PRILOCAINE HYDROCHLORIDE- prilocaine hydrochloride injection, solution
Septodont Inc.
For Local Anesthesia in Dentistry
Rx only
DESCRIPTION
Prilocaine Hydrochloride Injection, USP, 4% is a sterile, non pyrogenic isotonic solution that contains a local anesthetic agent and is administered parenterally by injection. See INDICATIONS AND USAGE for specific uses. The quantitative composition is shown in Table 1.
Prilocaine Hydrochloride Injection, USP, 4% contains prilocaine HCl, which is chemically designated as propanamide, N-(2-methyl-phenyl) -2- (propylamino)-, monohydrochloride.
Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration.
The specific quantitative composition is shown in Table 1.
TABLE 1. COMPOSITION
Product Identification Formula (mg/mL)
Prilocaine HCl pH
Prilocaine Hydrochloride Injection, USP, 4% 40.0 6.0 to 7.0
Note: Sodium hydroxide or hydrochloric acid may be used to adjust the pH of Prilocaine Hydrochloride Injection, USP, 4%.
CLINICAL PHARMACOLOGY
Mechanism of Action
Prilocaine stabilizes the neuronal membrane by inhibiting the ionic fluxes required for the initiation and conduction of impulses, thereby effecting local anesthetic action.
Onset and Duration of Action
When used for infiltration injection in dental patients, the time of onset of anesthesia averages less than 2 minutes with an average duration of soft tissue anesthesia of approximately 2 hours.
Based on electrical stimulation studies, Prilocaine Hydrochloride Injection, USP, 4% provides a duration of pulpal anesthesia of approximately 10 minutes in maxillary infiltration injections. In clinical studies, this has been found to provide complete anesthesia for procedures lasting an average of 20 minutes.
When used for inferior alveolar nerve block, the time of onset of Prilocaine Hydrochloride Injection, USP, 4% averages less than three minutes with an average duration of soft tissue anesthesia of approximately 21 /2 hours.
Hemodynamics
Excessive blood levels may cause changes in cardiac output, total peripheral resistance, and mean arterial pressure. These changes may be attributable to a direct depressant effect of the local anesthetic agent on various components of the cardiovascular system.
Pharmacokinetics and Metabolism
Information derived from diverse formulations, concentrations and usages reveals that prilocaine is completely absorbed following parenteral administration, its rate of absorption depending, for example, upon such factors as the site of administration and the presence or absence of a vasoconstrictor agent. Prilocaine is metabolized in both the liver and the kidney and excreted via the kidney. It is not metabolized by plasma esterases. Hydrolysis of prilocaine by amidases yields ortho-toluidine and N-proylalanine. Both of these compounds may undergo ring hydroxylation.
O-toluidine has been found to produce methemoglobin, both in vitro and in vivo (see ADVERSE REACTIONS).
Because prilocaine is metabolized in both the liver and kidneys, hepatic and renal dysfunction may alter prilocaine kinetics.
As with other local anesthetic agents, the plasma binding of prilocaine may be dependent on drug concentration. At 0.5 to 1.0 mg/mL it is 55% protein bound.
Prilocaine crosses the blood-brain and placental barriers, presumably by passive diffusion.
Factors such as acidosis and the use of CNS stimulants and depressants affect the CNS levels of prilocaine required to produce overt systemic effects. In the rhesus monkey, arterial blood levels of 20 mg/mL have been shown to be the threshold for convulsive activity.
INDICATIONS AND USAGE
Prilocaine Hydrochloride Injection, USP, 4% is indicated for the production of local anesthesia in dentistry by nerve block or infiltration techniques. Only accepted procedures for these techniques as described in standard textbooks are recommended.
