The absolute risk reduction associated with acetazolamide prophylaxis was associated with the risk

of AMS in the trial placebo group and with the rate of ascent but not the maximum altitude reached. The lack of association with maximum altitude is not surprising, as rate of ascent was variable and in all but two studies the maximum height reached was between 4,000 and 5,000 m. This does not exclude the possibility of an association if a greater range of maximum Natural Product Library altitudes had been studied. There was an association between a study’s representative rate of ascent and absolute benefit from acetazolamide. This means that as rate of ascent increases, the NNT from acetazolamide prophylaxis decreases. This finding is plausible but should be interpreted with caution. The rate of ascent is only approximate and particularly in the location-based studies is difficult

Vorinostat mouse to define. Furthermore, since the expedition-based studies had a higher rate of climb than the location-based studies, these differences could be confounded by other differences in the trial design rather than rate of ascent. The association between rate of climb and benefit from acetazolamide could only be definitively established by a properly controlled trial with randomized rates of ascent. Adverse effects were not systematically described in the majority of studies and this made firm conclusions about the incidence of these adverse events difficult. Many studies reported only the lack of serious adverse events. It is clear, however, that adverse effects are common but generally mild. In the studies systematically reporting adverse effects, paraesthesia was most commonly reported. There were, however, insufficient data in this analysis to investigate any association between dose and adverse effects. This question Farnesyltransferase was addressed in one of the studies, which concluded that adverse effects were more

common in the 750 mg/d group.[33] There are a number of limitations to our analysis. We decided to include in our analysis only studies involving acetazolamide. This study does not address the efficacy of other medications for the prophylaxis of AMS, such as dexamethasone, ibuprofen, and gingko balboa. A review on this broader question of the role of other pharmacological strategies has recently been published.[47] Since many of the early studies of acetazolamide in AMS were carried out many decades ago, it is likely that we have not identified all the studies which could have potentially been included. We were also unable to obtain the text of one study. However, given that this study and any possible unidentified studies are likely to be small, it is unlikely that they would have significantly altered this analysis. Our inclusion criteria were intentionally narrow, resulting in the exclusion of a significant number of trials.