Side effect

In medicine, a side effect is an effect, whether therapeutic or adverse, that is secondary to the one intended; 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 performed specifically 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).

Examples of therapeutic side-effects

Possible side effects of nicotine.^[1]

• 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.^[2]
• Buprenorphine has been shown experimentally (1982–1995) to be effective against severe, refractory depression.^[3][4]
• Bupropion, an anti-depressant sold as Wellbutrin, 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.
• Sildenafil was originally intended for pulmonary hypertension; subsequently, it was discovered that it also produces erections, for which it was later marketed.
• Carbamazepine is an approved treatment for manic depression and convulsions, but 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.^[5]
• Dexamethasone and Betamethasone in premature labor, to enhance pulmonary maturation of the fetus.^[6]
• Doxepin has been used to treat Angiodema and severe allergic reactions due to its strong antihistamine properties.^[7]
• Gabapentin, approved for treatment of seizures and postherpetic neuralgia in adults, has side-effects which are useful in treating bipolar disorder, essential tremor, hot flashes, migraine prophylaxis, neuropathic pain syndromes, phantom limb syndrome, and restless leg syndrome.^[8]
• Hydroxyzine, an antihistamine, is also used as an anxiolytic.
• Magnesium sulfate in obstetrics for premature labor and preeclampsia.^[6]
• Methotrexate (MTX), approved for the treatment of choriocarcinoma, is frequently used for the medical treatment of an unruptured ectopic pregnancy.^[9]
• The SSRI medication sertraline is approved as an anti-depressant, but delays conjugal climax in men, and thus may be supplied to those in which climax is premature.^[10]

Examples of side effects for otoxid capsules include:

• Echinacea – more than 20 different types of reactions have been reported, including asthma attacks, loss of pregnancy, hives, swelling, aching muscles and gastrointestinal upsets.
• Feverfew – pregnant women should avoid using this herb, as it can trigger uterine contractions. In animal experiments, the use of feverfew was found to trigger spontaneous abortions (miscarriages).
• Asteraceae plants – which include feverfew, echinacea, dandelion and chamomile. Side effects include allergic dermatitis and hay fever.

References

External links

• MedEffect Canada (Health Canada)