Intramuscular (IM) drug administration is one of the most frequently used parenteral routes in clinical practice for the delivery of vaccines, antibiotics, analgesics, antipsychotics, hormonal preparations, and other medications that require relatively rapid or sustained systemic absorption. Although the procedure is often regarded as simple, safe IM administration requires the correct integration of pharmacological knowledge with applied anatomy. Appropriate drug selection, dose, formulation, concentration, injection volume, compatibility, and understanding of absorption characteristics must be considered together with selection of the correct muscle, accurate identification of anatomical landmarks, avoidance of major nerves and blood vessels, and selection of a needle of suitable gauge and length. Errors in any of these components may result in inadequate drug delivery, unintended subcutaneous deposition, pain, bleeding, hematoma, nerve injury, tissue damage, or altered therapeutic response. Evidence also indicates that injection-associated pain can be influenced by injection technique, including site selection and local physical measures, emphasizing that the method of administration is an important component of medication safety [1]. Anatomical factors are particularly important because the thickness of subcutaneous tissue and muscle varies according to sex, body habitus, body mass index, and injection site. Systematic reviews have shown that standard needle lengths may not reliably reach muscle in all patients, particularly in individuals with greater skin-to-muscle distance, and that needle choice should therefore be individualized rather than routinely standardized [2,3]. The gluteal region remains an important site for administration of relatively larger-volume preparations; however, correct selection between ventrogluteal and dorsogluteal regions requires adequate understanding of regional anatomy and surrounding neurovascular structures. Cadaveric evidence has demonstrated variations in muscle and subcutaneous tissue thickness at these sites [4]. A recent systematic review and meta-analysis reported lower pain, bleeding, and hematoma with ventrogluteal injections compared with dorsogluteal injections, although evidence regarding serious injuries remains limited [5]. Similarly, uncertainty continues regarding procedural practices such as aspiration, with randomized evidence evaluating whether aspiration during ventrogluteal IM injection offers clinical benefit or influences injection-related pain [6]. Despite the availability of evidence-based recommendations, studies continue to demonstrate gaps between theoretical knowledge and actual clinical practice. Turan et al. reported that only a minority of nurses working in psychiatric clinics preferred the ventrogluteal site, indicating persistent differences between recommended and routinely adopted practices [7]. Among nursing students, structured web-based education and assessment significantly improved knowledge and skill performance related to IM injection administration [8]. Bieri et al. similarly demonstrated that blended and simulation-supported training significantly increased medical students’ confidence and cognitive knowledge concerning IM injections, including knowledge regarding indications and contraindications [9]. Collectively, these studies demonstrate that knowledge and competence in IM administration can be improved through focused educational interventions; however, contemporary research has largely examined individual professional groups, specific injection sites, educational interventions, or isolated technical aspects of IM administration. An important research gap therefore exists in evaluating IM drug administration as an integrated competency combining both pharmacological principles and clinically relevant anatomical knowledge, particularly across participants at different levels of medical training and clinical experience. Few recent studies have simultaneously examined knowledge regarding drug preparation, dose and volume, pharmacological considerations, site selection, anatomical landmarks, needle gauge and length, patient-specific factors, neurovascular safety, and evidence-based injection technique while comparing medical students with practicing healthcare professionals. Identification of such knowledge gaps may help improve undergraduate medical education, skills-based training, and continuing professional development and ultimately promote safer medication administration. Therefore, the present study aims to assess the knowledge of pharmacological and anatomical principles of safe intramuscular drug administration among medical students and healthcare professionals and to identify specific areas of deficiency that may influence safe clinical practice.

