Citanest

Generic Name: Prilocaine Hydrochloride
Class: Local Anesthetics
ATC Class: N01BB54
VA Class: CN204
Chemical Name: Propanamide, N-(2-methyl-phenyl)-2- (propylamino)- monohydrochloride
CAS Number: 1786-81-8

Introduction

Intermediate-acting local anesthetic (amide type).a b

Uses for Citanest

Dental Anesthesia

Infiltration or nerve block anesthesia in dental procedures.a

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Citanest Dosage and Administration

General

  • Determine dosage based on anesthetic procedure, depth of anesthesia, area to be anesthetized, vascularity of oral tissues, physical condition of the patient, and individual patient response.a c Use smallest dose required to produce the desired effect.a

Administration

Injection

Administer by infiltration or by nerve block.a

Consult specialized references for specific techniques and procedures of administration.a b

Aspirate prior to administration to guard against intravascular injection.c

For maxillary infiltration for short procedures that can be completed within 15 minutes (e.g., procedures involving maxillary anterior teeth), use prilocaine hydrochloride 4% solution without epinephrine.c For long procedures or those involving maxillary posterior teeth, use prilocaine hydrochloride 4% solution with epinephrine 1:200,000.c

For inferior alveolar block, may use prilocaine hydrochloride alone or in fixed combination with epinephrine; no practical clinical differences between these preparations.c

For chemical disinfection of the cartridge unit, use isopropyl (rubbing) alcohol (91%) or ethyl alcohol (70%).c Do not use brands that are not of USP grade, since these preparations may contain denaturants that may be injurious to rubber.c Because certain metallic ions (e.g., mercury, zinc, copper) have been associated with swelling and edema following local anesthesia, do not use chemical disinfectants containing or releasing these ions.c Do not autoclave because solutions of epinephrine and the closures employed in cartridges cannot withstand autoclaving temperatures and pressures.c

Dosage

Available as prilocaine hydrochloride and as fixed combination containing prilocaine hydrochloride and epinephrine bitartrate.c Dosage expressed in terms of prilocaine hydrochloride.c

Pediatric Patients

Dental Anesthesia
Infiltration, Nerve Block

Children <10 years of age: 40 mg (1 mL) of prilocaine hydrochloride 4% solution (with or without epinephrine) is adequate for a procedure involving 1 tooth, 2–3 teeth (maxillary infiltration), or teeth in an entire quadrant (mandibular block).a c

Adults

Dental Anesthesia
Infiltration, Nerve Block

Initially, 40–80 mg (1–2 mL) of prilocaine hydrochloride 4% solution (with or without epinephrine) usually provides adequate infiltration or major nerve block anesthesia for most routine procedures.a c (See Prescribing Limits under Dosage and Administration.)

Prescribing Limits

Pediatric Patients

Dental Anesthesia
Infiltration, Nerve Block

For children <10 years of age with normal lean body mass and normal development, maximum dose is determined using standard pediatric drug formulas (e.g., Clark’s rule).a For example, dosage for a 5-year old child weighing 50 lbs should not exceed 150–200 mg (6.6–8.8 mg/kg or 3–4 mg/lb).c

Adults

Dental Anesthesia
Infiltration, Nerve Block

Patients weighing <70 kg: Maximum 8 mg/kg within a 2-hour period.c

Patients weighing ≥70 kg: Maximum 600 mg (15 mL) or 8 cartridges per injection and within a 2-hour period.c

Special Populations

Hepatic Impairment

Reduce dosage in patients with hepatic disease.b

Geriatric Patients

Reduce dosage based on age and physical status.b c

Other Populations

Reduce dosage in debilitated or acutely ill patients and in patients with arteriosclerosis or occlusive arterial disease.b c

Cautions for Citanest

Contraindications

  • Congenital or idiopathic methemoglobinemia.a

  • Known hypersensitivity to prilocaine or other local anesthetics of the amide type.a b

Warnings/Precautions

Warnings

Experience of Supervising Clinician

Should be used only by clinicians who are sufficiently knowledgeable in the diagnosis and management of dose-related toxicity and other acute emergencies that might arise.c Oxygen, resuscitative equipment, and drugs must be available for immediate use.a b c Delay in proper management of dose-related toxicity may result in acidosis, cardiac arrest, and, possibly, death.b

Accidental Intravascular Injection

Accidental intravascular injection may result in seizures, CNS or cardiorespiratory depression, coma, and/or respiratory arrest.b (See CNS Effects and also Cardiovascular Effects, under Cautions.)

