Deltoid Injections Research Articles

Considering skin-to-muscle depth for successful intramuscular injections in an increasingly obese population.

Intramuscular (IM) injection practice is an essential nursing skill. Current practice relies on clinical judgement to determine needle length (unless specified in the medicine's product licence). Obesity is increasing in the global population, but guidelines have largely ignored how to select needle length to meet individual patient need. The aim of this review was to systematically review the skin-to-muscle depth required to achieve injection into muscle in adults. The objectives were to identify any implications of obesity status when selecting an appropriate needle length and site in clinical practice. Search and review methodology: Studies of subjects above the age of 18 years using observational or experimental designs where the distance from the skin to muscle had been measured at any IM injection site, and obesity status was reported, were included in the search strategy. The primary outcome of interest was the distance from skin surface to muscle penetration. 14 studies were identified that investigated the dorsogluteal, ventrogluteal, deltoid and vastus lateralis sites, all used cross-sectional observational designs. Ten used ultrasound, three used computed tomography (CT) and one used magnetic resonance imaging. Obesity status was reported as BMI or hip-to-waist ratio. In all studies there was a correlation between obesity status and the distance from skin surface to muscle. In females this exceeded 37 mm at both gluteal sites, independent of obesity status. There should be an assessment of obesity status before selecting needle length for IM injections in both genders. Needles longer than the standard 37 mm are recommended for all females, whatever their obesity status, for any gluteal site. Injections into gluteal sites should be avoided in females who are obese. Deltoid injections are more likely to achieve muscle penetration in both genders, and in patients who are overweight or obese. Further research is required.

Establishment of prediction equations for subcutaneous tissue thickness in two representative intramuscular deltoid injections

This study clarifies the predicted subcutaneous shoulder depth and investigates the safety of the conventional (three-finger breadth method) and new (axillary method) intramuscular injection methods. The anatomical features of 245 volunteers who received the COVID-19 vaccination via the conventional method were investigated at the injection site (T point) and the hypothetical injection site using the new method (A point) via ultrasonography. The body mass index (BMI) and subcutaneous thickness at the T point (men: r = 0.75; women: r = 0.45) and the A point (men: r = 0.81; women: r = 0.55) were positively correlated. The upper arm circumference and subcutaneous thickness at the T point (r = 0.51) and the A point (r = 0.58) were correlated in women. Formulas to predict subcutaneous thickness using BMI and upper arm circumference were established: predicted subcutaneous thickness at the A point = 0.62 × BMI − 7.7 mm (R2 = 0.66) in men and 0.658 × BMI − 5.5 mm (R2 = 0.31) in women. This study demonstrates safe intramuscular injection sites and their depth.

Botulinum neurotoxin injection in the deltoid muscle: application to cosmetic shoulder contouring.

This study describes the intramuscular nerve branching of the deltoid muscle in relation to shoulder surface anatomy, with the aim of providing essential information regarding the most appropriate sites for botulinum neurotoxin injection during shoulder line contouring. The modified Sihler's method was used to stain the deltoid muscles (16 specimens). The intramuscular arborization areas of the specimens were demarcated using the marginal line of the muscle origin and the line connecting the anterior and posterior upper edges of the axillary region. The intramuscular neural distribution of the deltoid muscle had the greatest arborization patterns in the area between the horizontal 1/3 and 2/3 lines of the anterior and posterior deltoid bellies, and 2/3 to axillary line in middle deltoid bellies. The greatest part of the posterior circumflex artery and axillary nerve ran below the areas with the highest aborizations. We propose that botulinum neurotoxin injections should be administered in the area between the 1/3 and 2/3 lines of the anterior and posterior deltoid bellies, and 2/3 to axillary line on middle deltoid bellies. Accordingly, clinicians will ensure minimal dose injections and fewer adverse effects of the botulinum neurotoxin injection. Deltoid intramuscular injections, such as vaccines and trigger point injections, should ideally be adapted according to our results.

Thickness of the Deltoid Muscle and Location of the Anterior Branch of the Axillary Nerve and the Posterior Circumflex Humeral Artery for Deltoid Injections.

