Tissue irritation intramuscular injection sites

Diclofenac is a phenylacetic acid derivative used mainly as sodium salt for the treatment of various pain and inflammation. Intramuscular injection occasionally causes tissue damage at the injection site. Suppositories may cause local irritation transient burning and stinging are reported when used for the eye and large doses can cause aplastic anemia.14... 

One disadvantage is that intramuscular injection can result in localized (at the site of injection) pain. Furthermore, when drugs arc administered intramuscularly by a person who is not formally trained to do so, the risk of infection from irritating drugs and tissue damage is high. 

One somewhat different, but critical, parameter in animal health sterile products compared with human health care products is the irritation and residue at the injection site. For companion animals, the pain upon injection should be minimal, and any lasting reactions that cause either pain or visual lumps to a pet will not be tolerated by many owners. For food-producing animals such as cattle, pigs, and poultry, the added challenge is that of ensuring the residue levels at the injection site have been depleted adequately by the time the animal is harvested. The formulation scientist thus may need to carefully observe the viscosity and polarity of the vehicle as they can affect residue times. Volumes injected and the route can also have an impact. Oftentimes subcutaneous administration is used instead of intramuscular administration to minimize residues in the tissue and potential damage to meat (i.e., muscle). 

Intramuscular injections are performed deep into the skeletal muscles at either the deltoid, gluteal, or lumbar muscles. The site is chosen to minimize danger of hitting a nerve or blood vessel. Aqueous or oleaginous solutions or suspensions may be used with rapid effects or depot activity selected to meet the requirements of the patient. Drugs that are irritating to subcutaneous tissue are often administered intramuscularly with volumes of 2 to 5 mL or more. When a volume of 5 mL or more is to be injected it should be in divided doses using two injections. 

An intramuscular (IM) injection is the administration of a drug into a muscle (see Pig. 2-5C). Dru that are irritating to SC tissue can be given via IM injection. Dru given by this route are absorbed more rapidly than dru given by the SC route because of the rich blood supply in the muscla In addition, a larger volume (1-3 inL) can be given at one site. 

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