Aspirate prior to administration to guard against intravascular injection.b c

Methemoglobinemia

Risk of methemoglobinemia.a c Increased risk in adults receiving dosages ≥600 mg,a very young patients, patients with congenital or idiopathic methemoglobinemia, patients with glucose-6-phosphate deficiencies, or patients receiving drugs associated with methemoglobinemia (e.g., sulfonamides, acetaminophen, benzocaine, chloroquine, dapsone, naphthalene, nitrates and nitrites, nitrofurantoin, nitroglycerin, nitroprusside, aminosalicylic acid, phenobarbital, phenytoin, primaquine, quinine).c (See Specific Drugs and Laboratory Tests under Interactions.)

Methemoglobinemia generally is dose related but may occur at any dose in susceptible individuals.c Methemoglobin concentrations <20% generally do not produce any clinical symptoms; however, if cyanosis occurs within 2–4 hours after injection, evaluate general health status of patient.c Other manifestations of methemoglobinemia may include tachycardia, fatigue, headache, lightheadedness, and dizziness.a

If hypoxia occurs, and recommended dosage has notbeen exceeded, treat with oxygen (because symptoms of hypoxia probably related to improper ventilation).a If hypoxia persists, administer methylene blue 1% solution (1–2 mg/kg by IV infusion over 5 minutes) to correct methemoglobinemia.a

In patients with anemia or cardiac failure in whom oxygen is limited, consider the disadvantage of further hypoxia secondary to methemoglobinemia.a

Epinephrine Administration

Some prilocaine hydrochloride preparations contain epinephrine, which may cause ischemic injury or necrosis.c Consider usual precautions associated with epinephrine administration.c (See Cardiovascular Effects under Cautions.)

Sensitivity Reactions

Hypersensitivity Reactions and Cross-sensitivity

Allergic reactions are rare.b c

Possible cutaneous lesions, urticaria, edema, or anaphylactoid reactions.c

No cross-sensitivity reported in patients allergic to p-aminobenzoic acid derivatives (e.g., benzocaine, procaine, tetracaine).c Cross-sensitivity between amide-type local anesthetics reported.b

Sulfite Sensitivity

Some prilocaine formulations contain sodium metabisulfite, which may cause allergic-type reactions (including anaphylaxis and life-threatening or less severe asthmatic episodes) in certain susceptible individuals.a b

General Precautions

CNS Effects

Toxic plasma concentrations of local anesthetics (resulting from systemic absorption) associated with adverse CNS effects (e.g., restlessness, anxiety, tinnitus, dizziness, blurred vision, tremors, depression, drowsiness, lightheadedness, nervousness, apprehension, euphoria, confusion, double vision, vomiting, sensations of heat/cold/numbness, twitching, seizures, unconsciousness, respiratory depression and arrest).c

Carefully monitor level of consciousness after each local anesthetic injection.c

Cardiovascular Effects

Toxic plasma concentrations of local anesthetics (resulting from systemic absorption) associated with adverse cardiovascular effects (e.g., bradycardia, hypotension, cardiovascular collapse [which may lead to cardiac arrest]).c

Carefully monitor cardiovascular and respiratory vital signs after each local anesthetic injection.c

Failure to recognize early manifestations of depressed cardiovascular function (e.g., sweating, feeling of faintness, changes in pulse or sensorium) may result in progressive cerebral hypoxia and seizure or serious cardiovascular catastrophe.c To manage cardiovascular depression, place patient in recumbent position and ventilate with oxygen.c May require administration of IV fluids and/or a vasopressor (e.g., ephedrine) depending on clinical presentation.c

Use with caution in patients with impaired cardiovascular function, severe shock, or heart block.c

Some prilocaine hydrochloride preparations contain epinephrine; risk of exaggerated vasoconstrictor response in patients with peripheral vascular disease or hypertensive vascular disease.c Use with caution in areas of the body supplied by end arteries or having otherwise compromised blood supply.c

Familial Malignant Hyperthermia

Many drugs used during the conduct of anesthesia may trigger familial malignant hyperthermia; not known whether amide-type local anesthetics may trigger this reaction.c However, standard protocol for management should be available.c Early unexplained signs of tachycardia, tachypnea, labile BP, and metabolic acidosis may precede temperature elevation.c If familial malignant hyperthermia is confirmed, discontinue triggering agent and initiate appropriate therapy (e.g., oxygen, dantrolene) and other supportive measures.c

Risks Associated with Administration

Small doses of local anesthetics injected into the head and neck area (including retrobulbar, dental, and stellate ganglion blocks) may produce adverse reactions similar to systemic toxicity seen with unintentional intravascular injections of larger doses.c Confusion, seizures, respiratory depression and/or respiratory arrest, and cardiovascular stimulation or depression reported.c Monitor circulation and respiration in patients receiving these blocks.c