This study investigated the thickness of the deltoid muscle and the location of the anterior branch of the axillary nerve (AAN) and posterior circumflex humeral artery (PCHA), with the goal of maximizing the effectiveness of deltoid injections. Forty specimens from 22 adult Korean cadavers were used. A reference line was identified, connecting the anterior point of the deltoid muscle (AP) and the posterior point of the deltoid muscle (PP) on the surface. The midpoint between the AP and PP was used as the origin point (OP). The line connecting the OP and the lowest point of the deltoid tuberosity (DP) was used as the y-axis. The mean distance of the reference line from the AP to PP was 4.7 ± 0.7 cm. The vertical mean length of the deltoid muscle from the OP and DP was 16.1 ± 1.0 cm. At the 3, 5, and 7 cm sites, the thickness of the deltoid muscle was 0.62 ± 0.9, 0.73 ± 0.7, and 1.3 ± 1.1 cm, respectively. Most of the branches of the axillary nerve were concentrated in the third section (4-6 cm, 51%), while the branches of the PCHA were predominantly found in the fourth section (6-8 cm, 69%). The peripheral branches of the AAN entering the muscle were distributed between 2.2 and 9.8 cm from the acromion. The mean number of the peripheral branches of the AAN was 9.6 ± 3.4. In the deltoid muscle, the mean number of peripheral branches of the PCHA was 8.2 ± 2.8. Administering deltoid injections 5-6 cm below the OP is recommended to avoid axillary nerve injury.

Deltoid Intramuscular Injections: A Systematic Review of Underlying Neurovascular Structures to the Muscle and Proposing a Relatively Safer Site.

The deltoid is the preferred site for intramuscular injection (IMI) because of its easy accessibility for drug and vaccine administration. Government immunization advisories, standard anatomy textbooks, and researchers have proposed various injection techniques and sites, but specific guidelines are lacking for the administration of IMIs in the increasingly used deltoid site. This study analyzes the procedures of administering IMIs in the deltoid related to the neurovascular network underlying the muscle and proposes a preferred site with the least chance of injury. The review protocol was submitted with PROSPERO (ID: 319251). PubMed, Google Scholar, and Websites of National Public Health Agencies were searched from 1950 up to 2022 for articles, advisories, and National Immunization Guidelines using Medical Subject Headings (MeSH) terms, including IMIs, deltoid muscle, safe injection sites, to identify recommendations for safer sites and techniques of administering deltoid IMIs. All the authors strictly adhered to a well-developed registered review protocol throughout the study and followed the risk of bias in systematic reviews (ROBIS) guidance tool. The proposed sites and landmark data were tabulated, and each site was analyzed based on the underlying neurovascular structures. Data were depicted by self-generated images.The initial search identified 174 articles. After applying the inclusion and exclusion criteria, 57 articles were shortlisted. Out of the 39 selected articles, 18 focused on the administration of deltoid IMIs, whereas seven focused on the variations in the underlying neurovascular structures in proximity to the deltoid muscle. The remaining 14 articles were the immunization guides issued by the National Public Health Agencies of the Government of India and abroad, whose data was used for comparison. Twelve deltoid IMI sites and techniques were identified. A site 1-3 fingerbreadths/5 cm below the mid-acromion point (7 studies); mid-deltoid site/densest part of the deltoid (1 study); a site at the middle third of the deltoid muscle (1 study); triangular injection site (1 study). Limitations included the unavailability of free access to complete text in many articles resulting in exclusion. The area around the shoulder joint and up to the lower level of the intertubercular sulcus is highly vascularized by the presence of many anomalous arterial patterns. To avoid injury, a safer site is proposed of 5 fingerbreadths/10 cm below the midpoint of the lateral border of the acromion. The authors received no specific funding for this study except for the journal publication charges.

Acceptance of the Deltoid Muscle Injection of Aripiprazole Long-acting Injectable in the Patients with Schizophrenia.

