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The effectiveness of high dose zinc acetate lozenges on various common cold symptoms: a meta-analysis.

Hemilä H, Chalker E - BMC Fam Pract (2015)

Bottom Line: Lozenges are dissolved in the pharyngeal region, thus there might be some difference in the effect of zinc lozenges on the duration of respiratory symptoms in the pharyngeal region compared with the nasal region.The effect of zinc acetate lozenges on cold symptoms may be associated with the local availability of zinc from the lozenges, with the levels being highest in the pharyngeal region.However our findings indicate that the effects of zinc ions are not limited to the pharyngeal region.

View Article: PubMed Central - PubMed

Affiliation: Department of Public Health, POB 41, University of Helsinki, Mannerheimintie 172, FIN-00014, Helsinki, Finland. harri.hemila@helsinki.fi.

ABSTRACT

Background: A previous meta-analysis found that high dose zinc acetate lozenges reduced the duration of common colds by 42%, whereas low zinc doses had no effect. Lozenges are dissolved in the pharyngeal region, thus there might be some difference in the effect of zinc lozenges on the duration of respiratory symptoms in the pharyngeal region compared with the nasal region. The objective of this study was to determine whether zinc acetate lozenges have different effects on the duration of common cold symptoms originating from different anatomical regions.

Methods: We analyzed three randomized trials on zinc acetate lozenges for the common cold administering zinc in doses of 80-92 mg/day. All three trials reported the effect of zinc on seven respiratory symptoms, and three systemic symptoms. We pooled the effects of zinc lozenges for each symptom and calculated point estimates and 95% confidence intervals (95% CI).

Results: Zinc acetate lozenges shortened the duration of nasal discharge by 34% (95% CI: 17% to 51%), nasal congestion by 37% (15% to 58%), sneezing by 22% (-1% to 45%), scratchy throat by 33% (8% to 59%), sore throat by 18% (-10% to 46%), hoarseness by 43% (3% to 83%), and cough by 46% (28% to 64%). Zinc lozenges shortened the duration of muscle ache by 54% (18% to 89%), but there was no difference in the duration of headache and fever.

Conclusions: The effect of zinc acetate lozenges on cold symptoms may be associated with the local availability of zinc from the lozenges, with the levels being highest in the pharyngeal region. However our findings indicate that the effects of zinc ions are not limited to the pharyngeal region. There is no indication that the effect of zinc lozenges on nasal symptoms is less than the effect on the symptoms of the pharyngeal region, which is more exposed to released zinc ions. Given that the adverse effects of zinc in the three trials were minor, zinc acetate lozenges releasing zinc ions at doses of about 80 mg/day may be a useful treatment for the common cold, started within 24 hours, for a time period of less than two weeks.

No MeSH data available.


Related in: MedlinePlus

The duration of the specific symptom as a proportion of the total common cold duration (set as 100%) of the placebo groups. The left side of the figure shows the duration of the symptom as a proportion of the total common cold duration, and the right side shows the same information as a forest plot. On the scale of this figure, 100% corresponds to the total duration of the common cold of the placebo groups. The duration of symptoms was calculated as follows. First, the duration of the specific symptom was calculated as the percentage of the total common cold duration for the placebo group (5.1 days in Petrus et al. [21], 8.1 days in Prasad et al. (2000) [22], and 7.1 days in Prasad et al. (2008) [23]). Then the relative duration of each specific symptom was pooled using the RevMan program. There was no heterogeneity between the three trials in the relative duration of untreated nasal discharge, sneezing, sore throat, hoarseness, muscle pain, headache, and fever with P > 0.05 for the test of heterogeneity. The relative durations of untreated nasal congestion (I2 = 85%), scratchy throat (I2 = 74%), and cough (I2 = 68%) were significantly different in the three trials. See Additional files 2 and 4 for the calculations.
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Fig5: The duration of the specific symptom as a proportion of the total common cold duration (set as 100%) of the placebo groups. The left side of the figure shows the duration of the symptom as a proportion of the total common cold duration, and the right side shows the same information as a forest plot. On the scale of this figure, 100% corresponds to the total duration of the common cold of the placebo groups. The duration of symptoms was calculated as follows. First, the duration of the specific symptom was calculated as the percentage of the total common cold duration for the placebo group (5.1 days in Petrus et al. [21], 8.1 days in Prasad et al. (2000) [22], and 7.1 days in Prasad et al. (2008) [23]). Then the relative duration of each specific symptom was pooled using the RevMan program. There was no heterogeneity between the three trials in the relative duration of untreated nasal discharge, sneezing, sore throat, hoarseness, muscle pain, headache, and fever with P > 0.05 for the test of heterogeneity. The relative durations of untreated nasal congestion (I2 = 85%), scratchy throat (I2 = 74%), and cough (I2 = 68%) were significantly different in the three trials. See Additional files 2 and 4 for the calculations.

Mentions: There is substantial variation between the mean durations of individual symptoms. For example, in the placebo group of the Prasad et al. (2008) trial, muscle ache lasted for a mean of 2.0 days, but cough lasted for 5.1 days; whereas the total duration of colds was 7.1 days (Table 3). Therefore the percentage effect of zinc on the specific symptoms should be considered together with the duration of untreated symptoms. Figure 5 shows the duration of symptoms so that they are normalized by the total duration of the colds in the three trials. For example, in the three trials, mean nasal discharge lasted for 73% (95% CI 60% to 85%) of the total common cold duration.Table 3


The effectiveness of high dose zinc acetate lozenges on various common cold symptoms: a meta-analysis.

