Injection (medicine)
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224188899
2008-07-07T18:53:20Z
Lizwalk
7372002
An '''injection''' is an [[route of administration|infusion method]] of putting [[liquid]] into the [[body]], usually with with a hollow [[hypodermic needle|needle]] and a [[syringe]] which is pierced through the skin to a sufficient depth for the material to be forced into the body. An injection follows a parenteral route of administration, that is, its effect is not necessarily local to the area in which the injection is administered; it is systemic.
[[Image:OuchFlintGoodrichShot1941.jpg|right|thumb|200px|Hypodermic syringe injection]]
There are several methods of injection or infusion, including intradermal, subcutaneous, [[intramuscular injection|intramuscular]], [[intravenous]], [[intraosseous]], and [[intraperitoneal]]. Long-acting forms of subcutaneous/intramuscular injections are available for various drugs, and are called depot injections.
== Intravenous infusion ==
[[Image:Injection 23.JPG|A medicine being administered intravenously through a [[Intravenous therapy#Peripheral IV lines|peripheral IV line]].|250px|thumb|right]]
{{main|Intravenous therapy}}
An [[intravenous therapy|intravenous infusion]] is a liquid administered directly into the bloodstream via a vein. The first [[polio vaccine]] in 1952 was injected intravenously until an oral [[vaccine]] replaced it in 1955.
When a rapid onset of action is needed, medications may be administered intravenously, intramuscularly, under the tongue ([[sublingual]]), or by intranasal or oral inhalation ([[insufflation]]).
== Subcutaneous injection ==
A subcutaneous injection is administered as a [[bolus (medicine)|bolus]] into the [[subcutis]], the layer of skin directly below the [[dermis]] and [[Epidermis (skin)|epidermis]], collectively referred to as the [[cutis]]. Subcutaneous injections are highly effective in administering vaccines and such medications as [[insulin]], [[morphine]], [[heroin|diacetylmorphine]] or [[goserelin]].
An injection port such as the [[I-port]] can be used to minimize skin punctures for people taking multiple daily injections.
[[Image:Insulin pump with infusion set.jpg|thumb|left|An [[insulin pump]] with a subcutaneous injection site.]]A person with Type I [[diabetes mellitus]] typically injects insulin subcutaneously. Places on the body where people can inject insulin most easily are:
* The outer area of the [[upper arm]].
* Just above and below the [[waist]], except the area right around the [[navel]] (a 2-inch circle).
* The upper area of the [[buttock]], just behind the [[pelvis|hip bone]].
* The front of the [[thigh]], midway to the outer side, 4 inches below the top of the thigh to 4 inches above the knee.
These areas can vary with the size of the person. Changing the injection site keeps lumps or small dents called [[lipodystrophy|lipodystrophies]] from forming in the skin. However, people should try to use the same body area for injections that are given at the same time each day-for example, always using the [[abdomen]] for the morning injection or an arm for the evening injection{{Fact|date=February 2007}}. Using the same body area for these routine injections lessens the possibility of changes in the timing and action of insulin.{{Fact|date=February 2007}}
== Intramuscular injection ==
{{main|Intramuscular injection}}
In an '''intramuscular injection''', the medication is delivered directly into a [[muscle]]. Many [[vaccine]]s are administered intramuscularly, as well as [[codeine]], [[metoclopramide]], and many other medications. Many drugs injected intramuscularly are absorbed into the muscle fairly quickly, while others are more gradual.
Generally, intramuscular injections are not [[self-administer]]ed, but rather by a trained [[medical professional]]. However, prescribed self-administered intramuscular injections are becoming more common for patients that require these injections routinely.
==Depot injection==<!-- This section is linked from [[Birth control]] -->
[[Image:Implant.png| 250px |thumb|right|A typical site post subcutaneous injection (navel area). The entry wound and implant ejection bruise can clearly be seen here]]
A depot injection is an injection, usually subcutaneous or intramuscular, of a pharmacological agent which releases its active compound in a consistent way over a long period of time. Depot injections are usually either solid or oil-based. Depot injections may be available as certain forms of a drug, such as [[decanoic acid|decanoate]] salts or esters. Examples of depot injections include [[Depo Provera]] and [[haloperidol]] decanoate.
The advantages of using a long-acting depot injection include increased [[Compliance (medicine)|medication compliance]] due to reduction in the frequency of dosing, as well as more consistent serum concentrations. However, one significant disadvantage of using a depot injection is that the drug is not immediately reversible, since it is slowly released.
==Hypodermic injections in nature==
Various animals, and some plants, have been injecting for various reasons long before humans began doing so. This process is often called [[stinger (organ)|stinging]].
Some examples include:
*[[Snake]]s, [[wasp]]s, [[scorpion]]s: poison, to kill prey and self-defense.
*Some [[bee]]s: poison, for self-defense and to defend their nests.
*[[Coelenterate]]s: poison, to kill prey.
*[[Stinging nettle]]s: poison, to try to avoid being eaten.
==Injection pain==
The pain of an injection may be lessened by prior application of ice or topical anesthetic or simultaneous pinching of the skin. Recent studies suggest that forced coughing during an injection stimulates a transient rise in blood pressure which inhibits the perception of pain. Sometimes, as with an [[amniocentesis]], a local anesthetic is given. <ref>Anesthesia and Analgesia 2004;98:343-5</ref> The most common technique to reduce the pain of an injection is simply to distract the patient.
==References==
{{reflist}}
== See also ==
* [[Intracardiac injection]]
* [[Intraosseous infusion]]
* [[Medication]]
* [[Occupational Safety and Health Administration]] (OSHA)
* [[Vaccine]]
* [[Dart injection]]
* [[Jet injector]]
== External links ==
*[http://www.simmed.com/Demo/Default.aspx Animated Intramuscular Injection tutorial]
*[http://www.fda.gov/cder/dsm/DRG/drg00301.htm FDA Center for Drug Evaluation and Research Data Standards Manual: Route of Administration.]
*[http://www.healthinfotranslations.com/subcutaneous_injection_sites_988289.php Subcutaneous Injection Sites - from healthinfotranslations.com]
*[http://www.healthinfotranslations.com/giving_medicine_by_subcutaneous_injection_389432.php Giving Medicine by Subcutaneous Injection - from healthinfotranslations.com]
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[[Category:Pharmacology]]
[[Category:Dosage forms]]
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