ObjectiveTo improve poor medication adherence in schizophrenic patients, long-acting injectable (LAI) antipsychotics are used. However, it has not yet become common in Japan. Recently, aripiprazole LAI was approved for alternative injection into the deltoid muscle in addition to the gluteal muscle. The acceptance for the proposal to switch from gluteal to deltoid injections of aripiprazole LAI was investigated.MethodsThe subjects were 32 outpatients with schizophrenia who had continuously received aripiprazole LAI administration into the gluteal muscle for ≥ 6 months. In the patients who had continued deltoid injection for 3 months after switching, the changes in the pain and shame in comparison with gluteal injections were evaluated.ResultsSwitching to the deltoid injection was chosen by 17 out of 32 patients. Three months later, 9 patients were still receiving deltoid injections with highly rated satisfaction. The main reasons for switching to deltoid injections included the pain and shame associated with gluteal injections. The main reason for returning to the gluteal injection was the pain experienced from the injection in the deltoid.ConclusionThe option to select the injected area was based on the amount of pain in the deltoid and gluteal sites, leading to the widespread use of aripiprazole LAI.

Best practice for deltoid intramuscular injections in older adults: Study in cadavers

Most injectable vaccines are administered via deltoid intramuscular injection (IMI). Nursing students are taught to perform deltoid IMI in their entry-to-practice education program. However, best practice evidence is lacking regarding specific techniques of deltoid IMI, and students are often taught what their instructor was taught in his/her own entry-to-practice (ETP) program. Nursing textbooks provide instructions and diagrams for how to perform deltoid IMI, but rarely cite underpinning empirical evidence. This study tested the injection techniques of bunching (squeezing) or flattening (stretching) the deltoid muscle before administering IMI using medical school donated cadavers. Flattening technique resulted in over-penetration of deltoid injections more than 85% of the time in these older adults, whereas nearly 80% of deltoid IMI are successful using bunching technique. Body mass index (BMI) and needle length are also crucial considerations when administering deltoid IMI. Nurses, and other health professionals who use deltoid IMI to administer vaccines to older adults, should determine the client’s body mass index to select the appropriate needle length. Based on these results, bunching technique is recommended. Flattening technique is not recommended for older adults with a BMI < 30.

Pharmacokinetics and safety of deltoid or gluteal injection of aripiprazole lauroxil NanoCrystal® Dispersion used for initiation of the long-acting antipsychotic aripiprazole lauroxil.

Background:Aripiprazole lauroxil (AL), a long-acting injectable antipsychotic for the treatment of schizophrenia in adults, can be started with either 21 days of daily oral aripiprazole supplementation or a 1-day initiation regimen consisting of a single injection of a NanoCrystal® Dispersion formulation of AL (ALNCD) and a single dose of 30 mg oral aripiprazole. This phase I study assessed the pharmacokinetics and safety of deltoid versus gluteal ALNCD injections.Methods:Patients with schizophrenia or schizoaffective disorder (N = 47) were randomized 1:1 to receive a single intramuscular dose of ALNCD in the deltoid or gluteal muscle. Plasma samples were collected over 85 days to measure ALNCD concentration by injection site. Relative aripiprazole bioavailability for deltoid versus gluteal injection was assessed based on area under the curve (AUC∞ and AUClast) and maximum concentration (Cmax) values. Adverse events were monitored throughout the study.Results:Plasma aripiprazole concentrations after a single ALNCD injection were comparable between deltoid and gluteal administration. Mean maximum plasma aripiprazole concentrations were 196.1 ng/ml (deltoid) and 175.0 ng/ml (gluteal). Exposure to aripiprazole was similar, with mean AUC∞ values of 6591 day × ng/ml for deltoid and 6437 day × ng/ml for gluteal. Aripiprazole bioavailability was not significantly different between injection sites. ALNCD administration in the deltoid or gluteal muscle was well tolerated, with similar safety profiles at both sites.Conclusion:ALNCD demonstrated similar exposure and safety profiles between the two administration sites, suggesting that ALNCD can be given in either the gluteal or the deltoid muscles as a component of the 1-day initiation regimen for AL.

Procedural and Physical Interventions for Vaccine Injections: Systematic Review of Randomized Controlled Trials and Quasi-Randomized Controlled Trials.

