Table 3:
Alternative and nonpharmacologic interventions for the treatment of the common cold
| Intervention | Formulation and dose | Evidence | Risk of bias | Outcome | Harms | Comment |
|---|---|---|---|---|---|---|
| Honey71–73 | 2.5–10 mg, one dose at bedtime | 3 RCTs (n = 105, 139 and 300 children, respectively); most aged 1–5 yr | Moderate (multiple trial quality issues, but results highly consistent) | Evidence of benefit over placebo and dextromethorphan | No consistent adverse events | Small benefit for cough in children (age > 1 yr); no data for adults |
| Zinc, oral74 | Different formulations, doses, frequency; zinc gluconate 23-mg lozenge every 2 h most common | Meta-analysis (17 RCTs, n = 2121) | Moderate (high or moderate risk of bias in many studies) | Pooled analysis of 8 RCTs: reduced duration of cold (mean difference −1.65 d, 95% CI −2.5 to −0.8) | Increased adverse events (bad taste and nausea) | Probable benefit in adults, but harms present; no benefit in children |
| Nasal irrigation75 | Generally, saline drops (children) or irrigation | Systematic review and meta-analysis (3 RCTs, n = 618) | High (multiple outcomes, most nonsignificant, and quality issues in RCTs) | Pooled analysis of 2 RCTs: no difference in nasal symptom score; other results inconsistent | 13% nasal irritation, 30% dry nose, 40% of infants intolerant of nasal drops | Unclear benefit |
| Humidified air76 | Heated water (42°C–47°C ), vapourized | Systematic review and meta-analysis (6 RCTs, n = 394) | Moderate (unclear allocation concealment and mixed results) | Pooled analysis of 2 RCTs: fewer participants with persistent symptoms (Peto OR 0.31, 95% CI 0.16 to 0.60); very inconsistent results (I2 = 89%) | Increased harms, including mask discomfort and increased nasal congestion | Unclear benefit |
| Echinacea50 | Variable formulations and dosing; E. purpurea most common | Systematic review (14 RCTs, n = 2090) | Moderate (some trial quality issues, and inconsistent formulations, cold definitions and results) | Inconsistent results (not pooled); for example, 1 of 6 studies showed improved duration and severity of symptoms | No evidence of harms | Unclear benefit |
| Chinese medicinal herbs77 | Various formulations | Systematic review (17 RCTs, n = 3212) | High (poor trial quality) | Data not pooled; 1 of 17 RCTs showed improved severity of symptoms | Not reported | Unclear (likely no) benefit |
| Ginseng78 | North American ginseng extract in standard dose (26 mg/kg on day 1, 17 mg/kg on day 2, 9 mg/kg on day 3) v. low dose (half the amounts on each day) v. placebo | 1 RCT (n = 46 children aged 3–12 yr) | Low (high-quality trial) | No effects reported | No increase in adverse events | Unclear benefit |
| Vitamin C47 | 1.5–4 g for 1–5 d | Meta-analysis (7 trials, n = 3294 colds) | Moderate (reviewers used blinding as a surrogate of allocation concealment) | Pooled analysis of 7 RCTs: no effect on duration | No evidence of harms | No benefit |
| Zinc, intranasal79,80 | Zinc nasal spray 33 mmol/L, each nostril 4 times daily (2.1 mg total) in 2 of 3 studies | Meta-analysis (3 studies, n = 453) | Moderate (high heterogeneity, possible nonblinding and poor description of randomization) | Pooled analysis of 3 RCTs: no significant effect on presence of symptoms at day 3 | Nasal burning and stinging; unresolved concern of permanent loss of smell | Do not use (unclear benefit and possible serious harm may exist) |
Note: CI = confidence interval, OR = odds ratio, RCT = randomized control trial, RR = rate ratio.