Serious Adverse Effects associated with Local Anesthetics

Risk of serious adverse effects (e.g., seizures, coma, irregular heart beat, respiratory depression) with use of topical local anesthetics; generally reported following application of extemporaneously prepared topical preparations containing high concentrations of anesthetics.k

Potential for life-threatening adverse effects (e.g., irregular heart beat, seizures, breathing difficulties, coma, death) when topical local anesthetics are applied to a large area of skin, when the area of application is covered with an occlusive dressing, if a large amount of topical anesthetic is applied, if the anesthetic is applied to irritated or broken skin, or if the skin temperature increases (from exercise or use of a heating pad).101 102

Lidocaine 4% gel has been investigated to reduce discomfort during mammography.101 103 Whether such use could result in serious reactions has not been determined.101 103 Patients should speak with their clinician if they are considering using a topical anesthetic before obtaining a mammogram.101

When a topical anesthetic is needed for a procedure, use of an FDA-approved preparation has been recommended.k Use a preparation containing the lowest concentration of anesthetic likely to be effective; apply a small amount of the preparation to the affected area for the shortest period necessary for the desired effect,k and do not apply to broken or irritated skin.101

Use of Fixed Combination

When used in fixed combination with other agents, consider the cautions, precautions, and contraindications associated with the concomitant agents.

Specific Populations

Pregnancy

Category B.c

Lactation

Not known whether prilocaine is distributed into milk.a Caution if used in nursing women.c

Pediatric Use

Reduce dosage based on age, body weight, and physical condition.c (See Pediatric Patients under Dosage and Administration.)

Geriatric Use

Reduce dosage based on age and physical status.b c

Hepatic Impairment

Possible increased risk of toxicity, particularly in patients with severe hepatic impairment.c Use with caution.c Dosage adjustments recommended.b

Common Adverse Effects

Adverse CNS and cardiovascular effects,c swelling and persistent paresthesia of the lips and oral tissues, persistent neurologic deficit.c (See CNS Effects and also Cardiovascular Effects, under Cautions.)

Interactions for Citanest

Consider usual drug interactions associated with epinephrine administration.c

Specific Drugs and Laboratory Tests

Drug

Interaction

Comments

Acetaminophen

Possible increased risk of methemoglobinemiac

Aminosalicylic acid

Possible increased risk of methemoglobinemiac

Anesthetics, general

Possible serious cardiac arrhythmias due to epinephrine componentc

Use concomitantly with cautionc

Anticonvulsants (phenobarbital, phenytoin)

Possible increased risk of methemoglobinemiac

Antidepressants, tricyclics

Possible severe, prolonged hypotension or hypertension due to epinephrine componentc

Avoid concomitant use; if must be used concomitantly, careful monitoring is requiredc

Antimalarials (chloroquine, primaquine, quinine)

Possible increased risk of methemoglobinemiac

Benzocaine

Possible increased risk of methemoglobinemiac

Dapsone

Possible increased risk of methemoglobinemiac

Ergot alkaloid oxytocics (ergonovine, methylergonovine)

Possible severe, persistent hypertension or cerebrovascular accidentsc

MAO inhibitors

Possible severe, prolonged hypotension or hypertension due to epinephrine componentc

Avoid concomitant use; if must be used concomitantly, careful monitoring is requiredc

Nitrates and nitrites (nitroglycerin)

Possible increased risk of methemoglobinemiac

Nitrofurantoin

Possible increased risk of methemoglobinemiac

Nitroprusside

Possible increased risk of methemoglobinemiac

Phenothiazines

Possible severe, prolonged hypotension or hypertension due to epinephrine componentc

Avoid concomitant use; if must be used concomitantly, careful monitoring is requiredc

Sulfonamides

Possible increased risk of methemoglobinemiac

Test for CPK

Possible increased CPK concentrations following IM injection of prilocainec

Accuracy as diagnostic test for AMI compromised if used without isoenzyme separationc

Citanest Pharmacokinetics

Absorption

Bioavailability

Rate of systemic absorption dependent upon factors such as administration site and presence or absence of epinephrine in formulation.c

Onset

Following infiltration with 4% prilocaine solution (with or without epinephrine), onset occurs in <2 minutes.a c

Following inferior alveolar nerve block with 4% prilocaine solution (with or without epinephrine), onset occurs in <3 minutes.a c

Duration

Following maxillary infiltration with 4% prilocaine solution without epinephrine, pulp anesthesia persists for 10–15 minutes,a c which provides complete anesthesia for procedures lasting an average of 20 minutes.c Average duration of soft tissue anesthesia is approximately 2 or 2.25 hours following infiltration with 4% prilocaine solution without or with epinephrine, respectively.c

