Discussions about loss of effectiveness of head lice drugs containing pyrethrin or pyrethroid due to possible development of resistance are frequently published. However, in 2016, a randomized controlled comparative study of 107 children with acute lice infestation showed, for the first time and with high-level evidence, that Goldgeist forte (pyrethrum extract) continues to achieve high healing rates: adjusted to reinfestation, the rate of healing after two treatments was as high as 94% (1). The comparative test product in this study was the medical product Mosquito Med Läuseshampoo 10 (head lice Shampoo 10), with a 96.1% healing rate after 10 days. This slightly higher healing rate was not statistically significant. Both products were well tolerated. The article by Meister et al. (2) did not include this recent study but should do so, as it makes an important contribution to the future discussion of differences in the efficacy of medicinal devices and medicinal products.
The study also examined the efficacy of Goldgeist forte for the first time in the original formulation approved for Germany. For example, Goldgeist forte contains a pyrethrum formulation with a total of six different active pyrethrin compounds. The ratio of these are standardized and produces a wider range of activity, which first paralyzes (knock-down effect) and then kills (kill effect) head lice.
In addition, pyrethrum synergizes in Goldgeist forte with the antioxidant piperonyl butoxide, which is known to be a resistance breaker. The combination of these specific formulations allow Goldgeist forte to remain clinically effective against lice that have genetic mutations making them resistant to knock-down. However, the corresponding resistance mechanisms do not necessarily lead to loss of efficacy in pyrethrin- and pyrethroid-based drugs, as has been demonstrated earlier in application observations and in two randomized controlled studies carried out by the University of Kiel (3).
Footnotes
Conflict of interest statement
The author is the head of quality control at the company Eduard Gerlach GmbH, which produces Goldgeist forte.
References
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