Side effect

This article is about side effects in the context of medicine. For side effects in the context of computer science, see Side effect (computer science). For other uses, see Side effect (disambiguation).

In medicine, 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. 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 malignant tumours).

Frequency of side effects

The World Health Organization and other health organisations characterise the probability of experiencing side effects as:^[1][2]

• Very common, ≥ ¹⁄₁₀
• Common (frequent), ¹⁄₁₀ to ¹⁄₁₀₀
• Uncommon (infrequent), ¹⁄₁₀₀ to ¹⁄₁₀₀₀
• Rare, ¹⁄₁₀₀₀ to ¹⁄₁₀₀₀₀
• 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)".^[3] That is, the frequency describes how often symptoms appear after taking the drug, not caused by the drug. Both health care providers^[4] and lay people^[5] misinterpret the frequency of side effects as describing the increase in frequency caused by the drug.

Examples of therapeutic side effects

See also: Serendipity

 

Possible side effects of nicotine.^[6][7]

• Bevacizumab (Avastin), used to slow the growth of blood vessels, has been used against dry age-related macular degeneration, as well as macular edema from diseases such as diabetic retinopathy and central retinal vein occlusion.^[8]
• Buprenorphine has been shown experimentally (1982–1995) to be effective against severe, refractory depression.^[9][10]
• 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]}
• Carbamazepine is an approved treatment for bipolar disorder and epileptic seizures, but it has side effects useful in treating attention-deficit hyperactivity disorder (ADHD), schizophrenia, phantom limb syndrome, paroxysmal extreme pain disorder, neuromyotonia, and post-traumatic stress disorder.^[11]
• Dexamethasone and betamethasone in premature labor, to enhance pulmonary maturation of the fetus.^[12]
• Doxepin has been used to treat angioedema and severe allergic reactions due to its strong antihistamine properties.^[13]
• Gabapentin, approved for treatment of seizures and postherpetic neuralgia in adults, has side effects which are useful in treating bipolar disorder1, essential tremor, hot flashes, migraine prophylaxis, neuropathic pain syndromes, phantom limb syndrome, and restless leg syndrome.^[14]
• Hydroxyzine, an antihistamine, is also used as an anxiolytic.^{[citation needed]}
• Magnesium sulfate in obstetrics for premature labor and preeclampsia.^[12]
• Methotrexate (MTX), approved for the treatment of choriocarcinoma, is frequently used for the medical treatment of an unruptured ectopic pregnancy.^[15]
• 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.^[16]
• Sildenafil was originally intended for pulmonary hypertension; subsequently, it was discovered that it also produces erections, for which it was later marketed.^{[citation needed]}
• Terazosin, an α₁-adrenergic antagonist approved to treat benign prostatic hyperplasia (enlarged prostate) and hypertension, is (one of several drugs) used off-label to treat drug induced diaphoresis and hyperhidrosis (excessive sweating).^[17][18]

Examples of undesirable/unwanted side effects

Main article: Adverse effect

• Echinacea – more than 20 different types of reactions have been reported, including asthma attacks, loss of pregnancy, hives, swelling, aching muscles and gastrointestinal upsets.^[19]
• Feverfew – pregnant women should avoid using this herb, as it can trigger uterine contractions which could lead to premature labour or miscarriage.^[20]
• Asteraceae plants – which include feverfew, echinacea, dandelion and chamomile. Side effects include allergic dermatitis and hay fever.^{[citation needed]}

See also

• Paradoxical reaction, an effect of a substance opposite to what would usually be expected.
• Pharmacogenetics, the use of genetic information to determine which type of drugs will work best for a patient

References

1. "Common and Rare Side Effects for misoprostol oral".
2. "Definitions" (PDF). (PDF) from the original on 4 March 2016. Retrieved 29 April 2016.
3. "A Guideline on Summary of Product Characteristics" (PDF). European commission. 1 September 2009.
4. Mühlbauer V, Mühlhauser I (November 2015). "Understanding adverse drug reactions in package leaflets - an exploratory survey among health care professionals". BMC Health Services Research. 15 (1): 505. doi:10.1186/s12913-015-1160-1. PMC 4641349. PMID 26554666.
5. Mühlbauer V, Prinz R, Mühlhauser I, Wegwarth O (13 September 2018). "Alternative package leaflets improve people's understanding of drug side effects-A randomized controlled exploratory survey". PLOS ONE. 13 (9): e0203800. Bibcode:2018PLoSO..1303800M. doi:10.1371/journal.pone.0203800. PMC 6136776. PMID 30212555.
6. "Nicotine Side Effects". Drugs.com.
7. Schraufnagel DE, Blasi F, Drummond MB, Lam DC, Latif E, Rosen MJ, et al. (September 2014). "Electronic cigarettes. A position statement of the forum of international respiratory societies". American Journal of Respiratory and Critical Care Medicine. 190 (6): 611–8. doi:10.1164/rccm.201407-1198PP. PMID 25006874. S2CID 43763340.
8. Boseley S (17 June 2006). "Drugs firm blocks cheap blindness cure". The Guardian. London. Retrieved 20 May 2010.
9. Gracer R (February 2007). "The Buprenorphine Effect on Depression" (PDF). naabt.org. National Alliance of Advocates for Buprenorphine Treatment. Retrieved 19 September 2015.
10. 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. PMID 7714228.
11. Leehey K (1 August 2003). . Leeheymd.com. Archived from the original on 13 November 2011. Retrieved 17 August 2011.
12. Wing 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. PMID 20308845.
13. Shen WW, Mahadevan J, Hofstatter L, Sata LS (July 1983). "Doxepin as a potent H2 and H2 antihistamine for epigastric distress". The American Journal of Psychiatry. 140 (7): 957–8. doi:10.1176/ajp.140.7.957. PMID 6859336. Archived from the original on 4 September 2011.
14. (PDF). Idaho Drug Utilization Review, educational leaflet. 2004. Archived from the original (PDF) on 9 August 2007.
15. . drugs.nmihi.com. (New Medical Information and Health Information). Archived from the original on 11 October 2008.
16. Deem SG. "Premature Ejaculation". Emedicine.com. from the original on 1 December 2008. Retrieved 17 August 2011.
17. Gelenberg AJ, Freeman MP, Markowitz JC, Rosenbaum JF, Thase ME, Trivedi MH, Silbersweig DA (2010). "Practice guideline for the treatment of patients with major depressive disorder" (PDF). Am J Psychiatry. American Psychiatric Association. 167 (Suppl 10): 9–118.{{cite journal}}: CS1 maint: date and year (link)
18. Cheshire WP, Fealey RD (2008). "Drug-induced hyperhidrosis and hypohidrosis: incidence, prevention and management". Drug Safety. 31 (2): 109–26. doi:10.2165/00002018-200831020-00002. PMID 18217788. S2CID 23041000.
19. "Filagra Vs Fildena". Filagra100mg.com. 23 February 2017. from the original on 3 July 2017.
20. 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. PMID 27002079. S2CID 10098257.

External links

• "MedEffect Canada". Health Canada.
• "Definitions" (PDF). World Health Organisation.

de