Study Design and Setting A descriptive cross-sectional study was conducted by the Department of Pharmacology in collaboration with the Department of Anatomy at the study institution to assess the knowledge of pharmacological and anatomical principles related to safe intramuscular drug administration among medical students and healthcare professionals. The study focused on participants’ knowledge regarding appropriate drug preparation, selection of injection site, anatomical landmarks, needle selection, injection technique, complications, and safety precautions associated with intramuscular drug administration. The study was conducted after obtaining approval from the Institutional Ethics Committee, and participation was voluntary. Written informed consent was obtained from all participants before enrolment in the study. Study Population and Sample Size The study included a total of 175 participants, comprising medical students and healthcare professionals available at the institution during the study period. Medical students from eligible academic years and healthcare professionals involved in clinical patient care and medication administration were invited to participate. Participants were selected using a convenient sampling method based on their availability and willingness to participate. Inclusion Criteria • Medical students enrolled in the institution who had been exposed to basic pharmacology and human anatomy. • Healthcare professionals involved in clinical care or drug administration. • Participants aged 18 years or above. • Participants willing to provide informed consent. • Participants who completed the study questionnaire in full. Exclusion Criteria • First-year medical students who had not yet received adequate teaching regarding pharmacology or intramuscular drug administration. • Students or healthcare professionals who were absent during the period of data collection. • Participants who were unwilling to participate in the study. • Participants who had previously participated in the pilot testing or validation of the questionnaire. • Questionnaires with substantial incomplete or missing responses were excluded from the final analysis. Study Tool Data were collected using a pre-designed, structured, self-administered questionnaire developed after reviewing standard pharmacology, anatomy, and intramuscular drug administration guidelines. The questionnaire consisted of different sections assessing demographic characteristics and knowledge related to both pharmacological and anatomical aspects of safe intramuscular injection. The questionnaire included questions related to: • Basic pharmacological principles of intramuscular drug administration. • Indications and contraindications for the intramuscular route. • Appropriate drug formulations and volumes suitable for IM administration. • Factors influencing drug absorption from the intramuscular site. • Selection of appropriate injection sites. • Identification of anatomical landmarks for deltoid, vastus lateralis, ventrogluteal, and dorsogluteal injections. • Knowledge regarding major nerves and blood vessels at risk during IM injection. • Appropriate needle length and gauge according to injection site and patient characteristics. • Correct angle and technique of needle insertion. • Knowledge regarding aspiration and current recommended practices. • Prevention and recognition of complications such as nerve injury, hematoma, abscess, pain, and accidental intravascular administration. • Patient-specific considerations such as age, body mass index, muscle mass, and subcutaneous tissue thickness. Each correct response was awarded one mark, while incorrect or unanswered responses were awarded zero marks. The total knowledge score was calculated by summing the individual responses. Based on the percentage of the total score obtained, knowledge may be categorized as poor, moderate, or good, according to predetermined cut-off values. Data Collection • Eligible medical students and healthcare professionals were approached during the predefined study period. • The purpose and objectives of the study were explained to all participants. • Written informed consent was obtained before questionnaire administration. • The structured questionnaire was distributed either in printed form or through an approved electronic platform. • Participants were instructed to complete the questionnaire independently without referring to textbooks, online resources, or assistance from others. • Adequate time was provided for completion of the questionnaire. • Completed questionnaires were collected and checked for completeness. • Data were anonymized using participant codes to maintain confidentiality. • The responses were entered into a spreadsheet and subsequently transferred to statistical software for analysis. Statistical