Safety of ambroxol in the treatment of airway diseases in adult patients

Ambroxol hydrochloride spray (Luo Runchang®) in the treatment of acute respiratory infectious diseases: a prospective, multicenter, open label, randomized controlled study

Purpose

Cough and sputum are the most common clinical symptoms of acute respiratory tract infection. Ambroxol is a mucolytic expectorant commonly used in clinical practice. This study aimed to evaluate the efficacy, safety, and compliance of ambroxol hydrochloride spray (Luo Runchang ®) for the treatment of acute respiratory tract diseases in children.

Methods

This was a multicenter, open-labeled, randomized controlled study. The experimental group received ambroxol hydrochloride oral sprays, and the control group received ambroxol hydrochloride oral solutions. The primary endpoint was the change in cough symptom scores from baseline. Secondary endpoints include changes in cough severity score, quality of life, adherence, and adverse events.

Results

A total of 154 subjects were randomized and included in the analysis. The mean change of total cough symptom score of the spray group at the end of treatment was -4.7 (1.54) compared to -4.2 (1.62) in the solution group (P = 0.0005). The mean change of cough severity score was -5.7 (2.09) in the spray group compared to -5.2(2.04) in the solution group (P = 0.012). Quality of life scores significantly improved in the spray group (P < 0.0001) compared to the oral solution group. Medication adherence markers were significantly better in the spray group (P < 0.0001). The incidence of adverse events in the experimental group (1.33%) was lower than that in the control group (6.33%), but the difference between the groups was not statistically significant.

Conclusion

Ambroxol hydrochloride spray significantly improved cough symptom score, cough severity score, and quality of life score compared to ambroxol hydrochloride oral solution.

Molecular mechanisms of the ambroxol action in Gaucher disease and GBA1 mutation-associated Parkinson disease

Glucocerebrosidase (GCase), encoded by the GBA1 gene, is one of the lysosomal enzymes responsible for hydrolyzing the glycosphingolipids. Deficiency in GCase activity (in patients with two defective alleles of GBA1) leads to glucosylceramide storage in lysosomes which in turn results in the development of the Gaucher diseases, a lysosomal storage disorder, while a heterozygous state may be correlated with the GBA1 mutation-associated Parkinson disease. One of the proposed forms of therapy for these two conditions is the use of pharmacological chaperones which work by facilitating the achievement of the correct conformation of abnormally folded enzymes. Several compounds with chaperone activities against GCase have already been tested, one of which turned out to be ambroxol. Studies conducted on the action of this compound have indeed indicated its effectiveness in increasing GCase levels and activity. However, some data have begun to question its activity as a chaperone against certain GCase variants. Then, a number of articles appeared pointing to other mechanisms of action of ambroxol, which may also contribute to the improvement of patients' condition. This paper summarizes the biological mechanisms of action of ambroxol in Gaucher disease and GBA1 mutation-associated Parkinson disease, focused on its activity as a chaperone, modulator of ERAD pathways, inducer of autophagy, and pain reliever in cellular and animal models as well as in patients. The effects of these activities on the reduction of disease markers and symptoms in patients are also discussed. Consideration of all the properties of ambroxol can help in the appropriate choice of therapy and the determination of the effective drug dose.

Exploring the efficacy and safety of Ambroxol in Gaucher disease: an overview of clinical studies

Gaucher disease (GD) is mainly caused by glucocerebrosidase (GCase) enzyme deficiency due to genetic variations in the GBA1 gene leading to the toxic accumulation of sphingolipids in various organs, which causes symptoms such as anemia, thrombocytopenia, hepatosplenomegaly, and neurological manifestations. GD is clinically classified into the non-neuronopathic type 1, and the acute and chronic neuronopathic forms, types 2 and 3, respectively. In addition to the current approved GD medications, the repurposing of Ambroxol (ABX) has emerged as a prospective enzyme enhancement therapy option showing its potential to enhance mutated GCase activity and reduce glucosylceramide accumulation in GD-affected tissues of different GBA1 genotypes. The variability in response to ABX varies across different variants, highlighting the diversity in patients' therapeutic outcomes. Its oral availability and safety profile make it an attractive option, particularly for patients with neurological manifestations. Clinical trials are essential to explore further ABX's potential as a therapeutic medication for GD to encourage pharmaceutical companies' investment in its development. This review highlights the potential of ABX as a pharmacological chaperone therapy for GD and stresses the importance of addressing response variability in clinical studies to improve the management of this rare and complex disorder.

