Episode 987: Cough Suppressants

Contributor: Meghan Hurley, MD

Educational Pearls:

OTC Medications

• Dextromethorphan (DM)
  • Most common OTC cough suppressant
  • Minimal efficacy: Little evidence that it shortens the duration or severity of cough.
  • Potential side effects:
    • At recommended doses: Mild dizziness, drowsiness, GI symptoms
    • Higher doses: Decreased consciousness, dissociative effects
• Guaifenesin
  • Found in Mucinex and other severe cough/cold products
  • Thins secretions and loosens mucus in airways
  • No more effective than increasing oral fluid intake

Prescription Medications

• Codeine-containing products
  • Suppresses cough center in the medulla
  • Metabolized via CYP2D6 with significant differences in metabolism between individuals:
    • Low metabolizers experience little effect, high metabolizers have risk of increased toxicity
• Benzonatate (Tessalon Perles)
  • Topical anesthetic; inhibits pulmonary stretch receptors and reduces cough reflex.
  • Efficacy is mixed; no clear benefit over placebo.
  • Precautions: do not bite or chew; dangerous in children <2 years if chewed (risk of seizures, tremors, cardiac arrest)
• Inhaled/Nebulized Lidocaine
  • Used for chronic or refractory cough (patients with lung cancer, COPD)
  • Side effects: bitter taste, perioral numbness
  • Precautions: Keep patient NPO with continuous monitoring due to aspiration risk
  • Improvement usually within a few hours; duration of effect unclear

Children Over 1 Year

• Many children's OTC cough products are naturopathic and not FDA-approved.
• Other remedies:
  • Honey (only age >1 year; risk of botulism in infants), Vicks VapoRub on chest, thyme/honey/lemon tea mixture

Prolonged Cough

• Cough >2 weeks or post-tussive emesis → consider pertussis.
• Tdap immunity wanes over time; risk increases if Tdap is not received routinely.
• If pertussis is suspected, consider trial of a macrolide antibiotic.

References

1. Chong CF, Chen CC, Ma HP, Wu YC, Chen YC, Wang TL. Comparison of lidocaine and bronchodilator inhalation treatments for cough suppression in patients with chronic obstructive pulmonary disease. Emerg Med J. 2005 Jun;22(6):429-32. doi: 10.1136/emj.2004.015719. PMID: 15911951; PMCID: PMC1726806.
2. Havers FP, Moro PL, Hunter P, Hariri S, Bernstein H. Use of Tetanus Toxoid, Reduced Diphtheria Toxoid, and Acellular Pertussis Vaccines: Updated Recommendations of the
3. Lam SHF, Homme J, Avarello J, Heins A, Pauze D, Mace S, Dietrich A, Stoner M, Chumpitazi CE, Saidinejad M. Use of antitussive medications in acute cough in young children. J Am Coll Emerg Physicians Open. 2021 Jun 18;2(3):e12467. doi: 10.1002/emp2.12467. PMID: 34179887; PMCID: PMC8212563.
4. Malesker MA, Callahan-Lyon P, Ireland B, Irwin RS; CHEST Expert Cough Panel. Pharmacologic and Nonpharmacologic Treatment for Acute Cough Associated With the Common Cold: CHEST Expert Panel Report. Chest. 2017 Nov;152(5):1021-1037. doi: 10.1016/j.chest.2017.08.009. Epub 2017 Aug 22. PMID: 28837801; PMCID: PMC6026258.
5. Singu B, Verbeeck RK. Should Codeine Still be Considered a WHO Essential Medicine? J Pharm Pharm Sci. 2021;24:329-335. doi: 10.18433/jpps31639. PMID: 34192509.
   U.S. National Library of Medicine. Benzonatate capsule. DailyMed. Updated July 31, 2023. Accessed December 13, 2025. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=c21afd18-3b04-4f15-874b-25e0c768f801

Summarized by Ashley Lyons, OMS3 | Edited by Ashley Lyons and Jorge Chalit, OMS4

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