This systematic review evaluated the effectiveness of physical and procedural interventions for reducing pain and related outcomes during vaccination. Databases were searched using a broad search strategy to identify relevant randomized and quasi-randomized controlled trials. Data were extracted according to procedure phase (preprocedure, acute, recovery, and combinations of these) and pooled using established methods. A total of 31 studies were included. Acute infant distress was diminished during intramuscular injection without aspiration (n=313): standardized mean difference (SMD) -0.82 (95% confidence interval [CI]: -1.18, -0.46). Injecting the most painful vaccine last during vaccinations reduced acute infant distress (n=196): SMD -0.69 (95% CI: -0.98, -0.4). Simultaneous injections reduced acute infant distress compared with sequential injections (n=172): SMD -0.56 (95% CI: -0.87, -0.25). There was no benefit of simultaneous injections in children. Less infant distress during the acute and recovery phases combined occurred with vastus lateralis (vs. deltoid) injections (n=185): SMD -0.70 (95% CI: -1.00, -0.41). Skin-to-skin contact in neonates (n=736) reduced acute distress: SMD -0.65 (95% CI: -1.05, -0.25). Holding infants reduced acute distress after removal of the data from 1 methodologically diverse study (n=107): SMD -1.25 (95% CI: -2.05, -0.46). Holding after vaccination (n=417) reduced infant distress during the acute and recovery phases combined: SMD -0.65 (95% CI: -1.08, -0.22). Self-reported fear was reduced for children positioned upright (n=107): SMD -0.39 (95% CI: -0.77, -0.01). Non-nutritive sucking (n=186) reduced acute distress in infants: SMD -1.88 (95% CI: -2.57, -1.18). Manual tactile stimulation did not reduce pain across the lifespan. An external vibrating device and cold reduced pain in children (n=145): SMD -1.23 (95% CI: -1.58, -0.87). There was no benefit of warming the vaccine in adults. Muscle tension was beneficial in selected indices of fainting in adolescents and adults. Interventions with evidence of benefit in select populations include: no aspiration, injecting most painful vaccine last, simultaneous injections, vastus lateralis injection, positioning interventions, non-nutritive sucking, external vibrating device with cold, and muscle tension.

Efficacy and safety of flexibly dosed paliperidone palmitate in Chinese patients with acute schizophrenia: an open-label, single-arm, prospective, interventional study.

This open-label, single-arm, multicenter, 13-week, prospective study explored the efficacy, safety, and tolerability of paliperidone palmitate (150 milligram equivalents [mg eq] [day 1], 100 mg eq [day 8], both deltoid injections; 75–150 mg eq, deltoid/gluteal injection) in Chinese patients with acute schizophrenia (Positive and Negative Syndrome Scale [PANSS] total score ≥70), who previously had unsatisfactory therapeutic effect following oral antipsychotic treatment (without washout period). Primary efficacy endpoint was percentage of patients with ≥30% improvement in the PANSS total score at the end of 13 weeks. Secondary efficacy endpoints included change from baseline to end of week 13 in PANSS total score, PANSS subscale scores, Marder factor scores, Clinical Global Impressions–Severity score, and Personal and Social Performance Scale scores. Overall, 477/610 enrolled patients (full analysis set, 78.2%) completed the study (men: 55.1%; women: 44.9%; mean age: 31.5 years). Total, 443/610 (72.6%, full analysis set) patients achieved primary endpoint (mean [standard deviation] change from baseline: –30.9 [19.51]). All secondary endpoints demonstrated significant improvement at the end of 13 weeks. One death occurred during this acute phase. The most common (>5%) treatment-emergent adverse events were extrapyramidal disorders (8.4%). The efficacy and safety data are consistent with other short-term, placebo-controlled studies of paliperidone palmitate conducted in similar populations.

