title: Circadian rhythms and medical diseases: does it matter when drugs are taken?
abstract: BACKGROUND
  Chronobiology is devoted to the study of biological rhythms. It is possible that a given medication may be therapeutic and safe when administered at some time, but subtherapeutic or poorly tolerated at another.
  
  
  METHODS
  We focused on some classes of drugs, widely used by the internists, performing a PubMed search with the single drugs associated with the MeSH terms "Chronotherapy", "Circadian rhythm", and "Chronobiology, phenomena". Among the studies found, we considered only those provided with discrete numerosity or clearly stated methodological characteristics.
  
  
  RESULTS
  The results of available studies were given, along with a series of short take-home messages at the end of each mini-chapter devoted to: antihypertensives, statins, anticoagulants, analgesics, drugs for acid-related disorders, and anti-asthmatic drugs. In particular, evidence of morning vs. evening administration, when applicable, was given for each medication.
  
  
  CONCLUSIONS
  Adequate evidence seems to support that at least ACE-inhibitors or angiotensin receptor blockers, simvastatin, corticosteroids (slow-release formulation) for arthritic patients, and ranitidine should preferably be administered in the evening. Morning dosing could be better for proton pump inhibitors, whereas time of administration is not crucial for asthma inhalation drugs. Studies are available for other drugs, but not so strong enough to draw definite conclusions. For now, we need prospective intervention trials specifically designed to investigate the long-term effects of a temporal approach to medical therapy. However, since switching to morning-evening administration or vice versa is simple and inexpensive, in some cases it could be considered, remembering that, in any case, adherence remains the crucial point.
authors.affiliation: Clinica Medica, Azienda Ospedaliera-Universitaria, Ferrara, Italy. Electronic address: degiorgialfredo@libero.it.
authors.forename: Alfredo
authors.initials: A
authors.lastname: De Giorgi
authors.forename: Alessandra
authors.initials: A
authors.lastname: Mallozzi Menegatti
authors.forename: Fabio
authors.initials: F
authors.lastname: Fabbian
authors.forename: Francesco
authors.initials: F
authors.lastname: Portaluppi
authors.forename: Roberto
authors.initials: R
authors.lastname: Manfredini
mesh_terms: D000700:Analgesics / Q000008:administration & dosage*; D018927:Anti-Asthmatic Agents / Q000008:administration & dosage*; D000897:Anti-Ulcer Agents / Q000008:administration & dosage*; D000925:Anticoagulants / Q000008:administration & dosage*; D000959:Antihypertensive Agents / Q000008:administration & dosage*; D002940:Circadian Rhythm; D055870:Drug Chronotherapy; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000008:administration & dosage*
chemical_list: D000700:Analgesics; D018927:Anti-Asthmatic Agents; D000897:Anti-Ulcer Agents; D000925:Anticoagulants; D000959:Antihypertensive Agents; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors
keywords: Chronobiology; Chronotherapy; Circadian rhythm; Disease; Internal medicine