Novel Drug Targets and Emerging Pharmacotherapies in Neuropathic Pain

Neuropathic pain is a debilitating condition characterized by abnormal signaling within the nervous system, resulting in persistent and often intense sensations of pain. It can arise from various causes, including traumatic nerve injury, neuropathy, and certain diseases. We present an overview of current and emerging pharmacotherapies for neuropathic pain, focusing on novel drug targets and potential therapeutic agents. Current pharmacotherapies, including tricyclic antidepressants, gabapentinoids, and serotonin norepinephrine re-uptake inhibitors, are discussed, as are emerging treatments, such as ambroxol, cannabidiol, and N-acetyl-L-cysteine. Additionally, the article highlights the need for further research in this field to identify new targets and develop more effective and targeted therapies for neuropathic pain management.

Inhibition of TRPA1, Endoplasmic Reticulum Stress, Human Airway Epithelial Cell Damage, and Ectopic MUC5AC Expression by Vasaka (Adhatoda vasica; Malabar Nut) Tea

This study tested whether a medicinal plant, Vasaka, typically consumed as a tea to treat respiratory malaise, could protect airway epithelial cells (AECs) from wood smoke particle-induced damage and prevent pathological mucus production. Wood/biomass smoke is a pneumotoxic air pollutant. Mucus normally protects the airways, but excessive production can obstruct airflow and cause respiratory distress. Vasaka tea pre- and co-treatment dose-dependently inhibited mucin 5AC (MUC5AC) mRNA induction by AECs treated with wood smoke particles. This correlated with transient receptor potential ankyrin-1 (TRPA1) inhibition, an attenuation of endoplasmic reticulum (ER) stress, and AEC damage/death. Induction of mRNA for anterior gradient 2, an ER chaperone/disulfide isomerase required for MUC5AC production, and TRP vanilloid-3, a gene that suppresses ER stress and wood smoke particle-induced cell death, was also attenuated. Variable inhibition of TRPA1, ER stress, and MUC5AC mRNA induction was observed using selected chemicals identified in Vasaka tea including vasicine, vasicinone, apigenin, vitexin, isovitexin, isoorientin, 9-oxoODE, and 9,10-EpOME. Apigenin and 9,10-EpOME were the most cytoprotective and mucosuppressive. Cytochrome P450 1A1 (CYP1A1) mRNA was also induced by Vasaka tea and wood smoke particles. Inhibition of CYP1A1 enhanced ER stress and MUC5AC mRNA expression, suggesting a possible role in producing protective oxylipins in stressed cells. The results provide mechanistic insights and support for the purported benefits of Vasaka tea in treating lung inflammatory conditions, raising the possibility of further development as a preventative and/or restorative therapy.

Evaluation of safety and efficacy of inhaled ambroxol in hospitalized adult patients with mucopurulent sputum and expectoration difficulty

Background

Ambroxol is a widely used mucoactive drug in sputum clearance of respiratory diseases taken orally and by injection. However, there is a paucity of evidence for inhaled ambroxol in sputum clearance.

Methods

This study performed a multicenter, randomized, double-blind, placebo-controlled, phase 3 trial at 19 centers in China. Hospitalized adult patients with mucopurulent sputum and expectoration difficulty were recruited. Patients were randomized by 1:1 to receive inhalation of either ambroxol hydrochloride solution 3 mL (22.5 mg) + 0.9% sodium chloride 3 mL or 0.9% sodium chloride 6 mL twice daily for 5 days, with an interval of more than 6 h. The primary efficacy endpoint was the absolute change in the sputum property score after treatment compared to the baseline in the intention-to-treat population.

Results

Between 10 April 2018 and 23 November 2020, 316 patients were recruited and assessed for eligibility, of whom 138 who received inhaled ambroxol and 134 who received a placebo were included. Patients who received inhaled ambroxol had a significantly greater decrease in the sputum property score compared with patients who received inhalation of placebo (difference: -0.29; 95% CI: -0.53 to -0.05; p = 0.0215). Compared with the placebo, inhaled ambroxol also significantly reduced more expectoration volume in 24 h (difference: -0.18; 95% CI: -0.34 to -0.03; p  = 0.0166). There was no significant difference in the proportion of adverse events between the two groups, and no deaths were reported.

