Inmedicine, a side effect is an effect, whether therapeutic or adverse, that is unintended; although the term is predominantly employed to describe adverse effects, it can also apply to beneficial, but unintended, consequences of the use of a drug.
Occasionally, drugs are prescribed or procedures are performed for their side effects; in that case, said side effect ceases to be a side effect and is now an intended effect.[1] For instance, X-rays were historically (and are currently) used as an imaging technique; the discovery of their oncolytic capability led to their employ in radiotherapy (ablation of malignanttumours).
The World Health Organization and other health organisations characterise the probability of experiencing side effects as:[2][3]
Very common, ≥ 1⁄10
Common (frequent), 1⁄10to1⁄100
Uncommon (infrequent), 1⁄100to1⁄1000
Rare, 1⁄1000to1⁄10000
Very rare, < 1⁄10000
The European Commission recommends that the list should contain only effects where "at least a reasonable possibility" exists that it is caused by the drug and the frequency "should represent crude incidence rates (and not differences or relative risks calculated against placebo or other comparator)".[4] That is, the frequency describes how often symptoms appear after taking the drug, not caused by the drug. Both health care providers[5] and lay people[6] misinterpret the frequency of side effects as describing the increase in frequency caused by the drug.
Buprenorphine has been shown experimentally (1982–1995) to be effective against severe, refractory depression.[10][11]
Bupropion (Wellbutrin), an anti-depressant, is also used as a smoking cessation aid; this indication was later approved, and the name of the smoking cessation product is Zyban. In Ontario, Canada, smoking cessation drugs are not covered by provincial drug plans; elsewhere, Zyban is priced higher than Wellbutrin, despite being the same drug. Therefore, some physicians prescribe Wellbutrin for both indications.[citation needed]
The SSRI medication sertraline is approved as an antidepressant but delays conjugal climax in men, and thus may be supplied to those in which climax is premature.[17]
Echinacea – numerous potential reactions may occur, including allergic reactions, hives, swelling of the face, aching muscles and gastrointestinal discomfort.[20]
Feverfew – pregnant women should avoid using this herb, as it can trigger uterine contractions which could lead to premature labour or miscarriage.[21]
^Gracer R (February 2007). "The Buprenorphine Effect on Depression"(PDF). naabt.org. National Alliance of Advocates for Buprenorphine Treatment. Retrieved 19 September 2015.
^Bodkin JA, Zornberg GL, Lukas SE, Cole JO (February 1995). "Buprenorphine treatment of refractory depression". Journal of Clinical Psychopharmacology. 15 (1): 49–57. doi:10.1097/00004714-199502000-00008. PMID7714228.
^ abWing DA, Powers B, Hickok D (April 2010). "U.S. Food and Drug Administration drug approval: slow advances in obstetric care in the United States". Obstetrics and Gynecology. 115 (4): 825–833. doi:10.1097/AOG.0b013e3181d53843. PMID20308845.
^Wells RE, Turner DP, Lee M, Bishop L, Strauss L (April 2016). "Managing Migraine During Pregnancy and Lactation". Current Neurology and Neuroscience Reports. 16 (4): 40. doi:10.1007/s11910-016-0634-9. PMID27002079. S2CID10098257.
