What is the recommended dosage of benzonate for an adult or pediatric patient with a history of respiratory issues and possible impaired liver or kidney function?

Benzonatate Dosing Recommendations

Standard Adult Dosing

For adults and children over 10 years of age, the FDA-approved dosage is 100-200 mg three times daily as needed for cough, with a maximum daily dose of 600 mg in three divided doses. 1

• The usual starting dose is one 100 mg or 200 mg capsule three times daily 1
• Maximum single dose: 200 mg 1
• Maximum total daily dose: 600 mg 1
• Capsules must be swallowed whole and never broken, chewed, dissolved, cut, or crushed 1

Pediatric Considerations

Benzonatate is contraindicated in children under 10 years of age due to lack of established safety and efficacy, and documented fatal overdoses in this population. 1

• Safety and effectiveness have not been established in children below age 10 1
• Accidental ingestion has resulted in death in children under 10 years 1
• Death can occur within one hour of ingestion, with symptoms appearing within 15-20 minutes 1
• Keep completely out of reach of children due to rapid lethality 1

Patients with Respiratory Disease

Benzonatate can be used in patients with respiratory conditions, but requires careful patient education about proper administration to prevent local anesthetic effects. 1

• Unlike zanamivir (which is contraindicated in chronic respiratory disease), benzonatate has no specific contraindication for respiratory conditions 2
• The primary risk is improper administration (chewing/crushing) causing oral numbness and potential aspiration 1
• If numbness or tingling of tongue, mouth, throat, or face occurs, patients must refrain from eating or drinking until numbness resolves 1

Hepatic and Renal Impairment

No specific dose adjustments are provided in the FDA labeling for hepatic or renal impairment, as benzonatate pharmacokinetics in these populations have not been formally studied. 1

• The FDA label does not include dosage modifications for liver or kidney dysfunction 1
• Carcinogenicity, mutagenicity, and reproduction studies have not been conducted 1
• Use clinical judgment and monitor closely for adverse effects in patients with organ dysfunction 1

Critical Safety Warnings

Overdose can be rapidly fatal in both adults and children, with cardiac arrest occurring within 15-60 minutes of ingestion. 1, 3

• Overdose symptoms include restlessness, tremors, convulsions, coma, and cardiac arrest 1
• Death has been reported within one hour of ingestion 1
• Adults are also at risk for fatal overdose, not just children 1, 3
• One case report documented cardiac arrest in a 37-year-old who ingested less than 30 capsules (200 mg each) with alcohol 3
• Torsades de pointes has been reported in benzonatate overdose 4

Dosing Schedule Management

If a dose is missed, skip that dose entirely and resume at the next scheduled time—never double dose. 1

• Do not take 2 doses at one time 1
• Maintain at least 8-hour intervals between doses when taking three times daily 1

Pregnancy and Lactation

Benzonatate is Pregnancy Category C and should only be used if clearly needed, as safety data are lacking. 1

• Animal reproduction studies have not been conducted 1
• Unknown whether benzonatate is excreted in breast milk 1
• Exercise caution when administering to nursing women 1

Drug Interactions and Precautions

Benzonatate is chemically related to para-aminobenzoic acid anesthetics (procaine, tetracaine) and may cause adverse CNS effects in patients with prior sensitivity to these agents. 1

• Monitor for CNS effects possibly related to prior sensitivity to related local anesthetics 1
• Potential interaction with concomitant medications affecting CNS 1
• Mechanism involves voltage-gated sodium channel inhibition similar to local anesthetics 5