Influence of skin-to-muscle and muscle-to-bone thickness on depth of needle penetration in adults at the deltoid intramuscular injection site

BackgroundThe objectives of the study were to estimate the following in adults of Indian origin: a) Gender and side differences in the skin-to-muscle (SM) and muscle-to-bone thickness (MB) at the deltoid intramuscular injection site; b) Correlation of SM thickness with the BMI, age and gender; c) The prevalence of under and over-penetration assuming a standard needle length of 25 mm and following prescribed guidelines for IM injection. MethodsThe SM, MB and skin-to-bone (SB) thicknesses were bilaterally estimated in two hundred adult Indian subjects (100 male and 100 female) using an ultrasound probe at a pre-determined point on the upper arms of the subjects. The BMI of each subject was calculated. The unpaired sample ‘t’ test and paired ‘t’ test were used to analyse differences between groups. Pearson's correlation coefficient was used in correlation analysis and suitable linear regression equations were generated. ResultsFemales had a significantly higher SM thickness and lower MB thickness. The SM thickness was significantly greater on the left side, while the SB and MB thickness were significantly greater on the right. Multiple linear regression equations for both the dominant and non-dominant arms had good model fit properties. Under-penetration would have occurred in 2 (1%) subjects while over-penetration would have occurred in 50% of the subjects. ConclusionOver-penetration of deltoid IM injections is likely to be more prevalent as compared to under-penetration. Therefore, the technique of IM injection needs to be modified based on the body type of the individual patient.

Teaching best-evidence: Deltoid intramuscular injection technique

Intramuscular injection of vaccines and medications into the deltoid muscle is a long-established nursing practice. The deltoid muscle is the preferred site for intramuscular injections to adult clients in community settings, as it requires minimal, generally socially-acceptable, exposure of the client’s body, and is easily accessible to the professional administering the injection. Nursing students learning to administer deltoid intramuscular injections raise excellent questions about deltoid intramuscular injection technique, in particular around landmarking technique, the use of bunching or flattening technique, and selection of needle length. Surprisingly little empirical evidence to guide the nurse, or to answer student questions about, administering deltoid intramuscular injections was found in the nursing and allied health literature. This article examines deltoid intramuscular injection practice with particular emphasis on teaching nursing students best practice.

Patients' acceptance of the deltoid application of risperidone long-acting injection

Objective: Recently risperidone long-acting injection (RLAI) was approved for alternative injection into the deltoid muscle in addition to the already established injection into the gluteal muscle. For the first time two different injection locations of a long-acting antipsychotic injection can be offered to patients. Their actual acceptance is of key interest. Experimental procedures: We surveyed 60 patients stabilized on gluteal RLAI therapy in our depot outpatient clinic. Participants were offered the possibility of switching to the alternative deltoid injection in a standardized manner. Prior to switching patients scored the extent of perceived pain and experienced level of shame through the present gluteal injection therapy on a 7-point-scale. Patients choosing to switch were followed up after three months and asked to report on their individual experience. Results: Switching to the deltoid application was chosen by 34 out of 60 patients. Three months later 15 patients were still receiving deltoid injections. The main reason for their staying with the deltoid injection was improved practicability as reported by these patients and 13 out of 15 patients clearly preferred the new location over the gluteal application. The main reason for returning to the gluteal injection was the pain experienced through the injection in the deltoid. Patients' initial decision whether to switch was not correlated with either perceived pain or the experienced level of shame through the preceding gluteal injections. Conclusions: The application of RLAI in the deltoid muscle is viewed as an alternative to the injection in the gluteal muscle by a considerable number of patients. Nevertheless, some patients experience increased injection pain through this application location while others perceive the switch as beneficial in terms of practicability. Therefore offering both injection locations with their respective pros and cons should become standard in the RLAI treatment offered.

