Prilocaine

CITANEST

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Prilocaine ballicule: receptor binding, kinetics and half-life diagram — Mechanism of action: Prilocaine ballicule

What it isAmide local anesthetic; dental and topical anesthesia, and part of EMLA.

Why this oneLess cardiotoxic than the other amides and effective in the eutectic topical mixture on intact skin.

What limits itIts metabolite causes methemoglobinemia, so it is avoided in infants and in G6PD deficiency.

Prilocaine molecular structure (skeletal formula) — Molecular structure: Prilocaine

FDA-approved for

local anesthesia (1965)

FDA label

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FDA dosing	Population	Start	Target	Max
Dental local anesthesia (infiltration or nerve block) — 4% injection	Adult	1-2 mL (40-80 mg) usually adequate per procedure	Least volume giving effective anesthesia	<70 kg: 8 mg/kg per 2-h period; >=70 kg: 600 mg (8 cartridges) per 2-h period
Dental local anesthesia — 4% injection	Children <10 yr	Rarely >1/2 cartridge (40 mg) per procedure (single tooth)		Per standard pediatric formula (e.g., Clark's rule; ~6.6-8.8 mg/kg in a 5-yr-old)

Renal Undefined

Hepatic Use with caution in hepatic disease; severe hepatic disease increases risk of toxic plasma concentrations (no specific dose given)

Maximum doses are per two-hour period

Instructions

Aspirate prior to injection to reduce intravascular injection risk
Use lowest dose giving effective anesthesia; observe maximum dose per any 2-hour period
Reduce doses in debilitated, elderly, acutely ill patients and children
Plain solution suited to short maxillary procedures (<=15 min); discard unused cartridge portion

Available strengths

inj 40 mg/mL

Contraindications

Known history of hypersensitivity to amide-type local anesthetics
Congenital or idiopathic methemoglobinemia

Cautions

Methemoglobinemia — highest risk in G6PD deficiency, infants <6 months, cardiac/pulmonary compromise, and with other oxidizing agents; treat with methylene blue if severe
Systemic toxicity (CNS excitation/depression, cardiovascular depression) from excessive dose or intravascular injection — resuscitative equipment must be immediately available
Repeated doses accumulate; reduce dose in debilitated/elderly/acutely ill patients and children
Caution in hepatic disease, severe shock, heart block, impaired cardiovascular function
Head and neck injections may produce systemic-toxicity-like reactions — monitor circulation and respiration
Have malignant hyperthermia management protocol available

Adverse reactions

CNS: lightheadedness, nervousness, confusion, dizziness, drowsiness, tinnitus, blurred/double vision, tremors, convulsions, unconsciousness, respiratory depression/arrest
CV: bradycardia, hypotension, cardiovascular collapse, cardiac arrest
Methemoglobinemia (cyanosis; may be delayed hours)
Swelling and persistent paresthesia of lips/oral tissues (rarely >1 year)
Allergic: urticaria, edema, anaphylactoid reactions (extremely rare)

Pregnancy Category B — rat studies to 30x human dose showed no fetal harm; no adequate human studies; consider before use in early pregnancy.

Lactation Unknown whether excreted in human milk; exercise caution in nursing women.

Cost

Prilocaine (CITANEST)

Strength		#/mo	generic $/unit	CostPlus
40 mg/mL	inj	per unit		not offered

NADAC is a voluntary CMS survey of what retail community pharmacies pay for the drugs they stock. Prilocaine is administered under clinical supervision and dispensed outside retail pharmacies, so it rarely appears on surveyed invoices.

NO BOXED WARNINGS

Principal riskMethemoglobinemia from its metabolite

Classes and tags

Clinical profile

Therapeutic safety burden2 / 4

Overdose danger3 / 4

Weight-gain liability0 / 4

Sedation liability0 / 4

QT / Torsades0 / 4

Direct muscarinic antagonism0 / 4

Embryofetal risk1 / 4

Legacy pregnancy categoryB

Defining liabilityMethemoglobinemia and systemic local-anesthetic toxicity

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