Discussion

In hospitalized adult patients with mucopurulent sputum and expectoration difficulty, inhaled ambroxol was safe and effective for sputum clearance compared with a placebo.

Clinical trial registration

[https://www.chictr.org.cn/showproj.html?proj=184677], Chinese Clinical Trial Registry [ChiCTR2200066348].

Ambroxol for neuropathic pain: hiding in plain sight?

ABSTRACT

Ambroxol is a multifaceted drug with primarily mucoactive and secretolytic actions, along with anti-inflammatory, antioxidant, and local anaesthetic properties. It has a long history of use in the treatment of respiratory tract diseases and has shown to be efficacious in relieving sore throat. In more recent years, ambroxol has gained interest for its potential usefulness in treating neuropathic pain. Research into this area has been slow, despite clear preclinical evidence to support its primary analgesic mechanism of action-blockade of voltage-gated sodium (Na v ) channels in sensory neurons. Ambroxol is a commercially available inhibitor of Na v 1.8, a crucial player in the pathophysiology of neuropathic pain, and Na v 1.7, a particularly exciting target for the treatment of chronic pain. In this review, we discuss the analgesic mechanisms of action of ambroxol, as well as proposed synergistic properties, followed by the preclinical and clinical results of its use in the treatment of persistent pain and neuropathic pain symptoms, including trigeminal neuralgia, fibromyalgia, and complex regional pain syndrome. With its well-established safety profile, extensive preclinical and clinical drug data, and early evidence of clinical effectiveness, ambroxol is an old drug worthy of further investigation for repurposing. As a patent-expired drug, a push is needed to progress the drug to clinical trials for neuropathic pain. We encourage the pharmaceutical industry to look at patented drug formulations and take an active role in bringing an optimized version for neuropathic pain to market.

A brief review on critical analytical aspects for quantification of ambroxol in biological samples

Ambroxol (AMB) is a member of the expectorant class, widely used as a secreolytic agent in patients to break up secretions. AMB is rapidly and effectively distributed from blood to tissue. The lungs have the highest concentration of AMB; accumulation of AMB in human lung tissue was detected at concentrations 15- to 20-fold greater than those reported in the circulation. Because of its wide range of actions and therapeutic applications may be worth looking into, particularly for respiratory symptoms, antioxidant, anti-inflammatory, influenza, and rhinovirus infections. Though several analytical methodologies have been established and confirmed for the AMB analysis in matrices of pharmaceutical and biological origins, novel sustainable, and economical methods are still to be choice of protocol to increase its sensitivity, reliability, and repeatability. Therefore, the present review offers an overview of critical analytical aspects regarding the HPLC, LC-MS/MS, HPTLC, capillary electrophoresis, spectrophotometry, and electrochemical methods for quantifying AMB in pharmaceutical and biological samples. Furthermore, this review will thoroughly discuss the physicochemical properties, stability, extraction conditions, instrumentation, and operational parameters of the targeted analyte. As a result, for the first time, this review complies with vital background information and an up-to-date interpretation of research undertaken by anticipated methodologies examined and implemented for the pharmaceutical analysis AMB.

Inhibition of Clostridioides difficile Toxins TcdA and TcdB by Ambroxol

Clostridioides (C.) difficile produces the exotoxins TcdA and TcdB, which are the predominant virulence factors causing C. difficile associated disease (CDAD). TcdA and TcdB bind to target cells and are internalized via receptor-mediated endocytosis. Translocation of the toxins’ enzyme subunits from early endosomes into the cytosol depends on acidification of endosomal vesicles, which is a prerequisite for the formation of transmembrane channels. The enzyme subunits of the toxins translocate into the cytosol via these channels where they are released after auto-proteolytic cleavage. Once in the cytosol, both toxins target small GTPases of the Rho/Ras-family and inactivate them by mono-glucosylation. This in turn interferes with actin-dependent processes and ultimately leads to the breakdown of the intestinal epithelial barrier and inflammation. So far, therapeutic approaches to treat CDAD are insufficient, since conventional antibiotic therapy does not target the bacterial protein toxins, which are the causative agents for the clinical symptoms. Thus, directly targeting the exotoxins represents a promising approach for the treatment of CDAD. Lately, it was shown that ambroxol (Ax) prevents acidification of intracellular organelles. Therefore, we investigated the effect of Ax on the cytotoxic activities of TcdA and TcdB. Ax significantly reduced toxin-induced morphological changes as well as the glucosylation of Rac1 upon intoxication with TcdA and TcdB. Most surprisingly, Ax, independent of its effects on endosomal acidification, decreased the toxins’ intracellular enzyme activity, which is mediated by a catalytic glucosyltransferase domain. Considering its undoubted safety profile, Ax might be taken into account as therapeutic option in the context of CDAD.

