TITLE:
Optimal needle insertion length for intramuscular injection of risperidone long-acting injectable (RLAI)
AUTHORS:
Tetsuya Tanioka, Sakiko Sakamaki, Yuko Yasuhara, Masahito Tomotake, Kensaku Takase, Chie Watari, Kouichi Makiguchi, Rozzano Locsin, Kazushi Motoki, Tatsuya Inui
KEYWORDS:
Risperidone Long-Acting Injectable; Gluteal Muscle; Intramuscular Injection; Optimal Needle Insertion Length; Body Muss Index; Ultrasonography
JOURNAL NAME:
Health,
Vol.5 No.12,
December
5,
2013
ABSTRACT: Risperidone
long-acting injectable (RLAI) is approved for the treatment of schizophrenia in
many countries. The suggested site is the gluteal muscle with a needle length
of two inches (50 mm) in Japan, which is longer than the ordinarily used needle
for intramuscular injections. The aim of this study was to determine the optimal
needle insertion length for accurate delivery of RLAI procedure among subjects
who have normal body mass index (BMI: 18 to 25) and high BMI (>25).
Thirty-seven patients with schizophrenia were administered RLAI intramuscularly
into the dorsogluteal muscle. The standard procedure required inserting 80% of
the two inch needle. By using data collected by ultrasonography, the findings
confirmed that the median needle insertion lengths for subjects with normal and
high BMI were 39.0 and 45.5 mm, respectively. To deliver RLAI effectively and
safely, the authors strongly recommend that a specialized needle be used that
is “marked” at the 40 mm point from the tip of the needle to the base. In this
way regardless of subcutaneous fat content, the RLAI can be safely delivered
into the muscle without causing untoward or side effects.