Thank you for your recent inquiry.
There is indeed a reasonably rich body of literature on the topic of lidocaine used to treat cough in general. Much of it comes from the Anesthesiology literature and refers to cough related to surgical proceedures such as bonchoscopies. There are, however, articles discussing the use of lidocaine for chronic cough as well. For your convenience, I have copied below some of the references, along with the abstracts where available.
The experience you had as a resident might be based on an article regarding the use of lidocaine in asthma. There were published reports of the effectiveness of lidocaine in asthma, and then later studies (an example of which is copied below) failed to confirm the effectiveness of lidocaine treatment in asthmatics.
Having said this, to answer your question specifically, I have used lidocaine in chronic coughers who have not responded to more "standard" treatment. We usually employ either 2% or 4% solution (neat) administered by compressor nebulizer. We give it as often as two to three times a day. My experience of course is purely anecdotal. We have not studied the use of lidocaine in cough systematically. However, based upon this experience, and once again I emphasize that this is an opinion based upon anecdote only, I feel that this treatment has been helpful to us over the years in many patients. The problem of course is that it is reasonably inconvenient, and some people find it uncomfortable due to anesthesia of the upper airway.
Nonetheless, since you asked for our experience, I would let you know that I think it can be an effective regimen.
Thank you again for your inquiry and we hope this response is helpful to you.
Respir Med. 2010 Jul;104(7):934-44. Epub 2010 Apr 10.
Pharmacological and non-pharmacological interventions for cough in adults with respiratory and non-respiratory diseases: A systematic review of the literature.
Molassiotis A, Bryan G, Caress A, Bailey C, Smith J.
School of Nursing, Midwifery & Social Work, University of Manchester, University Place, Manchester M13 9PL, UK. firstname.lastname@example.org
The management of cough in adults with respiratory and non-respiratory illnesses is suboptimal and based mostly on clinical opinions rather than evidence. A systematic review was carried out assessing all trials in adult patients with respiratory and non-respiratory diseases (excluding cancer) that had chronic cough as primary or secondary outcome. A total of 1177 trials were retrieved and 75 met the criteria for inclusion in the review. The vast majority were in patients with asthma and chronic obstructive pulmonary disease (COPD). Cough was the primary outcome in less than one-quarter of the studies. The measurement of cough was variable, mostly using unvalidated scales or being part of an overall 'symptoms' score. Positive results were overall seen with the use of corticosteroids, leukotriene receptor antagonists, mast cell stabilizers, ipratropium bromide, neltenexine, iodinised glycerol and lidocaine. Speech pathology training and symptom monitoring through SMS messages (accompanied by treatment adjustments) have also shown promise. Evidence for established anti-tussive agents such as codeine was scarce, with positive studies from the 1960s, whilst more recent studies showed no effect in patients with COPD. Many studies had conflicting results. It is imperative that the management of cough and its evidence base be improved, using higher quality research designs and with cough being the primary outcome of trials.
Anaesthesia. 2008 May;63(5):495-8.
The effect of lidocaine on remifentanil-induced cough.
Kim JY, Park KS, Kim JS, Park SY, Kim JW.
Department of Anaesthesiology and Pain Medicine, Ajou University College of Medicine, Suwon, Korea.
This study was performed to investigate the incidence of remifentanil-induced cough and evaluate the efficacy of lidocaine on its prevention. Five-hundred patients, aged 18-70 years, were randomly allocated into two groups to receive either lidocaine 0.5 mg x kg(-1) or 0.9% normal saline intravenously 1 min before remifentanil administration at a target effect-site concentration of 4 ng x ml(-1). Any episode of cough was classified as coughing and graded as mild (1-2), moderate (3-4) or severe (5 or more). We found that the overall incidence of cough was significantly higher in the saline group (69 patients; 27.6%) than that in the lidocaine group (38 patients; 15.2%) (p < 0.001). The results of logistic regression indicated that age and smoking were associated with remifentanil-induced cough. This study demonstrated that intravenously administered lidocaine 0.5 mg x kg(-1) effectively suppresses remifentanil-induced cough without possible systemic lidocaine toxicity
J Support Oncol. 2007 Jul-Aug;5(7):301-2.
Nebulized lidocaine for intractable cough near the end of life.
Lingerfelt BM, Swainey CW, Smith TJ, Coyne PJ.
PMID: 17708119 [PubMed - indexed for MEDLINE]
Am J Emerg Med. 2001 May;19(3):206-7.
Lidocaine inhalation for cough suppression.
Internal Medicine Unit, Al-Hasa Specialty Services Division, Saudi Aramco-Al-Hasa Health Center, Box 6030 Mubarraz 31311, Saudi Arabia. email@example.com
The purpose of this study was to observe the effectiveness of lidocaine in suppressing cough which is a logical extension of its established use in bronchoscopy. Nebulized lidocaine, preceded by standard nebulized albuterol inhalation driven by oxygen was given to suppress cough in a selected group of patients with intractable cough severe enough to disrupt daily life activities, especially sleep. Patients included those with asthma, reactive airways disease, and chronic obstructive pulmonary disease (COPD). In these selected patients, nebulized lidocaine was very effective in suppressing cough, and thus buying time for more definitive therapies to work. This observation merits further study and confirmation for the benefit of patients.(Am J Emerg Med 2001;19:206-207
Emerg Med J. 2005 Jun;22(6):429-32.
Comparison of lidocaine and bronchodilator inhalation treatments for cough suppression in patients with chronic obstructive pulmonary disease.
Chong CF, Chen CC, Ma HP, Wu YC, Chen YC, Wang TL.
Emergency Department, Shin-Kong Wu Ho-Su Memorial Hospital, No.95 Wen-Chang Road, Shi-Lin District, Taipei City, Taiwan. firstname.lastname@example.org
BACKGROUND: This study aimed to assess and compare the effectiveness of lidocaine and bronchodilator inhalation treatments for rapid cough suppression in patients with chronic obstructive pulmonary disease (COPD).
METHODS: Prospective comparison study carried out in a tertiary emergency department. Consecutive COPD patients presenting with intractable cough were randomly assigned to receive lidocaine or terbutaline inhalation treatments for cough suppression. Patients with dyspnoea, unstable vital signs, and pneumonia or neoplasm on chest x ray were excluded. A subjective, 10 point questionnaire based cough severity score was used for assessing the outcome.
RESULTS: The final study sample included 127 patients (mean (SD) age, 69.2 (12.1) years; 33.1% women) of whom 62 received nebulised lidocaine and 65 nebulised bronchodilator. The cough severity score was significantly reduced one hour after inhalation treatment with both lidocaine and bronchodilator, with no significant difference in efficacy. Common but mild side effects in the lidocaine group included oropharyngeal numbness and bitter taste, and, in the bronchodilator group, tremor and palpitation. Dyspnoea, dizziness, and nausea and vomiting were equally uncommon in both groups. None of these problems caused any of the patients to discontinue their treatments and no allergic reactions were reported.
CONCLUSIONS: Both lidocaine and bronchodilator inhalation treatments are equally effective for short term cough suppression in patients with COPD
Phil Lieberman, M.D.