Hemilä H, Chalker E - BMC Fam Pract (2015)

The duration of the specific symptom as a proportion of the total common cold duration (set as 100%) of the placebo groups. The left side of the figure shows the duration of the symptom as a proportion of the total common cold duration, and the right side shows the same information as a forest plot. On the scale of this figure, 100% corresponds to the total duration of the common cold of the placebo groups. The duration of symptoms was calculated as follows. First, the duration of the specific symptom was calculated as the percentage of the total common cold duration for the placebo group (5.1 days in Petrus et al. [21], 8.1 days in Prasad et al. (2000) [22], and 7.1 days in Prasad et al. (2008) [23]). Then the relative duration of each specific symptom was pooled using the RevMan program. There was no heterogeneity between the three trials in the relative duration of untreated nasal discharge, sneezing, sore throat, hoarseness, muscle pain, headache, and fever with P > 0.05 for the test of heterogeneity. The relative durations of untreated nasal congestion (I2 = 85%), scratchy throat (I2 = 74%), and cough (I2 = 68%) were significantly different in the three trials. See Additional files 2 and 4 for the calculations.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4359576&req=5

Fig5: The duration of the specific symptom as a proportion of the total common cold duration (set as 100%) of the placebo groups. The left side of the figure shows the duration of the symptom as a proportion of the total common cold duration, and the right side shows the same information as a forest plot. On the scale of this figure, 100% corresponds to the total duration of the common cold of the placebo groups. The duration of symptoms was calculated as follows. First, the duration of the specific symptom was calculated as the percentage of the total common cold duration for the placebo group (5.1 days in Petrus et al. [21], 8.1 days in Prasad et al. (2000) [22], and 7.1 days in Prasad et al. (2008) [23]). Then the relative duration of each specific symptom was pooled using the RevMan program. There was no heterogeneity between the three trials in the relative duration of untreated nasal discharge, sneezing, sore throat, hoarseness, muscle pain, headache, and fever with P > 0.05 for the test of heterogeneity. The relative durations of untreated nasal congestion (I2 = 85%), scratchy throat (I2 = 74%), and cough (I2 = 68%) were significantly different in the three trials. See Additional files 2 and 4 for the calculations.
Mentions: There is substantial variation between the mean durations of individual symptoms. For example, in the placebo group of the Prasad et al. (2008) trial, muscle ache lasted for a mean of 2.0 days, but cough lasted for 5.1 days; whereas the total duration of colds was 7.1 days (Table 3). Therefore the percentage effect of zinc on the specific symptoms should be considered together with the duration of untreated symptoms. Figure 5 shows the duration of symptoms so that they are normalized by the total duration of the colds in the three trials. For example, in the three trials, mean nasal discharge lasted for 73% (95% CI 60% to 85%) of the total common cold duration.Table 3

Bottom Line: Lozenges are dissolved in the pharyngeal region, thus there might be some difference in the effect of zinc lozenges on the duration of respiratory symptoms in the pharyngeal region compared with the nasal region.The effect of zinc acetate lozenges on cold symptoms may be associated with the local availability of zinc from the lozenges, with the levels being highest in the pharyngeal region.However our findings indicate that the effects of zinc ions are not limited to the pharyngeal region.

View Article: PubMed Central - PubMed

Affiliation: Department of Public Health, POB 41, University of Helsinki, Mannerheimintie 172, FIN-00014, Helsinki, Finland. harri.hemila@helsinki.fi.

ABSTRACT

Background: A previous meta-analysis found that high dose zinc acetate lozenges reduced the duration of common colds by 42%, whereas low zinc doses had no effect. Lozenges are dissolved in the pharyngeal region, thus there might be some difference in the effect of zinc lozenges on the duration of respiratory symptoms in the pharyngeal region compared with the nasal region. The objective of this study was to determine whether zinc acetate lozenges have different effects on the duration of common cold symptoms originating from different anatomical regions.

Methods: We analyzed three randomized trials on zinc acetate lozenges for the common cold administering zinc in doses of 80-92 mg/day. All three trials reported the effect of zinc on seven respiratory symptoms, and three systemic symptoms. We pooled the effects of zinc lozenges for each symptom and calculated point estimates and 95% confidence intervals (95% CI).

Results: Zinc acetate lozenges shortened the duration of nasal discharge by 34% (95% CI: 17% to 51%), nasal congestion by 37% (15% to 58%), sneezing by 22% (-1% to 45%), scratchy throat by 33% (8% to 59%), sore throat by 18% (-10% to 46%), hoarseness by 43% (3% to 83%), and cough by 46% (28% to 64%). Zinc lozenges shortened the duration of muscle ache by 54% (18% to 89%), but there was no difference in the duration of headache and fever.

Conclusions: The effect of zinc acetate lozenges on cold symptoms may be associated with the local availability of zinc from the lozenges, with the levels being highest in the pharyngeal region. However our findings indicate that the effects of zinc ions are not limited to the pharyngeal region. There is no indication that the effect of zinc lozenges on nasal symptoms is less than the effect on the symptoms of the pharyngeal region, which is more exposed to released zinc ions. Given that the adverse effects of zinc in the three trials were minor, zinc acetate lozenges releasing zinc ions at doses of about 80 mg/day may be a useful treatment for the common cold, started within 24 hours, for a time period of less than two weeks.

No MeSH data available.


Related in: MedlinePlus