Editing Subcutaneous administration (section)

==Risks and complications==
With normal doses of medicine (less than 2 mL in volume), complications or adverse effects are very rare. The most common adverse reactions after subcutaneous injections are administered are termed "[[injection site reaction]]s". This term encompasses any combination of redness, swelling, itching, bruising, or other irritation that does not spread beyond the immediate vicinity of the injection.<ref name="Derm2019">{{cite journal | vauthors = Thomaidou E, Ramot Y | title = Injection site reactions with the use of biological agents | journal = Dermatologic Therapy | volume = 32 | issue = 2 | pages = e12817 | date = March 2019 | pmid = 30637967 | doi = 10.1111/dth.12817 | s2cid = 58544258 | doi-access = free }}</ref> Injection site reactions may be minimized if repeated injections are necessary by moving the injection site at least one inch from previous injections, or using a different injection location altogether.<ref name="Derm2019" /> There may also be specific complications associated with the specific medication being administered.

===Medication-specific===
Due to the frequency of injections required for the administration of insulin products via subcutaneous injection, insulin is associated with the development of [[lipohypertrophy]] and [[lipoatrophy]]. This can lead to slower or incomplete absorption from the injection site. Rotating the injection site is the primary method of preventing changes in tissue structure from insulin administration.<ref>{{cite journal | vauthors = Guo X, Wang W | title = Challenges and recent advances in the subcutaneous delivery of insulin | journal = Expert Opinion on Drug Delivery | volume = 14 | issue = 6 | pages = 727–734 | date = June 2017 | pmid = 27626885 | doi = 10.1080/17425247.2016.1232247 | name-list-style = vanc | s2cid = 19820269 }}</ref> Heparin-based anticoagulants injected subcutaneously may cause [[hematoma]] and bruising around the injection site due to their anticoagulant effect. This includes [[heparin]] and [[low molecular weight heparin]] products such as enoxaparin. There is some low certainty evidence that administering the injection more slowly may decrease the pain from heparin injections, but not the risk of or extent of bruising.<ref>{{cite journal | vauthors = Mohammady M, Radmehr M, Janani L | title = Slow versus fast subcutaneous heparin injections for prevention of bruising and site pain intensity | journal = The Cochrane Database of Systematic Reviews | volume = 2021 | issue = 6 | pages = CD008077 | date = June 2021 | pmid = 34101161 | pmc = 8186522 | doi = 10.1002/14651858.CD008077.pub6 }}</ref> Subcutaneous heparin-based anticoagulation may also lead to necrosis of the surrounding skin or lesions, most commonly when injected in the abdomen.<ref>{{cite journal | vauthors = Bilen O, Teruya J | title = Complications of anticoagulation | journal = Disease-a-Month | volume = 58 | issue = 8 | pages = 440–447 | date = August 2012 | pmid = 22818558 | doi = 10.1016/j.disamonth.2012.04.002 | name-list-style = vanc }}</ref>

Many medications have the potential to cause local lesions or swelling due to the irritating effect the medications have on the skin and subcutaneous tissues. This includes medications such as [[apomorphine]]<ref>{{cite journal | vauthors = Müller T | title = An evaluation of subcutaneous apomorphine for the treatment of Parkinson's disease | journal = Expert Opinion on Pharmacotherapy | volume = 21 | issue = 14 | pages = 1659–1665 | date = October 2020 | pmid = 32640853 | doi = 10.1080/14656566.2020.1787379 | name-list-style = vanc | s2cid = 220435665 }}</ref> and [[hyaluronic acid]] injected as a filler, which may cause the area to appear bruised. Hyaluronic acid "bruising" may be treated using injections of [[hyaluronidase]] enzyme around the location.<ref>{{cite journal | vauthors = DeLorenzi C | title = Complications of injectable fillers, part I | journal = Aesthetic Surgery Journal | volume = 33 | issue = 4 | pages = 561–575 | date = May 2013 | pmid = 23636629 | doi = 10.1177/1090820X13484492 | name-list-style = vanc | doi-access =  }}</ref>

Other common medication-specific side effects include pain, burning or stinging, warmth, rash, flushing, or multiple of these reactions at the injection site, collectively termed "injection site reactions". This is seen with the subcutaneous injection of [[triptan]]s for migraine headache,<ref>{{cite journal | vauthors = Erlichson K, Waight J | title = Therapeutic applications for subcutaneous triptans in the acute treatment of migraine | journal = Current Medical Research and Opinion | volume = 28 | issue = 7 | pages = 1231–1238 | date = July 2012 | pmid = 22401601 | doi = 10.1185/03007995.2012.674501 | name-list-style = vanc | s2cid = 10487801 }}</ref> [[medroxyprogesterone acetate]] for contraception,<ref name="Contra2016">{{cite journal | vauthors = Dragoman MV, Gaffield ME | title = The safety of subcutaneously administered depot medroxyprogesterone acetate (104mg/0.65mL): A systematic review | journal = Contraception | volume = 94 | issue = 3 | pages = 202–215 | date = September 2016 | pmid = 26874275 | doi = 10.1016/j.contraception.2016.02.003 | name-list-style = vanc | doi-access = free }}</ref> as well as many monoclonal antibodies. In most cases, injection site reactions are self-limiting and resolve on their own after a short time without treatment, and do not require the medication to be discontinued.<ref name="Contra2016" />

The administration of vaccines subcutaneously is also associated with injection site reactions. This includes the [[BCG vaccine]] which is associated with a specific scar appearance which can be used as evidence of prior vaccination.<ref>{{cite journal | vauthors = Grange JM | title = Complications of bacille Calmette-Guérin (BCG) vaccination and immunotherapy and their management | journal = Communicable Disease and Public Health | volume = 1 | issue = 2 | pages = 84–88 | date = June 1998 | pmid = 9644119 }}</ref> Other subcutaneous vaccines, many of which are live vaccines including the [[MMR vaccine]] and the [[varicella vaccine]], which may cause [[fever]] and rash, as well as a feeling of general [[malaise]] for a day or two following the vaccination.<ref>{{cite journal | vauthors = Ma SJ, Li X, Xiong YQ, Yao AL, Chen Q | title = Combination Measles-Mumps-Rubella-Varicella Vaccine in Healthy Children: A Systematic Review and Meta-analysis of Immunogenicity and Safety | journal = Medicine | volume = 94 | issue = 44 | pages = e1721 | date = November 2015 | pmid = 26554769 | pmc = 4915870 | doi = 10.1097/MD.0000000000001721 | name-list-style = vanc }}</ref>