Silver acetate gum as a deterrent to smoking. Effects of a 2.5-mg silver acetate lozenge on initial and long-term smoking cessation. Effect of nicotine, silver acetate, and ordinary chewing gum in combination with group counselling on smoking cessation.
Silver acetate chewing gum, a nonprescription medication, produces an unpleasant metallic taste in the mouth of individuals who consume tobacco products in conjunction with this smoking deterrent. Use of the product leads to self-induced aversive conditioning. In the present double-blind controlled study, subjects using silver acetate for three weeks of treatment had a smoking cessation rate of 15 out of 136 (11 percent, p = 0.02). Placebo subjects had a smoking cessation rate of 6 out of 146 (4 percent, p = .102). Without further treatment, the group using silver acetate demonstrated a 7 percent nonsmoking rate at four months compared with a 3 percent nonsmoking rate for the placebo group. Silver acetate demonstrated a modest benefit over placebo as a smoking deterrent in a minimal intervention and highly cost-effective treatment setting. Silver acetate over-the-counter products, such as gum, lozenge, and spray, produce an aversive metallic taste when combined with cigarette smoke. Hence, they hold promise of serving as an effective smoking deterrent, one that may be used on a self-help basis.
                Five hundred adult smokers, male and female, were assigned randomly to one of two experimental conditions, 2.5-mg silver acetate lozenge and placebo lozenge. A double-blind study of the effects of a 2.5-mg silver acetate lozenge on initial (3 weeks) and long-term (12 months) smoking cessation was carried out.
                About 90% of the subjects (n = 500) reported using the lozenge (silver acetate or placebo) for smoking cessation, and they used about five lozenges per day. Over 70% of the quitters (n = 70) reported using the lozenge on an as-needed basis for relapse prevention. The overall objectively verified quit rates for subjects assigned to the silver acetate and placebo conditions at Visit 3 (3 weeks) were 17% (n = 42) and 11% (n = 28), respectively, a difference which approached statistical significance (P = 0.071). When the analysis was restricted to subjects who used the product, a statistically significant difference (P < 0.05) in initial smoking cessation emerged (26%, n = 37 vs 16%, n = 23) for subjects assigned to the silver acetate and placebo conditions. At 12 months follow-up, 26% (n = 11) of initial quitters in the silver acetate condition and 32% (n = 9) of the quitters in the placebo condition were abstinent. This difference was not statistically significant.
                The study demonstrated modest efficacy for the effect of the 2.5-mg silver acetate lozenge on initial smoking cessation for the subset of subjects who used the product as recommended. We failed to demonstrate efficacy of the lozenge for long-term relapse prevention. Additional research on the efficacy of the 2.5-mg silver acetate lozenge and long-term abstinence in general appears warranted. Four hundred and ninety six smokers participated in a randomised comparison of the effect of silver acetate, nicotine, and ordinary chewing gum on smoking cessation. All were motivated to stop smoking abruptly and all had smoked at least 10 cigarettes a day for at least five years. Side effects and taste acceptability were related to outcome after six months. The participants attended nine meetings over a year, at which lectures, support, and advice about stopping smoking were given. Tobacco abstinence was confirmed by measurement of carbon monoxide in expired air. The chewing gums were used for 12 weeks. After 12 weeks there was a trend towards more abstainers in the nicotine group (59%) than in the silver acetate (50%) and ordinary (45%) chewing gum groups that was not quite significant (p = 0.07). At 26 and 52 weeks the number of cigarette abstainers was similar in the three treatment groups. Subjects in the nicotine chewing gum group had a longer mean time before relapse than those in the silver acetate and ordinary chewing gum groups. Mean success rates for all subjects combined at 12, 26, and 52 weeks were 52.8%, 39.7%, and 23.3%. The side effects of nicotine and silver acetate chewing gum were generally mild and transient, and unimportant except for mouth irritation from silver acetate, which had a negative effect on outcome, and the low taste acceptability of nicotine, which had a strong negative influence on the success rate. The results suggest a short term effect on nicotine chewing gum on smoking cessation, but the abstinence rates after one year were generally disappointing.
Existing trials show little evidence for a specific effect of silver acetate in promoting smoking cessation. The confidence intervals for the ratio are quite wide. However, the upper limit of the confidence intervals for a positive effect equates to an absolute increase in the smoking cessation rate of about 4%. Any effect of this agent is therefore likely to be smaller than nicotine replacement therapy. The lack of effect of silver acetate may reflect poor compliance with a treatment whose rationale is to create an unpleasant stimulus.