Usage
- Benzonatate is prescribed for the symptomatic relief of cough. It is effective for coughs caused by colds, flu, or other respiratory infections. It’s important to note that it’s not intended for chronic coughs associated with smoking, asthma, or emphysema, or coughs producing excessive mucus.
- Pharmacological classification: Antitussive (cough suppressant).
- Mechanism of action: Benzonatate works peripherally by anesthetizing the stretch receptors located in the respiratory passages, lungs, and pleura. This dampens their activity and reduces the cough reflex at its source. Unlike centrally acting cough suppressants (e.g., opioids), benzonatate does not depress respiration.
Alternate Names
- No widely used alternate generic names exist.
- Brand names: Tessalon Perles, Zonatuss.
How It Works
- Pharmacodynamics: Benzonatate reduces the cough reflex by anesthetizing the stretch receptors in the respiratory tract. This local anesthetic action minimizes the transmission of cough impulses to the central nervous system.
- Pharmacokinetics:
- Absorption: Well-absorbed from the gastrointestinal tract.
- Metabolism: The exact metabolic pathway of benzonatate is not fully elucidated.
- Elimination: Primarily eliminated via hepatic metabolism, with metabolites excreted in urine.
- Mode of action: Benzonatate structurally resembles local anesthetics like tetracaine. It acts by binding to and inhibiting voltage-gated sodium channels on sensory nerve endings of the cough receptors. This blockade of sodium channels reduces the excitability of these nerves, decreasing the frequency and intensity of cough impulses.
- Receptor binding/enzyme inhibition/neurotransmitter modulation: Benzonatate primarily exerts its effects by inhibiting sodium channels. Other receptor interactions, enzymatic actions, or neurotransmitter modulations are not yet extensively studied.
- Elimination pathways: Predominantly hepatic metabolism followed by renal excretion of metabolites.
Dosage
Standard Dosage
Adults:
- 100 mg to 200 mg orally three times a day, as needed for cough.
- Maximum single dose: 200 mg.
- Maximum daily dose: 600 mg.
Children:
- Children under 10 years: Use is not recommended due to the risk of accidental ingestion and potentially fatal overdose.
- Children over 10 years: Same as adult dosage (100 mg to 200 mg orally three times a day as needed for cough, up to a maximum of 600 mg/day).
Special Cases:
- Elderly Patients: No specific dose adjustments are recommended, but caution is advised, starting at the lower end of the dosing range.
- Patients with Renal Impairment: No specific dose adjustments are recommended. However, caution is needed due to the limited data on the exact pathway of metabolism and elimination in this population.
- Patients with Hepatic Dysfunction: No specific dose adjustments are recommended. Close monitoring for adverse effects is advised.
- Patients with Comorbid Conditions: Use with caution in patients with other medical conditions, especially those affecting respiratory function.
Clinical Use Cases
- Intubation/Surgical Procedures/Mechanical Ventilation/ICU Use/Emergency Situations: Benzonatate is not typically used in these clinical settings. Other medications are preferred for managing airway reflexes and secretions during these situations.
Dosage Adjustments
- Currently, no specific dosage adjustments are universally established for renal/hepatic dysfunction, metabolic disorders, or genetic polymorphisms. Clinical judgment and patient-specific factors should be considered.
Side Effects
Common Side Effects
- Dizziness
- Drowsiness
- Headache
- Constipation
- Nausea
- Upset stomach
- Skin rash or itching
- Nasal congestion
Rare but Serious Side Effects
- Confusion
- Hallucinations
- Numbness or tingling in the mouth, throat, or face
- Chest numbness
- Chills
- Burning in the eyes
- Difficulty breathing
- Difficulty speaking
- Choking sensation
- Allergic reactions (bronchospasm, laryngospasm, cardiovascular collapse)
Long-Term Effects
- No specific long-term adverse effects have been identified.
Adverse Drug Reactions (ADR)
- Severe hypersensitivity reactions (bronchospasm, laryngospasm, cardiovascular collapse).
- Mental confusion and visual hallucinations (rare, more common when combined with other drugs).
Contraindications
- Hypersensitivity to benzonatate or related compounds (e.g., tetracaine, procaine).
- Children under 10 years of age.
Drug Interactions
- Other drugs that cause drowsiness (e.g., opioids, alcohol, benzodiazepines, muscle relaxants, antihistamines, certain antidepressants). Concurrent use can increase the risk of excessive sedation.
Pregnancy and Breastfeeding
- Pregnancy Safety Category: C (animal studies show adverse effects, human studies inadequate). Use only if clearly needed and the potential benefits outweigh the risks.
- Breastfeeding: Excretion in breast milk is unknown. Caution is advised. Consider the potential risks to the infant.
Drug Profile Summary
- Mechanism of Action: Peripherally acting antitussive; anesthetizes stretch receptors in the respiratory tract.
- Side Effects: Drowsiness, dizziness, headache, constipation, nausea, skin rash, nasal congestion; rarely confusion, hallucinations, numbness, choking sensation, allergic reactions.
- Contraindications: Hypersensitivity, children under 10 years.
- Drug Interactions: Other medications that cause drowsiness (additive CNS depression).
- Pregnancy & Breastfeeding: Category C; caution advised during breastfeeding.
- Dosage: Adults and children over 10 years: 100-200 mg three times daily, up to 600 mg/day.
- Monitoring Parameters: Respiratory rate, mental status, signs of allergic reactions.
Popular Combinations
- Not typically used in combination therapies. Monotherapy is preferred.
Precautions
- General Precautions: Swallow capsules whole; do not chew, suck, crush, or break. Ingestion of capsule contents can lead to oropharyngeal anesthesia and choking.
- Specific Populations:
- Pregnant Women: Use with caution, only if clearly needed.
- Breastfeeding Mothers: Caution advised due to the lack of safety data.
- Children & Elderly: Use not recommended in children under 10; caution in elderly.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Benzonatate?
A: Adults and children over 10 years: 100-200 mg orally three times a day as needed for cough, up to a maximum of 600 mg/day. Children under 10 years: Use is not recommended.
Q2: How does Benzonatate work?
A: It anesthetizes stretch receptors in the airways, reducing the cough reflex.
Q3: What are the common side effects?
A: Dizziness, drowsiness, headache, constipation, nausea, skin rash, and nasal congestion.
Q4: Can Benzonatate be used in children?
A: No, it is not recommended for children under 10 due to the risk of fatal overdose.
Q5: Is Benzonatate safe during pregnancy?
A: Pregnancy Category C; use with caution only if clearly needed.
Q6: Can I take Benzonatate with other cough medications?
A: Avoid combining with other cough suppressants, especially those causing drowsiness (e.g., dextromethorphan, codeine).
Q7: What should I do if I miss a dose?
A: Skip the missed dose and take the next dose at the regular time. Do not double the dose.
Q8: Can Benzonatate be chewed or sucked?
A: No, capsules must be swallowed whole. Chewing or sucking can release medication in the mouth, leading to oropharyngeal anesthesia and choking.
Q9: What are the signs of a Benzonatate overdose?
A: Restlessness, tremors, convulsions, coma, cardiac arrest. Seek immediate medical attention if overdose is suspected.