Analysis The collected data were entered into Microsoft Excel and analysed using SPSS statistical software version 23.0. Continuous variables were expressed as mean ± standard deviation, while categorical variables were presented as frequency and percentage. Knowledge scores between medical students and healthcare professionals were compared using an independent Student’s t-test or Mann–Whitney U test, depending on data distribution. Associations between categorical variables and level of knowledge were assessed using the Chi-square test or Fisher’s exact test, wherever appropriate. Correlation analysis may be performed to assess the relationship between knowledge scores and variables such as age, academic level, years of professional experience, or previous training. A p-value <0.05 was considered statistically significant

A total of 175 participants, comprising 105 medical students and 70 healthcare professionals, were included in the present study. Knowledge was assessed across four domains: pharmacological principles, anatomical principles, injection technique, and prevention/recognition of complications. The maximum possible overall knowledge score was 29. Table 1. Demographic, Academic and Professional Characteristics of the Study Participants (n=175) Characteristic Category Total (n=175) Medical students (n=105) Healthcare professionals (n=70) Age, years Mean ± SD 25.90 ± 5.99 21.88 ± 1.26 31.94 ± 5.16 Gender Male 77 (44.0%) 47 (44.8%) 30 (42.9%) Female 98 (56.0%) 58 (55.2%) 40 (57.1%) Participant category Medical student 105 (60.0%) 105 (100%) — Healthcare professional 70 (40.0%) — 70 (100%) Academic year* Second year 35 (33.3%) 35 (33.3%) — Third year 35 (33.3%) 35 (33.3%) — Final year 35 (33.3%) 35 (33.3%) — Professional category† Doctor 40 (57.1%) — 40 (57.1%) Nurse 30 (42.9%) — 30 (42.9%) Clinical experience, years† Mean ± SD — — 6.06 ± 4.02 Previous formal IM injection training Yes 117 (66.9%) 58 (55.2%) 59 (84.3%) No 58 (33.1%) 47 (44.8%) 11 (15.7%) Frequency of IM administration Never/rarely 68 (38.9%) 60 (57.1%) 8 (11.4%) Occasionally 60 (34.3%) 35 (33.3%) 25 (35.7%) Frequently 47 (26.9%) 10 (9.5%) 37 (52.9%) *Percentages for academic year are calculated among medical students. †Percentages and clinical experience are calculated among healthcare professionals. Among the 175 participants, 60.0% were medical students and 40.0% were healthcare professionals. The overall mean age was 25.90 ± 5.99 years, with healthcare professionals being older than medical students as expected. Females constituted a slight majority of the study population at 56.0%. Formal training in intramuscular injection had been received by 66.9% of participants, with training exposure substantially higher among healthcare professionals than medical students. More than half of the healthcare professionals reported frequent administration of IM injections, whereas the majority of students reported never or rarely administering them. These characteristics provide adequate variation in educational level, clinical exposure, and previous training for assessing factors associated with IM injection knowledge. Table 2. Knowledge of Pharmacological Principles of Safe Intramuscular Drug Administration Among Study Participants (n=175) Pharmacological knowledge parameter Correct response n (%) Incorrect response n (%) Correct indication for use of the IM route 133 (76.0%) 42 (24.0%) Identification of formulations suitable for IM administration 127 (72.6%) 48 (27.4%) Knowledge of factors affecting IM drug absorption 100 (57.1%) 75 (42.9%) Knowledge of recommended/maximum injection volume 112 (64.0%) 63 (36.0%) Correct drug preparation and dilution principles 90 (51.4%) 85 (48.6%) Knowledge of contraindications to IM administration 103 (58.9%) 72 (41.1%) Effect of patient-related factors on drug absorption 111 (63.4%) 64 (36.6%) Medication-safety precautions before administration 118 (67.4%) 57 (32.6%) Overall pharmacological knowledge score 5.11 ± 1.65 out of 8 — Knowledge of basic indications for the IM route was relatively high, with 76.0% of participants answering correctly. Identification of suitable IM formulations was also satisfactory in 72.6% of respondents. However, only 57.1% correctly identified factors influencing intramuscular drug absorption, indicating incomplete understanding of the pharmacokinetic principles underlying the route. Knowledge regarding preparation and dilution of IM medications was the weakest pharmacological component, with only 51.4% responding correctly. Approximately 59% correctly identified contraindications to IM administration, while 63.4% understood the effect of patient-related characteristics on absorption. The mean pharmacological score of 5.11 ± 1.65 out of 8 indicates an overall moderate level of pharmacological knowledge