Antihistamine
The vast majority of marketed H-antihistamines are receptor antagonists and only a minority of marketed compounds are inverse agonists at the receptor. Clinically, H-antihistamines are used to treat allergic reactions and mast cell-related disorders. Sedation is a common side effect of H-antihistamines that readily cross the blood–brain barrier; some of these drugs, such as diphenhydramine and doxylamine, are therefore used to treat insomnia. H-antihistamines can also reduce inflammation, since the expression of NF-κB, the transcription factor the regulates inflammatory processes, is promoted by both the receptor's constitutive activity and agonist (i.e., histamine) binding at the H receptor.
Statin
Other possible adverse effects include neuropathy, pancreatic and liver dysfunction, and sexual dysfunction. The rate at which such events occur has been widely debated, in part because the risk/benefit ratio of statins in low-risk populations is highly dependent on the rate of adverse events. A Cochrane meta-analysis of statin clinical trials in primary prevention found no evidence of excess adverse events among those treated with statins compared to placebo. Another meta-analysis found a 39% increase in adverse events in statin treated people relative to those receiving placebo, but no increase in serious adverse events. The author of one study argued that adverse events are more common in clinical practice than in randomized clinical trials. A systematic review concluded that while clinical trial meta-analyses underestimate the rate of muscle pain associated with statin use, the rates of rhabdomyolysis are still "reassuringly low" and similar to those seen in clinical trials (about 1–2 per 10,000 person years). A systematic review co-authored by Ben Goldacre concluded that only a small fraction of side effects reported by people on statins are actually attributable to the statin.