Following inferior alveolar nerve block, average duration is approximately 2.5 or 3 hours with 4% prilocaine solution without or with epinephrine, respectively.a c

When used for infiltration or nerve block without epinephrine, duration of anesthesia is longer than that of an equal dose of lidocaine.a When epinephrine is added to both drugs, duration of anesthesia of lidocaine is lengthened to a greater extent than that of prilocaine.a

Distribution

Extent

Local anesthetics are distributed to all body tissues.b

Crosses blood-brain and placental barriers.a

Not known if distributed into milk.a

Plasma Protein Binding

At concentrations of 0.5–1 mg/mL, approximately 55% of drug is bound.c

Elimination

Metabolism

Systemically absorbed prilocaine is metabolized principally in the liver to o-toluidine and l-N-n-propylamine;a o-toluidine found to produce methemoglobin (see Methemoglobinemia under Cautions).c Some metabolism also may occur in the kidneys.a

Elimination Route

Excreted in urine as various metabolites; <1% excreted as unchanged drug.a

Special Populations

Hepatic and renal impairment may alter pharmacokinetics.c Possible toxic plasma concentrations in patients with severe hepatic disease.c

Stability

Storage

Parenteral

Injection

Room temperature (approximately 25°C).c If preparation contains epinephrine, protect from light.c Discard unused portion.c

Actions

  • Local anesthetics block the generation and conduction of nerve impulses by increasing the threshold for electrical excitability, slowing the propagation of the nerve impulse, and reducing the rate of rise in the action potential.b c

  • Produces less vasodilation than an equal dose of lidocaine hydrochloride.a

  • Some preparations formulated with epinephrine to decrease prilocaine’s rate and extent of systemic absorption and to prolong its duration of action.a b

  • Has intermediate duration of action.a b

Advice to Patients

  • Prior to administration, advise patients of the possibility of temporary loss of sensation and muscle function following infiltration or nerve block injections.c

  • Advise patients to avoid inadvertent trauma to the lips, tongue, cheek mucosae, or soft palate when these structures are anesthetized; postpone ingestion of food until normal function returns.c

  • Advise patient to consult dentist if anesthesia persists or if rash develops.c

  • Importance of informing clinicians of existing or contemplated concomitant therapy, including prescription and OTC drugs, as well as any concomitant illnesses (e.g., cardiovascular or liver disease).c

  • Importance of women informing their clinician if they are or plan to become pregnant or plan to breast-feed.c

  • Importance of informing patients of other important precautionary information. (See Cautions.)

Preparations

Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Prilocaine Hydrochloride

Routes

Dosage Forms

Strengths

Brand Names

Manufacturer

Parenteral

Injection

4%

Citanest Plain

Dentsply

Prilocaine Hydrochloride Combinations

Routes

Dosage Forms

Strengths

Brand Names

Manufacturer

Parenteral

Injection

4% with Epinephrine Bitartrate 1:200,000 (of epinephrine)

Citanest Forte

Dentsply

AHFS DI Essentials. © Copyright, 2004-2014, Selected Revisions July 1, 2009. American Society of Health-System Pharmacists, Inc., 7272 Wisconsin Avenue, Bethesda, Maryland 20814.

References

a. AHFS drug information 2004. McEvoy GK, ed. Prilocaine. Bethesda, MD: American Society of Health-System Pharmacists; 2007:3264-5.

b. AHFS drug information 2007. McEvoy GK, ed. Local Anesthetics, Parenteral, General Statement. Bethesda, MD: American Society of Health-Systems Pharmacists; 2007:3255-8.

c. Dentsply Pharmaceutical. Citanest Plain Dental (prilocaine HCl injection) 4% injection and Citanest Forte Dental (prilocaine and epinephrine injection) 4% Injection with epinephrine 1:200,000 prescribing information. York, PA; 2004 Feb.

k. Food and Drug Administration. FDA Public Health Advisory: Life-threatening side effects with use of skin products containing numbing ingredients for cosmetic procedures. 2007 Feb 6, updated 2007 Feb 9. From FDA website ().

101. Food and Drug Administration. FDA Public Health Advisory: Potential hazards of skin products containing numbing ingredients for relieving pain from mammography and other medical tests and conditions. 2009 Jan 16. From FDA website ().

102. Food and Drug Administration. Topical Anesthetics. MedWatch alert. Rockville, MD; 2009 Jan 16. From FDA website (

103. Lambertz CK, Johnson CJ, Montgomery PG et al. Premedication to reduce discomfort during screening mammography. Radiology. 2008; 248:765-72. [PubMed 18647845]

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