with important deficiencies in drug preparation and absorption-related concepts. Table 3. Knowledge of Anatomical Principles and Selection of Safe Intramuscular Injection Sites Among Participants (n=175) Anatomical knowledge parameter Correct response n (%) Incorrect response n (%) Correct identification of deltoid injection site 134 (76.6%) 41 (23.4%) Correct identification of vastus lateralis site 135 (77.1%) 40 (22.9%) Correct identification of ventrogluteal site 111 (63.4%) 64 (36.6%) Correct identification of dorsogluteal site 97 (55.4%) 78 (44.6%) Identification of appropriate anatomical landmarks 97 (55.4%) 78 (44.6%) Knowledge regarding risk of sciatic nerve injury 93 (53.1%) 82 (46.9%) Knowledge regarding major blood vessels at risk 98 (56.0%) 77 (44.0%) Identification of preferred safe gluteal injection site 83 (47.4%) 92 (52.6%) Effect of muscle/subcutaneous tissue thickness on site selection 101 (57.7%) 74 (42.3%) Overall anatomical knowledge score 5.42 ± 1.84 out of 9 — Knowledge was highest for identification of the vastus lateralis and deltoid sites, with correct-response rates of 77.1% and 76.6%, respectively. In contrast, only 63.4% correctly identified the ventrogluteal site, suggesting a relevant gap in knowledge of this recommended gluteal injection region. Approximately half of the participants demonstrated adequate knowledge of anatomical landmarks, sciatic nerve risk, and important vascular structures. The lowest correct-response rate was observed for identification of the preferred safe gluteal injection site, at 47.4%. Knowledge concerning variations in muscle and subcutaneous tissue thickness was also limited, with only 57.7% responding correctly. The mean anatomical score of 5.42 ± 1.84 out of 9 therefore demonstrates moderate anatomical knowledge but clinically important deficiencies regarding gluteal anatomy and neurovascular safety. Table 4. Knowledge Regarding Intramuscular Injection Technique, Needle Selection and Prevention of Complications (n=175) Knowledge parameter Correct response n (%) Incorrect response n (%) Injection-technique parameters Correct 90° angle of needle insertion 126 (72.0%) 49 (28.0%) Correct needle-gauge selection 121 (69.1%) 54 (30.9%) Appropriate needle-length selection 106 (60.6%) 69 (39.4%) Adjustment of needle length according to BMI/body habitus 98 (56.0%) 77 (44.0%) Knowledge regarding current evidence on aspiration 76 (43.4%) 99 (56.6%) Knowledge of site-specific maximum injection volume 91 (52.0%) 84 (48.0%) Correct patient positioning and site rotation 93 (53.1%) 82 (46.9%) Mean injection-technique score 4.06 ± 1.51 out of 7 — Complication-prevention parameters Knowledge regarding prevention of nerve injury 133 (76.0%) 42 (24.0%) Prevention of hematoma and bleeding 108 (61.7%) 67 (38.3%) Prevention of injection-site abscess/infection 115 (65.7%) 60 (34.3%) Recognition of accidental intravascular administration 101 (57.7%) 74 (42.3%) Post-injection observation and recognition of complications 100 (57.1%) 75 (42.9%) Mean complication-prevention score 3.18 ± 1.21 out of 5 — Nearly three-fourths of participants correctly identified the recommended 90° insertion angle, and 69.1% demonstrated appropriate knowledge of needle-gauge selection. However, knowledge declined when patient-specific decision-making was assessed, with only 56.0% correctly recognizing the need to adjust needle length according to body habitus. Knowledge regarding aspiration was the weakest procedural parameter, with only 43.4% answering correctly. Awareness of nerve-injury prevention was comparatively high at 76.0%, whereas recognition of accidental intravascular administration and post-injection complications was correct in approximately 57% of participants. The mean technique score was 4.06 ± 1.51 out of 7, while the complication-prevention score was 3.18 ± 1.21 out of 5. These findings suggest that basic procedural concepts were better understood than contemporary evidence-based or patient-specific aspects of IM administration. Table 5. Comparison of Domain-Wise and Overall Knowledge Scores Between Medical Students and Healthcare Professionals Knowledge domain Maximum score Overall Mean ± SD Medical students (n=105) Mean ± SD Healthcare professionals (n=70) Mean ± SD t-value p-value Cohen's d Pharmacological knowledge 8 5.11 ± 1.65 4.66 ± 1.60 5.79 ± 1.48 4.708 <0.001* 0.727 Anatomical knowledge 9 5.42 ± 1.84 4.96 ± 1.86 6.11 ± 1.58 4.263 <0.001* 0.658 Injection-technique knowledge 7 4.06 ± 1.51 3.71 ± 1.52 4.59 ± 1.35 3.881 <0.001* 0.599 Complication-prevention knowledge 5 3.18 ± 1.21 2.99 ± 1.16 3.47 ± 1.24 2.622 0.010* 0.405 Overall knowledge score 29 17.78 ± 4.57 16.32 ± 4.47 19.96 ± 3.80 5.588 <0.001* 0.862 *Independent-samples Student's t-test; p<0.05 considered statistically significant. Cohen's d: approximately 