prilocaine (Rx)

Frequency Not Defined

CNS depression manifested by drowsiness, unconsciousness, respiratory arrest, nausea, vomiting, chills, miosis, tinnitus; myocardial depression, bradycardia, cardiac arrhythmias, hypotension, cardiovascular collapse, cardiac arrest; palpitation, headache, tremors, tachycardia, anginal pain, hypertension (epinephrine-containing solutions)

Anxiety

Apprehension

Restlessness

Nervousness

Disorientation

Confusion

Dizziness

Blurred vision

Tremors

Twitching

Shivering

Seizures

Edema

Status asthmaticus

Anaphylactoid reactions (sometimes fatal)

Contraindications

Hypersensitivity to prilocaine, amide-type local anesthetics, sulfites, parabens

Idiopathic or congenital methemoglobinemia

Cautions

Administration of >600 mg to adults causes non-acute 15% methemoglobinemia via formation of o-toluidine metabolite

Use preservative-free preparations for spinal or epidural anesthesia

DO NOT use solutions with epinephrine in distal areas of body (e.g. digit, nose, ear, etc)

History of malignant hyperthermia

Respiratory arrest reported with local anesthetics

Seizures reported with systemic toxicity

Addition of vasoconstrictor, epinephrine, will promote local hemostasis, decrease systemic absorption, and increase duration of action

Methemoglobinemia

• Use of local anesthetics may cause methemoglobinemia, a serious condition that must be treated promptly; patients with glucose-6-phosphate dehydrogenase deficiency, congenital or idiopathic methemoglobinemia, cardiac or pulmonary compromise, infants under 6 months of age, and concurrent exposure to oxidizing agents or their metabolites are more susceptible to developing clinical manifestations of the condition
• Advise patients or caregivers to seek immediate medical attention if patient experiences the following signs or symptoms: pale, gray, or blue colored skin (cyanosis); headache; rapid heart rate; shortness of breath; lightheadedness; or fatigue; discontinue Bicillin C-R and any other oxidizing agents; depending on severity of signs and symptoms, patients may respond to supportive care, including oxygen therapy and hydration; a more severe clinical presentation may require treatment with methylene blue, exchange transfusion, or hyperbaric oxygen

Pregnancy Category: C

Lactation: not known if excreted in breast milk

Pregnancy Categories

A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

NA: Information not available.

Mechanism of Action

Local anesthetics prevent generation/conduction of nerve impulses by reducing sodium permeability and increasing action potential threshold

Absorption

Duration: the greater the degree of vasodilation produced by the local anesthetic, the faster the rate of absorption & shorter the duration of action (bupivacaine has a long duration of action)

Distribution

Protein bound: 55%

Vd: 0.6-4.4 L/kg

Onset: 2 min (infiltration); 3 min (inferior alveolar nerve block)

Metabolism

Metabolism: Liver and kidney

Metabolites: Ester- & amide-type local anesthetics

Elimination

Excretion: Urine (principally)

Half-life: 10-150 min