A comparative study of paliperidone palmitate and risperidone long-acting injectable therapy in schizophrenia

This open-label, rater-blinded, parallel-group study was designed to evaluate noninferiority of paliperidone palmitate (PP), a once-monthly injectable atypical antipsychotic, to once-biweekly risperidone long-acting injectable (RIS-LAI) in adult Chinese patients with acute schizophrenia. Eligible Chinese adults (N=452) with schizophrenia were randomized (1:1) to either PP (N=229; deltoid injections on day 1 [150 mg eq.] and day 8 [100 mg eq.]; then once-monthly deltoid or gluteal injections, flexibly dosed [50, 100, or 150 mg eq.]), or RIS-LAI (N=223; once-biweekly gluteal injections, flexibly dosed [25, 37.5 or 50 mg]). RIS-LAI-treated patients received oral risperidone supplementation (1-6 mg/day) at initiation and with RIS-LAI dose increases. Mean (SD) Positive and Negative Syndrome Scale (PANSS) total score at baseline was 83.2 (12.44). Mean (SD) change from baseline to endpoint in PANSS total scores (primary efficacy measure) was: -23.6 (16.28) for PP group and -26.9 (15.43) for RIS-LAI group. PP was noninferior to RIS-LAI (least squares mean difference [95% CI]: -2.3 [-5.20; 0.63]; predetermined non-inferiority margin: -5.5). Mean (SD) change from baseline to endpoint in Clinical Global Impression-Severity scale score was: -1.5 (1.24; PP group), -1.7 (1.16; RIS-LAI group) and in Personal and Social Performance Scale scores was: 16.8 (14.76; PP group), 18.6 (13.92; RIS-LAI group). The incidence of treatment-emergent adverse events (TEAEs) was similar between the two groups (73% [PP]; 75% [RIS-LAI]). The most common TEAEs were akathisia, tremor, and insomnia. The study demonstrated the noninferiority of PP (50-150 mg eq., flexibly dosed, without oral paliperidone supplementation) to risperidone-LAI (25-50 mg, flexibly dosed, with oral risperidone supplementation) for the treatment of acute schizophrenia in adult Chinese patients. PP injections were generally tolerable, and no new safety signals were detected in this population.

A double-blind study of paliperidone palmitate and risperidone long-acting injectable in adults with schizophrenia

This 13-week double-blind study was designed to assess noninferiority of the recently approved (in the U.S.) injectable atypical antipsychotic paliperidone palmitate (PP) versus risperidone long-acting injectable (RIS-LAI) in adult patients with schizophrenia. Patients (N=1220) were randomized (1:1) to either a) PP: deltoid injections on day 1 (150 mg eq.), day 8 (100 mg eq.), and once-monthly flexible dosing as deltoid or gluteal injections on day 36 (50 mg eq. or 100 mg eq.) and day 64 (50 mg eq. or 100 mg eq. or 150 mg eq.) or b) RIS-LAI: gluteal injections days 8 and 22 (25mg), days 36, 50 (25 or 37.5mg) and days 64, 78 (25, 37.5 or 50mg). RIS-LAI-treated patients received oral supplementation with RIS 1-6 mg/day (days 1 to 28), and PP-treated patients received oral placebo. The safety analysis set (n=1214) included 58% men, 78% white, with mean (SD) baseline PANSS total score: PP, 84.1 (12.09); and RIS-LAI, 83.6 (11.28). Mean (SD) change from baseline to endpoint in PANSS total score decreased similarly in both groups; PP (-18.6 [15.45]) and RIS-LAI (-17.9 [14.24]). PP treatment was noninferior to RIS-LAI (point estimate [95% CI]: 0.4 [-1.62;2.38], per-protocol analysis set [primary analysis]). The tolerability and safety of PP was generally similar to RIS-LAI with no new safety or tolerability findings.

Risperidone Long‐Acting Injection: Pharmacokinetics Following Administration in Deltoid Versus Gluteal Muscle in Schizophrenic Patients

Long-acting injectable (LAI) risperidone for intramuscular injection into the gluteal muscle every 2 weeks is approved for schizophrenia. The deltoid muscle provides a more accessible injection site and could therefore facilitate patient acceptance of an injectable medication. Two studies in chronic schizophrenic subjects evaluated the pharmacokinetics and tolerability of LAI risperidone administered into the deltoid muscle. The pharmacokinetics following deltoid injection and bioequivalence between deltoid and gluteal administration were assessed in an open-label, single-dose, crossover, fully powered bioavailability study. Tolerability and safety of deltoid LAI risperidone were investigated in an open-label multiple-dose study in subjects who were previously being treated with gluteal injections of LAI risperidone. Patients received 4 sequential intramuscular injections of LAI risperidone, administered every 2 weeks into the deltoid muscle. Deltoid and gluteal injections of LAI risperidone were shown to be bioequivalent at equal doses with respect to peak and total plasma exposure and exhibited dose-proportional pharmacokinetics, independent of injection site. In addition, deltoid injection was safe and well tolerated. Injection of LAI risperidone into the deltoid muscle can be considered an alternative route of administration, because deltoid and gluteal injections are interchangeable in terms of drug exposure, with no additional safety or tolerability issues.

