Adult: Available preparation:
Each mL of solution for inj contains prilocaine 30 mg and felypressin 0.54 mcg
Dental infiltration and dental nerve block techniques: Usual dose: 1-5 mL. Max: 10 mL. Doses are administered slowly; aspirate the syringe after tissue penetration and before inj to avoid inadvertent intravascular inj. Dose is individualised based on the physical condition of the patient, anaesthesia technique, vascularity of the oral tissue, and the area of the oral cavity to be anaesthetised. Use the lowest effective dose. Elderly: Dosage reduction may be required. Child: Available preparation:
Each mL of solution for inj contains prilocaine 30 mg and felypressin 0.54 mcg
Dental infiltration and dental nerve block techniques: <10 years Usual dose: 1-2 mL (Max: 10 mL); ≥10 years Same as adult dose. Doses are administered slowly; aspirate the syringe after tissue penetration and before inj to avoid inadvertent intravascular inj. Dose is individualised based on the physical condition of the patient, anaesthesia technique, vascularity of the oral tissue, and the area of the oral cavity to be anaesthetised. Use the lowest effective dose.
Special Patient Group
Debilitated patients: Dosage reduction may be required.
Contraindications
Hypersensitivity to prilocaine and other anaesthetics of the amide-type, or felypressin. Congenital or idiopathic methaemoglobinaemia; inflammation or sepsis in the region of proposed inj.
Special Precautions
Patient with severe anaemia; CV disease (e.g. severe bradycardia, impaired cardiac conduction, severe or untreated hypertension, circulatory failure of any cause), impaired respiratory function, diabetes; history of seizure, genetic predisposition to malignant hyperthermia, G6PD deficiency. Avoid intravascular inj. Debilitated and acutely ill patients. Renal and hepatic impairment. Children and elderly. Pregnancy and lactation.
Adverse Reactions
Significant: CV effects particularly with excessive doses (e.g. cardiac vasoconstriction, increased blood pressure); methaemoglobinaemia, cyanosis; neurological reactions (e.g. numbness, paraesthesia, sensory disturbances); risk of oral trauma. Cardiac disorders: Bradycardia, cardiac insufficiency. Ear and labyrinth disorders: Tinnitus. Eye disorders: Blurred vision. Gastrointestinal disorders: Nausea, vomiting. Immune system disorders: Rarely, hypersensitivity reaction. Nervous system disorders: Dizziness, drowsiness, headache, tremor, seizure, loss of consciousness. Psychiatric disorders: Nervousness, disorientation. Vascular disorders: Hypotension. Potentially Fatal: Rarely, cardiac or respiratory arrest.
Patient Counseling Information
This drug may temporarily impair locomotion and coordination, if affected, do not drive or operate machinery. This medicine may also increase the risk of accidental trauma by the patient to the lips, tongue, cheek mucosa or soft palate; to avoid inadvertent injury, refrain from food ingestion until normal oral function and sensation return.
Overdosage
Symptoms: Nervousness, dizziness, blurred vision and tremors, followed by drowsiness, unconsciousness, convulsions and possibly respiratory arrest. CV reactions such as peripheral vasodilation, hypotension, myocardial depression, bradycardia and possibly cardiac arrest may also occur. Management: Ensure patent airway. If ventilation is inadequate, provide assisted or controlled ventilation with oxygen. IV diazepam or thiopentone Na may be administered to control convulsions. Supportive treatment for circulatory depression such as administration of fluids and/or vasopressor (e.g. ephedrine) may be required. Initiate effective CV resuscitation if cardiac arrest occurs.
Drug Interactions
Prilocaine: Increased risk of methaemoglobinaemia with sulfonamides (e.g. sulfamethoxazole), antimalarials (e.g. chloroquine) and certain nitric compounds (e.g. nitric oxide, Na nitrite). Enhanced adverse effects with other local anaesthetics and agents structurally related to amide-type local anaesthetics. May increase the risk of cardiac toxic effects with antiarrhythmics (e.g. amiodarone).
Action
Description: Mechanism of Action: Prilocaine is an amide-type local anaesthetic. It stabilises the neuronal membrane by reversibly blocking the Na ion influx through the nerve membrane required for the initiation and conduction of nerve impulses.
Felypressin is a synthetic vasopressin analogue. It reduces the absorption rate of prilocaine from the site of inj. Onset: 2 minutes (infiltration); 4 minutes (block). Duration: Infiltration: 40 minutes (pulp); 2.5 hours (soft tissue). Block: 90 minutes (pulp); 3.5 hours (soft tissue). Pharmacokinetics: Distribution: Prilocaine: Crosses the placenta and blood-brain barrier; enters breast milk. Volume of distribution: 190-260 L. Plasma protein binding: 40-55%, mainly to α1-acid glycoprotein. Metabolism: Prilocaine: Rapidly metabolised mainly in the liver and to a lesser extent in the kidneys by amidases to form o-toluidine and N-propylalanine. Excretion: Prilocaine: Via urine (<5% as unchanged drug). Elimination half-life: 1.6 hours.
Chemical Structure
Prilocaine Source: National Center for Biotechnology Information. PubChem Database. Prilocaine, CID=4906, https://pubchem.ncbi.nlm.nih.gov/compound/Prilocaine (accessed on Jan. 23, 2020)
Felypressin Source: National Center for Biotechnology Information. PubChem Compound Summary for CID 14257662, Felypressin. https://pubchem.ncbi.nlm.nih.gov/compound/Felypressin. Accessed Nov. 25, 2021.