Letosteine

Letosteine has been found to be effective in treating patients with chronic bronchopneumopathies in clinical practice. To provide robust support for its pharmacokinetic and clinical studies, a rapid and sensitive method based on liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) was developed and validated for the analysis of letosteine in plasma samples. After protein precipitation, the plasma samples were separated on a reversed-phase C(18) column in less than 1.5 min. The LC-MS/MS system was performed in the positive ion multiple-reaction-monitoring (MRM) mode to produce intensive product ions of m/z 280.1→160.0 for letosteine and m/z 248.1→121.1 for the internal standard, tinidazole. The method was found to have excellent linearity (r ≥ 0.9974), precision (RSD ≤ 5.83%), extraction recovery (71.8-73.0%) and stability (RE, -8.45% to 9.03%) over a concentration range of 0.1140-152.0 μgL(-1). Compared to the previous published radioactive method, LC-MS/MS method showed many advantages including shorter analysis time, simpler preparation procedure, increased sensitivity as well as lower safety risks. In addition, this method was successfully applied to study the pharmacokinetics of letosteine following a single and multiple dose oral administration in Chinese healthy volunteers.

To review the seven Cochrane reviews of non-antibiotic treatment for the common cold.

Each Cochrane review was read and summarized, and results presented as relative risks and, where possible, numbers needed to treat.

The main theme that runs through these Cochrane reviews is the variable quality of the primary studies. In general, the reviewers are fairly cautious about the benefits of any of the treatments other than first-dose decongestants and antihistamine-decongestant combinations. For antihistamines alone, the reviewers were clear about the lack of efficacy except in the high-quality studies in which a global improvement in symptoms was noted. Some studies were statistically significant, but the Cochrane reviewers were guarded about how clinically significant they were. For Echinacea, problems were found with the quality of the studies and the wide range of different forms of this substance. Heated humidified air seemed to be effective in the UK and Israel, but not the USA, making definitive statements about efficacy difficult. Over-the-counter medication for cough seemed to have no documented benefit in children under the age of 5 years. Letosteine (a mucolytic) may be effective in children but is not available in the UK. Bisolvon (a mucolytic) was found to be effective for cough in only one study. For older children and adults, dextromethorphan may be effective (two out of three studies showed benefit), and guiafenesin (an expectorant) showed mixed benefit in two trials. Dexbrompheniramine (a sedating antihistamine)/pseudoephedrine (6 mg/120 mg twice daily for 1 week) was significantly more effective than placebo for severity of cough, whereas, in another study, loratadine (a non-sedating antihistamine)/pseudoephedrine (5 mg/120 mg twice daily for 4 days) did not show any difference between the study groups. Vitamin C may have a small role in preventing the common cold, with possibly a greater role in high-intensity physical activity and sub-arctic conditions. Zinc lozenges seemed to be effective, but the issue of unblinding due to taste was a methodological issue of concern to the reviewers. The benefits and harms are calculated as numbers needed to treat for one person to benefit (NNTB) and numbers needed to treat for one person to harm (NNTH), and were calculated by the author.

Most non-antibiotic treatments for the common cold are probably not effective. The most promising are dextromethorphan, bisolvon and guiaphenesin for cough, antihistamine-decongestant combinations for a wide range of symptoms, nasal decongestants (at least for the first dose) and possibly zinc lozenges.