Study on the Efficacy and Safety of Ambroxol Combined with Methylprednisolone in Patients with Acute Lung Injury

Background

There is no better treatment method towards paraquat-induced acute lung injury (ALI) at present. Ambroxol combined with methylprednisolone exhibits a significant improvement effect on ALI treatment, whereas their mechanism in ALI is still unclear.

Methods

64 patients with ALI caused by paraquat poisoning brought to our hospital from January 2015 to January 2018 were selected. They were separated into a combined treatment group (CTG) and a routine treatment group (RTG) on the basis of different treatment methods. The survival of patients was observed after 7 days of treatment. Arterial blood gas, oxygen partial pressure (PaO₂), partial pressure of carbon dioxide (PaCO₂), oxygenation index (PaO₂/FiO₂), patient's spontaneous respiratory rate (RR), tidal volume (VT), and positive end-expiratory pressure (PEEP) were observed before and after treatment for 7 days. Interleukin 6 (IL-6) and tumor necrosis factor α (TNF-α) were analyzed. The differences of indexes between the dead patients and the survivors were observed, and the potential predictive value of death was analyzed.

Results

After treatment, the indexes of patients were significantly improved in both groups compared with those before therapy. Further comparison showed that the improvement of PaO₂, PaCO₂, and PaO₂/FiO₂ in CTG was obviously higher than that in RTG (p < 0.05). The improvement of RR, PEEP, and VT in CTG was obviously higher than that in RTG (p < 0.05). The decreased degree of IL-6 and TNF-α in CTG was higher than that in RTG (p < 0.05). The 7-day mortality rate of 64 patients was 39.06%, and there was no obvious difference in the 7-day survival rate in both groups (p = 0.649). IL-6 and TNF-α were expected to be potential prediction indexes of paraquat-induced ALI.

Conclusion

Ambroxol combined with methylprednisolone significantly improved the oxygen partial pressure and oxygenation index of patients with paraquat-induced ALI and inhibited the inflammatory response of patients.

Ambroxol chaperone therapy for Gaucher disease type I-associated liver cirrhosis and portal hypertension: a case report

BACKGROUND

Gaucher disease (GD) is a rare autosomal recessive inherited disease caused by the deficiency of glucocerebrosidase and characterized by a broad spectrum of clinical manifestations, including hepatosplenomegaly, bone infiltration, and cytopenia. Moreover, it is even involved in the central nervous system. GD is classified into three phenotypes on the ground of neurologic involvement: type 1 (GD1), the commonly adult-onset, non-neuropathic variant; type 2 (GD2), the acute neuropathic form; and type 3 (GD3), the severe chronic neuro-visceral form. Recently, several studies have shown a promising outcome of ambroxol chaperone therapy for the treatment of GD, but its therapeutic role in GD1-associated liver cirrhosis and portal hypertension was not verified.

CASE PRESENTATION

A 36-year-old male patient was admitted for esophageal varices lasting for one year with a 34-year history of liver and spleen enlargement. The patient was diagnosed with GD1 with cirrhosis and portal hypertension based on the identification of Gaucher cells and advanced fibrosis in the liver biopsy tissue and two known pathogenic mutations on the glucocerebrosidase (GBA) gene. The patient received 660 mg/d of ambroxol for up to two years. At his six-month follow-up, the patient exhibited a remarkable increase in GBA activity (+35.5%) and decrease in liver stiffness (-19.5%) and portal vein diameter (-41.2%) as examined by ultrasound elastography and computer tomography, respectively. At two-year follow-up, the liver stiffness was further reduced (-55.5%) in comparison with untreated patients.

CONCLUSION

This case report suggests that long-term treatment with high dose ambroxol may play a role in the reduction of hepatic fibrosis in GD1.

