | Lidocaine is excreted into breast milk in small amounts (milk:plasma ratio ~0.4). Oral bioavailability in infants is low; however, if used repeatedly or in high doses, monitor infant for drowsiness, poor feeding, or irritability. Use with caution in breastfeeding mothers of neonates or preterm infants. |
■ FDA Black Box Warning
None.
| Serious Effects |
Hypersensitivity to lidocaine or amide-type anestheticsSevere hypovolemia or shockThird-degree atrioventricular block without pacemakerAdams-Stokes syndromeSevere sinoatrial block
| 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) |
| Food/Dietary | No known food interactions. |
| Clinical Pearls |
Loading safety data…
| Lactation Rating | L2 (Safer) |
| 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. |
| 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. |
| ORABLOC (lidocaine/prilocaine topical cream) requires application under occlusion for at least 60 minutes for effective dermal analgesia; onset is delayed in thick skin (e.g., palms/soles). Avoid use on mucous membranes or broken skin due to risk of systemic absorption. In patients with G6PD deficiency or methemoglobin reductase deficiency, monitor for methemoglobinemia, especially in infants. Use minimum amount to cover intended area; not for use in children <1 year or those taking class III antiarrhythmics (e.g., amiodarone). |
| Patient Advice | Apply a thick layer of cream to intact skin and cover with an occlusive dressing; do not rub in. · Leave on for at least 1 hour before procedure, but not more than 4 hours total. · Do not use on broken skin, eyes, mouth, or genital area. · Remove cream and dressing immediately before the procedure; do not wash off. · Possible side effects include temporary skin paleness, redness, or mild swelling; rarely, bluish skin or fatigue may indicate methemoglobinemia. · Keep out of reach of children and do not reuse leftover cream. · Inform healthcare provider if taking medications for irregular heartbeat, sulfa drugs, or have enzyme deficiencies. |