Risk factors for complications:
(1) large volumes injected into a single site
(2) repeated injections into the same site
(3) improper technique
(3a) poor skin preparation
(3b) poor site selection
(3c) poor choice of needles
(3d) poor choice in formulation
(4) contaminated drug solutions
(5) comorbid conditions
(5a) cachexia
(5b) morbid obesity
(5c) edema
(5d) coagulopathy
Nodules may form at the injection site due to:
(1) infected abscess
(2) sterile abscess in soft tissue or muscle
(3) hematoma
(4) soft tissue granulomas
(5) oil accumulations
Other complications:
(1) significant muscle necrosis, which may be associated with elevated serum CK levels
(2) soft tissue necrosis, causing skin ulcerations
(3) bleeding
(4) pain at the injection site
(5) poor absorption of drug (due to fibrosis, leakage out, etc.)
(6) fibrosis, which may range from mild to severe with contractures
(7) injection of the drug into a blood vessel or nerve
(8) cellulitis
(9) sarcoma (late complication, fortunately rare)
(10) dystrophic calcifications