Ambroxol Treatment Suppresses the Proliferation of Chlamydia pneumoniae in Murine Lungs

Ambroxol (Ax) is used as a mucolytics in the treatment of respiratory tract infections. Ax, at a general dose for humans, does not alter Chlamydia pneumoniae growth in mice. Therefore, we aimed to investigate the potential anti-chlamydial effect of Ax at a concentration four timed higher than that used in human medicine. Mice were infected with C. pneumoniae and 5-mg/kg Ax was administered orally. The number of recoverable C. pneumoniae inclusion-forming units (IFUs) in Ax-treated mice was significantly lower than that in untreated mice. mRNA expression levels of several cytokines, including interleukin 12 (IL-12), IL-23, IL-17F, interferon gamma (IFN-γ), and surfactant protein (SP)-A, increased in infected mice treated with Ax. The IFN-γ protein expression levels were also significantly higher in infected and Ax-treated mice. Furthermore, the in vitro results suggested that the ERK 1/2 activity was decreased, which is essential for the C. pneumoniae replication. SP-A and SP-D treatments significantly decreased the number of viable C. pneumoniae IFUs and significantly increased the attachment of C. pneumoniae to macrophage cells. Based on our results, a dose of 5 mg/kg of Ax exhibited an anti-chlamydial effect in mice, probably an immunomodulating effect, and may be used as supporting drug in respiratory infections caused by C. pneumoniae.

Ambroxol and Ciprofloxacin Show Activity Against SARS-CoV2 in Vero E6 Cells at Clinically-Relevant Concentrations

We studied the activity of a range of weakly basic and moderately lipophilic drugs against SARS CoV2 in Vero E6 cells, using Vero E6 survival, qPCR of viral genome and plaque forming assays. No clear relationship between their weakly basic and hydrophobic nature upon their activity was observed. However, the approved drugs ambroxol and ciprofloxacin showed potent activity at concentrations that are clinically relevant and within their known safety profiles, and so may provide potentially useful agents for preclinical and clinical studies in COVID-19.

Pharmacokinetics of Ambroxol Sustained Release (Mucosolvan® Retard) Compared with Other Formulations in Healthy Volunteers

INTRODUCTION

Ambroxol is used in the treatment of acute and chronic respiratory conditions characterized by abnormal mucus secretion and impaired mucus transport and is available in a variety of formulations. This study aimed to compare the steady-state (SS) pharmacokinetic characteristics of extended-release (ER) 75-mg retard capsules with two immediate-release (IR) formulations (60-mg effervescent tablets and 30-mg tablets) over a 24-h period.

METHODS

An open-label, randomized, three-period, six-sequence crossover study was conducted in healthy volunteers aged 18-45 years who had a normal body mass index. The test (ER 75-mg retard capsule once daily) and reference treatments (half of IR 60-mg effervescent tablet twice daily or 30-mg IR tablet twice daily) were administered on days 1-5 of each treatment period. Meals were standardized and concomitant therapy was prohibited. Blood samples for pharmacokinetic assessment were collected on day 5 (SS) of each treatment period. The co-primary endpoints were exposure (AUCSS 0-24) and maximum plasma level (Cmax SS).

RESULTS

Twenty-four participants received ambroxol (male n = 13, 54.2%; mean ± standard deviation [SD] age 25.0 ± 6.4 years) and 23 completed the study. ER retard capsules provided similar AUCSS 0-24 compared to IR tablets (geometric means ratio [GMR] 110.7%; 90% confidence interval [CI] 99.8%, 122.7%) and effervescent tablets (GMR 106.9%; 90% CI 100.3%, 114.0%). ER retard capsules provided similar Cmax SS compared to IR tablets (GMR 84.7%, 90% CI 77.0%, 93.3%), and lower Cmax SS compared to effervescent tablets (GMR 80.9%, 90% CI 73.9%, 88.6%). Time to Cmax SS (tmax SS) was longer with ER retard capsules (6.0 h) than with IR tablets (2.0 h) or effervescent tablets (1.0 h).

CONCLUSIONS

ER ambroxol 75-mg retard capsules given once daily showed a similar pharmacokinetic profile to IR ambroxol formulations and therefore can be used instead of these in the treatment of respiratory conditions. CLINICALTRIALS.

GOV IDENTIFIER

NCT02036775.

