ZTLIDO
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ZTLIDO (ZTLIDO).
ZTLIDO (lidocaine) is a sodium channel blocker that binds to voltage-gated sodium channels in neuronal membranes, stabilizing the membrane and inhibiting the initiation and conduction of nerve impulses, thereby producing local anesthesia.
| Metabolism | Primarily metabolized in the liver via cytochrome P450 enzymes (CYP1A2, CYP3A4) to active metabolites (monoethylglycinexylidide, glycinexylidide). |
| Excretion | Primarily renal excretion as unchanged drug (80-85%) and metabolites (10-15%); less than 5% excreted in feces. |
| Half-life | Terminal elimination half-life is 1.5 to 2.0 hours in patients with normal renal function; prolonged in renal impairment (up to 6-8 hours with CrCl <30 mL/min). |
| Protein binding | 70-80% bound to albumin; minor binding to alpha-1-acid glycoprotein. |
| Volume of Distribution | Vd approximately 0.5-0.7 L/kg, indicating distribution into total body water and extensive tissue binding. |
| Bioavailability | Intramuscular: 100% bioavailability; Oral: not available. |
| Onset of Action | Intravenous: 2-4 minutes; Intramuscular: 10-15 minutes. |
| Duration of Action | Intravenous: 15-20 minutes; Intramuscular: 30-60 minutes. Duration is dose-dependent and may be prolonged with higher doses or hepatic impairment. |
1.8% lidocaine topical patch: Apply up to 3 patches at once to intact skin for up to 12 hours in a 24-hour period.
| Dosage form | PATCH |
| Renal impairment | No dose adjustment required for lidocaine patches; systemic absorption is minimal. |
| Liver impairment | Use with caution in severe hepatic impairment (Child-Pugh C); monitor for lidocaine toxicity due to reduced metabolism. |
| Pediatric use | Safety and efficacy not established in pediatric patients under 18 years; not recommended. |
| Geriatric use | No specific dose adjustment; use with caution due to potential for increased systemic absorption, reduced clearance, and increased sensitivity to adverse effects. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for ZTLIDO (ZTLIDO).
| Breastfeeding | Lidocaine is excreted into breast milk in small amounts; the milk-to-plasma (M/P) ratio is approximately 0.4. The relative infant dose via breast milk is estimated to be <4% of the maternal weight-adjusted dose. Lidocaine is considered compatible with breastfeeding when used cautiously; monitor the infant for sedation, poor feeding, or apnea. |
| Teratogenic Risk | ZTLIDO (lidocaine transdermal patch) is classified as FDA Pregnancy Category B. Animal reproduction studies have not revealed evidence of fetal harm, but there are no adequate and well-controlled studies in pregnant women. Lidocaine crosses the placenta but is rapidly metabolized by the fetus. Risk during first trimester is considered low; however, use during labor and delivery (third trimester) may cause maternal hypotension, fetal bradycardia, or neonatal CNS depression. Avoid use near the cervix or in large amounts. |
■ FDA Black Box Warning
None
| Serious Effects |
["Hypersensitivity to lidocaine or any component of the product","Application over broken or inflamed skin","Known history of porphyria"]
| Precautions | ["Risk of methemoglobinemia, particularly with higher doses or in patients with glucose-6-phosphate dehydrogenase deficiency","Cardiovascular effects: bradycardia, hypotension, arrhythmias; use caution in patients with heart block or severe heart failure","Neurologic toxicity: seizures, CNS depression; dose-related","Use caution in patients with hepatic impairment due to reduced metabolism"] |
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| Fetal Monitoring | No specific monitoring is routinely required. However, if using during labor, monitor fetal heart rate and maternal blood pressure. In case of systemic absorption, monitor for CNS and cardiovascular toxicity. Patch should be removed prior to delivery if used near incision or operative site. |
| Fertility Effects | No human data on fertility effects. Animal studies have not shown impaired fertility. Based on mechanism, it is unlikely to affect fertility when used as directed. |