Dyclonine - Drug Monograph

Introduction

Dyclonine hydrochloride is a local anesthetic agent primarily used for topical anesthesia of mucous membranes. First introduced in the 1950s, it belongs to the ketone class of local anesthetics rather than the more common ester or amide types. Dyclonine is characterized by its rapid onset of action and relatively short duration of effect, making it particularly useful for procedures requiring brief anesthesia of oropharyngeal surfaces.

Mechanism of Action

Dyclonine exerts its local anesthetic effect by reversibly blocking voltage-gated sodium channels in neuronal membranes. This inhibition prevents the generation and propagation of action potentials along nerve fibers, thereby producing loss of sensation in the affected area. Unlike ester-type anesthetics, dyclonine is not metabolized to para-aminobenzoic acid (PABA), reducing the potential for allergic reactions associated with ester local anesthetics.

Indications

• Topical anesthesia of the oral pharyngeal mucosa for diagnostic procedures and instrumentation
• Relief of pain associated with minor oral mucosal inflammation
• Anesthesia prior to endoscopic procedures involving the upper gastrointestinal tract
• Temporary relief of pain from mouth ulcers, canker sores, and denture irritation

Dosage and Administration

• Oral use: Swish 5-10 mL for 30 seconds and expectorate
• Maximum recommended dose: 200 mg (40 mL of 0.5% solution) per procedure

• Pediatric: Safety and effectiveness not established for children under 12 years
• Geriatric: Use with caution due to potential increased sensitivity
• Hepatic impairment: No specific dosage adjustment recommended
• Renal impairment: Use with caution in severe renal impairment

Pharmacokinetics

Contraindications

• Known hypersensitivity to dyclonine or any component of the formulation
• Application to infected or traumatized mucous membranes where rapid absorption may occur
• Patients with severe hepatic impairment
• History of methemoglobinemia

Warnings and Precautions

• Risk of systemic toxicity if applied to large areas or damaged mucosa
• Potential for methemoglobinemia, especially with excessive doses
• Use with caution in patients with cardiac disease due to potential cardiovascular effects
• Avoid contact with eyes
• Not for ophthalmic use
• Use cautiously in patients with pre-existing respiratory conditions

Drug Interactions

• May potentiate effects of other local anesthetics
• MAO inhibitors may enhance sympathomimetic effects
• Beta-blockers may increase risk of bradycardia
• CYP450 inhibitors may decrease metabolism of dyclonine

Adverse Effects

• Transient stinging or burning at application site
• Mild erythema
• Altered taste perception
• Numbness of tongue and oral tissues

• Systemic toxicity: dizziness, tinnitus, blurred vision, tremors
• Cardiovascular: bradycardia, hypotension, arrhythmias
• CNS effects: seizures, respiratory depression
• Methemoglobinemia
• Allergic reactions including anaphylaxis

Monitoring Parameters

• Vital signs during and after procedure
• Signs of systemic toxicity
• Oxygen saturation if large areas treated
• Mental status changes
• Mucosal integrity at application site
• Methemoglobin levels if symptoms suggest methemoglobinemia

Patient Education

• Use only as directed by healthcare provider
• Do not swallow medication unless specifically instructed
• Avoid eating or drinking for at least 1 hour after application to prevent accidental biting of anesthetized areas
• Report any signs of allergic reaction: rash, itching, swelling
• Be aware of temporary numbness and avoid hot foods/liquids until sensation returns
• Do not drive or operate machinery until full sensation returns
• Store at room temperature, away from light and moisture

References

1. American Society of Health-System Pharmacists. AHFS Drug Information. Bethesda, MD: ASHP; 2023. 2. Becker DE, Reed KL. Local anesthetics: review of pharmacological considerations. Anesth Prog. 2012;59(2):90-102. 3. Food and Drug Administration. Dyclonine hydrochloride prescribing information. 2022. 4. Covino BG. Pharmacology of local anaesthetic agents. Br J Anaesth. 1986;58(7):701-716. 5. Tetzlaff JE. Clinical pharmacology of local anesthetics. Butterworth-Heinemann; 2000. 6. Rosenberg PH, Veering BT, Urmey WF. Maximum recommended doses of local anesthetics: a multifactorial concept. Reg Anesth Pain Med. 2004;29(6):564-575. 7. Thomson PD, Melmon KL. Clinical pharmacokinetics of local anesthetics. Clin Pharmacokinet. 1979;4(4):241-278.