An overview of efficacy and safety of ambroxol for the treatment of acute and chronic respiratory diseases with a special regard to children

Introduction: Ambroxol (2-amino-3,5-dibromo-N-[trans-4-hydroxycyclohexyl]benzylamine), an over-the-counter product, is a mucoactive agent and has been used widely to treat both acute and chronic respiratory diseases since 1978. This review aims to provide an overview of the clinical evidence available on the use of ambroxol in children with acute and chronic respiratory diseases. Data for this review were obtained from both published and unpublished clinical studies, and real-world evidence studies. Although conducted prior to the introduction of Good Clinical Practice (GCP), these studies, representing almost 1,300 pediatric patients, report strong clinical outcomes following the use of ambroxol in pediatric patients. Furthermore, efficacy findings were consistent irrespective of age, including for patients as young as 1 month old. Additionally, the majority of studies found ambroxol to be well tolerated in children. Taken together, the clinical evidence for ambroxol shows treatment effects that offer significant benefits to pediatric patients for its licensed use as a secretolytic therapy in acute and chronic bronchopulmonary disorders associated with abnormal mucus secretion and impaired mucus transport. The findings from this review indicate that ambroxol, for its intended over-the-counter indications, is both efficacious and well tolerated in children and that the favorable benefit/risk profile of ambroxol reported in adults extends to the pediatric population, starting from early infancy, with acute and chronic respiratory diseases.

Efficacy of high-dose ambroxol for paraquat poisoning: A meta-analysis of randomized controlled trials

Background:

Paraquat (PQ) poisoning is characterized by rapidly progressive acute poisoning with high mortality and no specific antidote. Although some clinical studies have been conducted to investigate the benefits of high-dose ambroxol as an adjuvant treatment for PQ poisoning, the efficacy is controversial.

Materials and Methods:

After searching for relevant articles in English and Chinese databases from 1978 to 2019 according to the keywords (paraquat poisoning/methy viologen/gramoxone, and ambroxol/mucosolvan/Bromhexine), we found seven articles that met our inclusion and exclusion criteria. A meta-analysis was performed using fixed-effects model and random-effects model according to the I² value in Stata software (version 15.0). Four outcome indicators (hospital mortality, partial pressure of oxygen (PaO₂), oxygenation index (PaO₂/FiO₂), and survival time of the deceased patients) were of interest to us.

Results:

The meta-analysis showed that adjuvant treatment with high doses of ambroxol increased PaO₂ (weighted mean difference [WMD] = 13.73 [mmHg], 95% confidence interval [CI]: 8.68–18.79, Z = 11.80, P < 0.001), PaO₂/FiO₂ (WMD = 38.81 [mmHg], 95% CI: 29.85–47.76, Z = 8.49, P = 0.000), and survival time of the deceased patients (WMD = 2.58 [d], 95% CI: 0.97–4.18, Z = 3.15, P = 0.002) compared with usual treatment. Treatment with high doses of ambroxol also appeared to reduce the hospital mortality (relative risk = 0.69, 95% CI: 0.55–0.86, Z = 3.25, P = 0.001).

Conclusion:

This study found that high-dose ambroxol is an effective therapy for PQ poisoning and may reduce the in-hospital mortality.

Enhancement of lung levels of antibiotics by ambroxol and bromhexine

INTRODUCTION

Major unmet needs remain for improved antibiotic treatment in lung infections. While development of new antibiotics is needed to overcome resistance, other approaches to optimize therapy using existing agents are also attractive. Ambroxol induces lung autophagy at human-relevant doses and improves lung levels of several approved antibiotics. Areas covered: This review discusses preclinical and clinical studies of the effects of ambroxol (and its prodrug precursor bromhexine) co-treatment upon levels of antibiotics in lung tissue, sputum, and bronchoalveolar lavage fluid. Expert opinion: Ambroxol co-treatment is associated with significant increases in lung tissue and airway surface fluid levels of a range of antibiotics including beta lactams, glycopeptides, macrolides, nitrofurans, and rifamycins. In most cases, the increased levels are only modest and are insufficient to overcome high-level resistance against that same antibiotic class, and so co-treatment with ambroxol is unlikely to alter clinical outcomes. Additionally, for most antibiotics there is no evidence that outcomes in non-resistant disease are improved by higher drug levels, and there is limited efficacy of co-treatment of antibiotics with ambroxol for most pathogens. The two cases where ambroxol may improve therapy are rifampin-sensitive tuberculosis and non-tuberculous mycobacterial infection, and vancomycin sensitive methicillin resistant Staphylococcus aureus pneumonia.