Paliperidone palmitate - review of the efficacy, safety and cost of a new second-generation depot antipsychotic medication

To describe the efficacy, safety and cost of paliperidone palmitate, a depot antipsychotic medication recently approved for the treatment of schizophrenia. A literature search was conducted by querying the websites http://www.pubmed.gov, http://www.fda.gov, http://www.accessdata.fda.gov/scripts/cder/drugsatfda and http://www.clinicaltrials.gov for the search term 'paliperidone palmitate'. Cost information was obtained from the pharmaceutical vendor servicing a local state-operated psychiatric facility. All available reports of studies were identified. Product labelling provided additional information. Descriptions of the principal results and calculation of the number needed to treat (NNT) and number needed to harm (NNH) for relevant dichotomous outcomes were extracted from the study reports and synopses. Additional safety outcomes subject to NNH analysis were obtained from product labelling. Paliperidone palmitate is a newly available depot formulation of paliperidone (the 9-OH metabolite of risperidone). Upon injection into the deltoid or gluteal muscle, the release of the drug starts as early as day 1, reaches maximum plasma concentrations at 13 days and lasts for as long as 126 days. Maximum concentration following deltoid injection is approximately 28% higher compared with injection into the gluteal muscle, and thus paliperidone palmitate requires initiation by two initial deltoid injections spread 1 week apart to achieve therapeutic concentrations rapidly. Subsequent injections are at 4-week intervals. Acute efficacy was evidenced by four short-term double-blind, randomised, placebo-controlled, fixed-dose studies of acutely relapsed adult inpatients who met DSM-IV criteria for schizophrenia. NNT for a 30% or greater decrease in the Positive and Negative Syndrome Scale total score compared with placebo was consistently lower for the higher dose strengths of 156 and 234 mg, suggesting a therapeutic dose-response. Treatment with paliperidone palmitate at doses between 39 and 156 mg significantly delayed the time to recurrence of symptoms of schizophrenia after 24 weeks of maintained symptom stability. The NNT vs. placebo to avoid a recurrence of symptoms was 5 (95% CI 4-7). Overall, paliperidone palmitate was reasonably well tolerated, with low rates of extrapyramidal symptoms or body weight gain; however, these may be more common at higher doses. Injection site reactions occurred at a rate ranging from 4% to 10%, depending on the dose regimen, compared with 2% for the pooled placebo arms. The acquisition cost of a maintenance dose of paliperidone palmitate calculated on a per day basis is similar to that for risperidone microspheres, but about double the cost for oral paliperidone and approximately 19 times the cost of oral generic risperidone. Paliperidone palmitate is efficacious for the acute and maintenance treatment of schizophrenia and is reasonably well tolerated. It offers several advantages over other available second-generation depot antipsychotics: it comes in prefilled syringes in a number of different dosage strengths; it does not require refrigeration; it does not require supplementation with oral antipsychotics; it can be administered once monthly; it can be administered with a very small bore needle; the injection volume is small; the injection site can be either the deltoid or gluteal muscles; it does not require an additional precautionary observation period after the injection. For patients for whom oral risperidone or paliperidone is otherwise effective, paliperidone palmitate offers a guaranteed delivery system that enhances adherence. However, the high acquisition cost of paliperidone palmitate will likely be an important obstacle to its routine use.

