Previous studies of standard GERD therapy (PPIs) for patients with chronic cough were mostly based on small observational trials. Some of these studies disclosed that about 70% of individuals with chronic cough showed improvement with PPIs. However, recent randomized controlled trials reveal that PPIs for patients with persistent cough were not significantly beneficial.

Recent study of patients with chronic idiopathic cough and no heartburn, have shown no difference in outcomes between the group that received high-dose PPIs and the group that received placebo.

Studies have shown that syrups containing Bromhexine, Guaifenesin, Menthol and Terbutaline might also be beneficial in controlling chronic cough. 

Studies have shown that Bromhexine hydrochloride (BRH) is capable of inhibiting transmembrane protease serine 2 (TMPRSS2) and TMPRSS2-specific viral entry and is theoretically regarded to be effective against severe acute respiratory syndrome-coronavirus, hence beneficial against coronavirus disease 2019 (COVID-19), especially for patients with lung and hepatic injury. Large-scale clinical trial is needed to confirm further.¹

Guaifenesin, is another mucoactive drug, which acts by loosening mucus in the airways and making coughs more productive. It is used for relief of wet cough and chest congestion. Guaifenesin has a well-established and favorable safety and tolerability profile in adult and pediatric populations.²

Studies have shown that patients with cough due to different bronchitis have been benefited by the use of Guaifenesin. Fifty-four percent experienced significant reduction in cough frequency and severity. A total of 79% of patients on Guaifenesin experienced subjective improvement in tenaciousness of sputum compared to other treatments and placebo. Another study concluded that high-dose Guaifenesin might result in fewer infectious complications, reduced antibiotic use and improved quality of life.³

Menthol acts on the TRPM8 receptor on sensory nerves in the oral cavity and airway to give a cool sensation. Apart from providing a sensory impact to a cough medicine menthol may also have some specific antitussive properties as recognized by US Food and Drug Administration (FDA).⁴

Studies have proved that pre-inhalation of menthol prevented cough induced by inhaling citric acid. Itseems to have a capacity to reduce the sensitivity of an important airway defense mechanism that could be used for good.⁵

Terbutaline belongs to a class of drugs called beta-adrenergic agonist bronchodilators works by relaxing the muscles in the airways (bronchial tubes) in the lungs. This opens up the airways, which makes it easier to breathe. Studies have shown that both day and night cough scores (p < 0.001) and peak expiratory flow rates were significantly improved (p < 0.05) by the end of the first week of treatment with terbutaline.^6,7

Other treatment and preventions for chronic cough caused by acid reflux include lifestyle and dietary changes.

Maintaining a healthy body mass index (BMI), wearing loose clothing, eating slowly and avoiding overeating reduce some of the pressure on the stomach, lessening the amount of stomach acid forced up the food pipe. Smoking enhances the risk of developing GERD, so quitting smoking is best. Waiting for around 3 hours before lying down after meals, elevating the head of the bed may also help to reduce GERD and related cough.

Dietary changes such as avoiding certain foods and drinks that trigger acid reflux are helpful in reducing GERD and related cough. Alcohol, spicy food, high-fat foods, fried foods, caffeine; chocolate, citrus foods must be restricted.

Thus, keeping a check on the food habits, following healthy lifestyle and eating habits, taking medications even prescribed can lead to a stress free and healthy life.

Source:

1. Li T, Sun L, Zhang W, et al. Bromhexine hydrochloride tablets for the treatment of moderate COVID-19: an open-label randomized controlled pilot study. Clin Transl Sci. 2020;13(6):1096-102.
2. Albrecht HH, Dicpinigaitis PV, Guenin EP. Role of guaifenesin in the management of chronic bronchitis and upper respiratory tract infections. Multidiscip Respir Med. 2017;12:31.
3. Ohar JA, Donohue JF, Spangenthal S. The role of guaifenesin in the management of chronic mucus hypersecretion associated with stable chronic bronchitis: a comprehensive review. Chronic Obstr Pulm Dis. 2019;6(4):341-9.
4. Eccles R. The powerful placebo effect in cough: relevance to treatment and clinical trials. Lung. 2020;198(1):13-21.
5. Millqvist E. TRPV1 and TRPM8 in treatment of chronic cough. Pharmaceuticals (Basel). 2016;9(3):45.
6. Terbutaline, Oral Tablet.  Available from: https://www.healthline.com/health/drugs/terbutaline-oral-tablet#dosage. Accessed May 6, 2022.
7. Ellul-Micallef R. Effect of terbutaline sulphate in chronic "allergic" cough. Br Med J (Clin Res Ed). 1983;287(6397):940-3.