Editing Interferon beta-1a (section)

==Side effects==
[[File:Implant.png|right|thumb|Injectable medications can produce irritation or bruises at injection site. The bruise depicted was produced by a subcutaneous injection.]]

Interferon beta-1a is available only in injectable forms, and can cause skin reactions at the injection site that may include cutaneous [[necrosis]]. Skin reactions with interferon beta are more common with subcutaneous administration and vary greatly in their clinical presentation.<ref name=pmid10563602/> They usually appear within the first month of treatment albeit their frequence and importance diminish after six months of treatment.<ref name=pmid10563602/> Skin reactions are more prevalent in women.<ref name=pmid10563602/> Mild skin reactions usually do not impede treatment whereas necroses appear in around 5% of patients and lead to the discontinuation of the therapy.<ref name=pmid10563602/> Also over time, a visible dent at the injection site due to the local destruction of fat tissue, known as [[lipoatrophy]], may develop, however, this rarely occurs with interferon treatment.<ref>{{cite journal | vauthors = Edgar CM, Brunet DG, Fenton P, McBride EV, Green P | title = Lipoatrophy in patients with multiple sclerosis on glatiramer acetate | journal = The Canadian Journal of Neurological Sciences. Le Journal Canadien des Sciences Neurologiques | volume = 31 | issue = 1 | pages = 58–63 | date = February 2004 | pmid = 15038472 | doi = 10.1017/s0317167100002845 | doi-access = free }}</ref>

[[Interferon]]s, a subclass of [[cytokines]], are produced in the body during illnesses such as [[influenza]] in order to help fight the infection. They are responsible for many of the symptoms of influenza infections, including [[fever]], [[myalgia|muscle aches]], [[fatigue (medical)|fatigue]], and [[headache]]s.<ref name="pmid16253889">{{cite journal | vauthors = Eccles R | title = Understanding the symptoms of the common cold and influenza | journal = The Lancet. Infectious Diseases | volume = 5 | issue = 11 | pages = 718–725 | date = November 2005 | pmid = 16253889 | pmc = 7185637 | doi = 10.1016/S1473-3099(05)70270-X }}</ref> Many patients report influenza-like symptoms hours after taking interferon beta that usually improve within 24 hours, being such symptoms related to the temporary increase of cytokines.<ref name="pmid18970977">{{cite journal | vauthors = Compston A, Coles A | title = Multiple sclerosis | journal = Lancet | volume = 372 | issue = 9648 | pages = 1502–1517 | date = October 2008 | pmid = 18970977 | doi = 10.1016/S0140-6736(08)61620-7 | s2cid = 195686659 }}</ref><ref name=pmid10563602>{{cite journal | vauthors = Walther EU, Hohlfeld R | title = Multiple sclerosis: side effects of interferon beta therapy and their management | journal = Neurology | volume = 53 | issue = 8 | pages = 1622–1627 | date = November 1999 | pmid = 10563602 | doi = 10.1212/wnl.53.8.1622 | s2cid = 30330292 }}</ref> This reaction tends to disappear after 3 months of treatment and its symptoms can be treated with over-the-counter [[nonsteroidal anti-inflammatory drug]]s, such as [[ibuprofen]], that reduce fever and pain.<ref name=pmid10563602/> Another common transient secondary effect with interferon-beta is a functional deterioration of already existing symptoms of the disease.<ref name=pmid10563602/> Such deterioration is similar to the one produced in MS patients due to heat, fever or stress ([[Uhthoff's phenomenon]]), usually appears within 24 hours of treatment, is more common in the initial months of treatment, and may last several days.<ref name=pmid10563602/> A symptom specially sensitive to worsening is [[spasticity]].<ref name=pmid10563602/> Interferon-beta can also reduce numbers of [[white blood cell]]s ([[leukopenia]]), [[lymphocyte]]s ([[lymphopenia]]) and [[neutrophil]]s ([[neutropenia]]), as well as affect [[liver]] function.<ref name=pmid10563602/> In most cases these effects are non-dangerous and reversible after cessation or reduction of treatment.<ref name=pmid10563602/> Nevertheless, recommendation is that all patients should be monitored through laboratory [[Blood test|blood analyses]], including [[liver function tests]], to ensure safe use of interferons.<ref name=pmid10563602/>

To help prevent injection-site reactions, patients are advised to rotate injection sites and use an aseptic injection technique. Injection devices are available to optimize the injection process.  Side effects are often onerous enough that many patients ultimately discontinue taking interferons {{citation needed|date=March 2013}} (or [[glatiramer acetate]], a comparable disease-modifying therapy requiring regular injections).