0.2=small, 0.5=moderate, 0.8=large effect. Healthcare professionals demonstrated significantly higher mean scores than medical students across all four knowledge domains. The mean overall knowledge score was 19.96 ± 3.80 among healthcare professionals compared with 16.32 ± 4.47 among medical students, corresponding to approximately 68.8% and 56.3% of the maximum score, respectively. The difference in overall knowledge was highly statistically significant (t=5.588, p<0.001). The largest standardized difference was observed for the overall score, with a Cohen's d of 0.862, indicating a large effect. Moderate effects were observed for pharmacological, anatomical, and injection-technique knowledge, whereas the difference in complication-prevention knowledge showed a smaller-to-moderate effect. These findings suggest that greater clinical exposure among healthcare professionals may be associated with higher knowledge, although substantial knowledge gaps remain even in the professional group. Table 6. Correlation Between Pharmacological, Anatomical, Injection-Technique and Complication-Prevention Knowledge Scores (n=175) Variables correlated Pearson correlation coefficient (r) 95% CI for r p-value Pharmacological vs Anatomical knowledge 0.445 0.318 to 0.557 <0.001* Pharmacological vs Injection-technique knowledge 0.364 0.228 to 0.486 <0.001* Pharmacological vs Complication-prevention knowledge 0.383 0.249 to 0.503 <0.001* Anatomical vs Injection-technique knowledge 0.412 0.281 to 0.528 <0.001* Anatomical vs Complication-prevention knowledge 0.356 0.219 to 0.479 <0.001* Injection-technique vs Complication-prevention knowledge 0.305 0.164 to 0.434 <0.001* *Pearson correlation; p<0.05 considered statistically significant. All four knowledge domains showed statistically significant positive correlations with one another. The strongest relationship was observed between pharmacological and anatomical knowledge (r=0.445, p<0.001), indicating that participants with better pharmacological knowledge tended also to demonstrate better anatomical understanding. Anatomical knowledge was moderately correlated with injection-technique knowledge (r=0.412, p<0.001), supporting the importance of anatomical understanding for correct procedural performance. Pharmacological knowledge also showed significant correlations with both injection-technique and complication-prevention scores. The weakest, although still significant, relationship was between technique and complication-prevention knowledge (r=0.305, p<0.001). Overall, these results suggest that competence in safe IM administration represents an integrated knowledge construct rather than a collection of completely independent pharmacological, anatomical, and procedural skills.   Table 7. Correlation of Participant Characteristics and Clinical Exposure With Knowledge Scores Participant/exposure variable Knowledge variable Sample analysed Statistical test Correlation coefficient p-value Age Overall knowledge score 175 Pearson r 0.398 <0.001* Age Pharmacological score 175 Pearson r 0.364 <0.001* Age Anatomical score 175 Pearson r 0.294 <0.001* Years of clinical experience Overall knowledge score 70 HCPs Pearson r 0.296 0.013* Years of clinical experience Pharmacological score 70 HCPs Pearson r 0.387 0.001* Years of clinical experience Anatomical score 70 HCPs Pearson r 0.126 0.300 Frequency of IM administration† Overall knowledge score 175 Spearman ρ 0.303 <0.001* Frequency of IM administration† Technique score 175 Spearman ρ 0.226 0.003* Frequency of IM administration† Complication-prevention score 175 Spearman ρ 0.110 0.147 *Statistically significant at p<0.05. †Frequency coded ordinally as 0=never/rarely, 1=occasionally and 2=frequently. Age demonstrated a moderate positive association with overall knowledge (r=0.398, p<0.001), while weaker positive relationships were observed with pharmacological and anatomical knowledge. Among healthcare professionals, years of clinical experience showed a significant positive correlation with overall knowledge (r=0.296, p=0.013) and a stronger relationship with pharmacological knowledge (r=0.387, p=0.001). In contrast, clinical experience was not significantly associated with anatomical knowledge (r=0.126, p=0.300), suggesting that experience alone may not ensure retention of anatomical principles. Frequency of IM administration demonstrated a significant positive correlation with overall knowledge (ρ=0.303, p<0.001) and injection-technique knowledge (ρ=0.226, p=0.003). However, frequency of administration was not significantly associated with complication-prevention knowledge (ρ=0.110, p=0.147). These unadjusted correlations suggest that greater age and clinical exposure may contribute to knowledge acquisition but do not uniformly improve every component of safe IM administration.