Safety and tolerability of deltoid and gluteal injections of paliperidone palmitate in schizophrenia

Paliperidone palmitate is an investigational, injectable atypical antipsychotic. The safety and tolerability of initiating treatment with paliperidone palmitate via deltoid versus gluteal injections given once monthly, and of switching injection sites, in adults with stable schizophrenia were assessed. In this crossover trial, stable outpatients ( N = 252) were randomly assigned 1:1:1 to 3 dose groups (paliperidone palmitate 50, 75, or 100 mg eq.) and 2 treatment sequences (blinded to dose): deltoid muscle (period 1 [13 weeks]) followed by gluteal muscle (period 2 [12 weeks]) or the reverse. The intent-to-treat analysis set had 249 patients: mean age = 43 (SD: 12.8) years; 57% men, 81% white, baseline mean Positive and Negative Syndrome Scale (PANSS) total score = 56 (SD: 11.5). A total of 170 (68%) patients completed the study, with a similar proportion completing each treatment sequence. The incidence of systemic treatment-emergent adverse events (TEAEs) was similar between the 2 injection sites across doses during period 1 (deltoid [D]: 61% to 67%; gluteus [G]: 58% to 65%), and during the last 8 weeks of the 2 study periods (DG: 32% to 45% [period 1], 29% to 42% [period 2]; GD: 31% to 40% [period 1], 30% to 41% [period 2]). During the first treatment week, median plasma paliperidone concentrations were higher with treatment initiation in the deltoid muscle compared with the gluteal muscle. At apparent steady state, there was little difference in plasma paliperidone concentrations between the deltoid and gluteus sites for a given dose. Local tolerability was slightly better with gluteal injections. Patient preference for injection sites differed between geographical regions, e.g. patients from the US preferred deltoid to gluteal sites. The most common (≥ 5% overall) TEAEs were: (period 1) insomnia, anxiety, headache, and agitation; and (period 2) insomnia, psychotic disorder, weight increased, and tachycardia. Paliperidone palmitate treatment was tolerated, irrespective of injection site, and thus could offer the choice of administration into either the deltoid or gluteal muscle to meet patient and physician preference.

Safety, immunogenicity, and efficacy of quadrivalent human papillomavirus (types 6, 11, 16, 18) L1 virus‐like‐particle vaccine in Latin American women

The prevalence of HPV infection in Latin America is among the highest in the world. A quadrivalent (types 6/11/16/18) human papillomavirus L1 virus-like-particle vaccine has been shown to be 95-100% effective in preventing HPV 6/11/16/18-related cervical and genital disease in women naive to vaccine HPV types. A total of 6,004 female subjects aged 9-24 were recruited from Brazil, Mexico, Colombia, Costa Rica, Guatemala and Peru. Subjects were randomized to immunization with intramuscular (deltoid) injections of HPV vaccine or placebo at enrollment (day 1), month 2 and month 6. Among vaccinated subjects in the per-protocol population from Latin America, quadrivalent HPV vaccine was 92.8 and 100% effective in preventing cervical intraepithelial neoplasia and external genital lesions related to vaccine HPV types, respectively. These data support vaccination of adolescents and young adults in the region, which is expected to greatly reduce the burden of cervical and genital cancers, precancers and genital warts.

Iatrogenic Axillary Neuropathy After Intramuscular Injection of the Deltoid Muscle

A previously healthy 26-yr-old male presented for an electrodiagnostic evaluation with complaints of significant right deltoid muscle atrophy and shoulder abduction weakness after receiving an intramuscular (IM) deltoid injection of an antiemetic 4 wk earlier. Electrodiagnostic evaluation confirmed an acute axillary neuropathy. We hypothesize that direct mechanical trauma to the anterior branch of the axillary nerve resulted in axillary mononeuropathy with axonal loss, although chemically induced nerve injury cannot be excluded. Injections in and about the shoulder complex are performed routinely for the purposes of vaccination, IM medication administration, deltoid trigger-point injections, and intra-articular and bursal steroid injections. Although such injections are considered routine office procedures, there is increased risk of neurovascular injury if they are performed incorrectly. The purpose of this brief report is to make practitioners aware of the potential for axillary neuropathy with such procedures, to review the salient anatomy, and to propose a potential guideline for clinical practice to minimize iatrogenic axillary neuropathy.