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.
Lovastatin
Lovastatin is usually well tolerated, with the most common side effects being, in approximately descending order of frequency: creatine phosphokinase elevation, flatulence, abdominal pain, constipation, diarrhoea, muscle aches or pains, nausea, indigestion, weakness, blurred vision, rash, dizziness and muscle cramps. As with all statin drugs, it can rarely cause myopathy, hepatotoxicity (liver damage), dermatomyositis or rhabdomyolysis. This can be life-threatening if not recognised and treated in time, so any unexplained muscle pain or weakness whilst on lovastatin should be promptly mentioned to the prescribing doctor. Other uncommon side effects that should be promptly mentioned to either the prescribing doctor or an emergency medical service include: