Definitions for the level of evidence, strength of recommendation, and net benefit follow the "Major Recommendations."
- In patients with chronic bronchitis, agents that have been shown to alter mucus characteristics are not recommended for cough suppression. Level of evidence, good; benefit, none; grade of recommendation, D
- In patients with cough due to upper respiratory infection (URI) or chronic bronchitis, the only inhaled anticholinergic agent that is recommended for cough suppression is ipratropium bromide. Level of evidence, fair; benefit, substantial; grade of recommendation, A
- In patients with chronic or acute bronchitis, peripheral cough suppressants, such as levodropropizine and moguisteine, are recommended for the short-term symptomatic relief of coughing. Level of evidence, good; benefit, substantial; grade of recommendation, A
- In patients with cough due to URI, peripheral cough suppressants have limited efficacy and are not recommended for this use. Level of evidence, good; benefit, none; grade of recommendation, D
- In patients with chronic bronchitis, central cough suppressants, such as codeine and dextromethorphan, are recommended for the short-term symptomatic relief of coughing. Level of evidence, fair; benefit, intermediate; grade of recommendation, B
- In patients with cough due to URI, central cough suppressants have limited efficacy for symptomatic relief and are not recommended for this use. Level of evidence, good; benefit, none; grade of recommendation, D
- In patients with chronic or acute cough requiring symptomatic relief, drugs that affect the efferent limb of the cough reflex are not recommended. Level of evidence, low; benefit, none; grade of recommendation, D
- In patients requiring intubation during general anesthesia, the use of neuromuscular blocking agents is recommended to suppress coughing. Level of evidence, good; benefit, substantial; grade of recommendation, A
- In patients with acute cough due to the common cold, preparations containing zinc are not recommended. Level of evidence, good; benefit, none; grade of recommendation, D
- In patients with acute cough due to the common cold, over the counter combination cold medications, with the exception of an older antihistamine-decongestant, are not recommended until randomized controlled trials prove that they are effective cough suppressants. Level of evidence, fair; benefit, none; grade of recommendation: D
- In patients with acute or chronic cough not due to asthma, albuterol is not recommended. Level of evidence, good; benefit, none; grade of recommendation, D
- In patients with neuromuscular impairment, protussive pharmacologic agents are ineffective and should not be prescribed. Level of evidence, good; benefit, none; grade of recommendation, D
- In patients with bronchitis, hypertonic saline solution and erdosteine are recommended on a short-term basis to increase cough clearance. Level of evidence, good; benefit, substantial; grade of recommendation, A
- In adult patients with cystic fibrosis, amiloride is recommended to increase cough clearance. Level of evidence, good; benefit, substantial; grade of recommendation, A
- In adult patients with cystic fibrosis, while recombinant DNase does improve spirometry it is not recommended to increase cough clearance. Level of evidence, good; benefit, none; grade of recommendation, D
Definitions:
Quality of the Evidence
Good = evidence is based on good randomized controlled trials (RCTs) or meta-analyses
Fair = evidence is based on other controlled trials or RCTs with minor flaws
Low = evidence is based on nonrandomized, case-control, or other observational studies
Expert opinion = evidence is based on the consensus of the carefully selected panel of experts in the topic field. There are no studies that meet the criteria for inclusion in the literature review.
Strength of Recommendations
A = strong recommendation
B = moderate recommendation
C = weak recommendation
D = negative recommendation
I = no recommendation possible (inconclusive)
E/A = strong recommendation based on expert opinion only
E/B = moderate recommendation based on expert opinion only
E/C = weak recommendation based on expert opinion only
E/D = negative recommendation based on expert opinion only
Net Benefit
Substantial = There is evidence of benefit that clearly exceeds the minimum clinically significant benefit and evidence of little harm
Intermediate = Clear evidence of benefit but with some evidence of harms, with a net benefit between that defined for "substantial" and "small/weak"
Small/weak = There is evidence of a benefit that may not clearly exceed the minimum clinically significant benefit, or there is evidence of harms that substantially reduce (but do not eliminate) the benefit such that it may not clearly exceed the minimum clinically significant benefit
None = Evidence shows that either there is no benefit or the benefits equal the harms
Conflicting = Evidence is inconsistent with regard to benefits and/or harms such that the net benefit is uncertain
Negative = Expected harms exceed the expected benefits to the population
Table: Relationship of Strength of the Recommendations Scale to Quality of Evidence and Net Benefits
|
Net Benefit |
Quality of Evidence |
Substantial |
Intermediate |
Small/Weak |
None |
Conflicting |
Negative |
Good |
A |
A |
B |
D |
I |
D |
Fair |
A |
B |
C |
D |
I |
D |
Low |
B |
B |
C |
I |
I |
D |
Expert Opinion |
E/A |
E/B |
E/C |
I |
I |
E/D |