The present study assessed the knowledge of pharmacological and anatomical principles underlying safe intramuscular (IM) drug administration among 175 medical students and healthcare professionals. Overall, the participants demonstrated a moderate level of knowledge, with a mean total score of 17.78 ± 4.57 out of 29. Although awareness of basic indications, commonly used injection sites and the 90° insertion angle was relatively satisfactory, important deficiencies were observed in drug preparation, factors affecting absorption, identification of the safest gluteal site, neurovascular anatomy, patient-specific needle selection and current evidence regarding aspiration. These findings indicate that IM administration, despite being considered a routine clinical procedure, requires integration of pharmacology, anatomy and procedural competence. Heshmatifar et al. demonstrated that modification of IM injection technique significantly influenced injection-associated pain, emphasizing that apparently minor technical differences can affect patient outcomes [10]. In the present study, pharmacological knowledge was moderate, with a mean score of 5.11 ± 1.65 out of 8. Knowledge regarding indications and suitable formulations was comparatively better, while only 51.4% correctly answered questions concerning drug preparation and dilution and 57.1% understood factors affecting IM absorption. Such deficits may have implications for drug effectiveness and patient safety. Anatomical and anthropometric factors also influence whether medication actually reaches the intended muscle. Hills et al., in an ultrasound-based study of 402 adults, found that a standard 25-mm needle might be inadequate to reach the deltoid muscle in a proportion of individuals and demonstrated significant relationships between skin-to-muscle distance, BMI and arm circumference [11]. Anatomical knowledge was similarly moderate, with a mean score of 5.42 ± 1.84 out of 9. Although more than three-fourths of participants correctly identified the deltoid and vastus lateralis sites, only 47.4% identified the preferred safe gluteal site and approximately half demonstrated adequate understanding of anatomical landmarks and sciatic nerve risk. These findings are clinically important because inaccurate landmark identification may expose patients to neurovascular injury or ineffective drug deposition. Ogston-Tuck emphasized that safe IM administration requires evidence-based decision-making regarding site selection, equipment and injection technique rather than dependence on habitual practice [12]. Mardourian et al. further demonstrated through CT-based assessment that optimal deltoid site and needle length vary according to patient weight and sex, highlighting the importance of individualized anatomical assessment [13]. Knowledge concerning injection technique also showed notable gaps. While 72.0% recognized the correct insertion angle and 69.1% selected the appropriate needle gauge, only 56.0% understood adjustment of needle length according to BMI or body habitus, and just 43.4% correctly answered questions concerning aspiration. These findings suggest that traditional procedural concepts may be better retained than evolving evidence-based recommendations. Kilroy et al., in an evidence-based quality-improvement project, demonstrated the value of structured education, simulation and updated institutional guidance in promoting safer IM injection practice among nurses [14]. Healthcare professionals had significantly higher scores than medical students in pharmacology, anatomy, technique and complication-prevention domains. The overall score was 19.96 ± 3.80 among healthcare professionals compared with 16.32 ± 4.47 among students (p<0.001), with a large standardized effect (Cohen's d=0.862). This difference may reflect greater clinical exposure and repeated application of theoretical knowledge. Nevertheless, the moderate professional scores indicate that experience alone does not guarantee complete evidence-based competence. Recent educational studies support the importance of repeated and interactive training. Gokalp et al. reported significantly greater IM injection knowledge and skill performance following game-based learning among nursing students [15]. Similarly, Jallad and Işık found that immersive virtual-reality simulation significantly improved psychomotor IM injection performance compared with conventional low-fidelity simulation [16]. The positive correlations observed between pharmacological, anatomical and procedural scores suggest that these domains are interrelated components of safe medication administration. Age (r=0.398, p<0.001), clinical experience (r=0.296, p=0.013) and frequency of IM administration (ρ=0.303, p<0.001) were positively associated with overall knowledge. However, experience was not significantly correlated with anatomical knowledge, and injection frequency was not significantly associated with complication-prevention knowledge. This suggests that repetitive clinical exposure without structured updating may reinforce practice without necessarily strengthening the underlying scientific principles. Gülnar et al. demonstrated that mobile-assisted training and counselling significantly increased nurses' ventrogluteal-site knowledge, supporting continuing professional education even among experienced personnel [17]. Uğur et al. likewise reported significantly better IM injection skill performance among nursing students receiving structured simulation-supported training [18]. Recent ultrasound evidence from Southeast Asian adults also reinforces the need for individualized landmark and needle-length selection rather than universal application of standard anatomical assumptions [19].

The study demonstrates a moderate overall level of knowledge regarding safe intramuscular drug administration, with important deficiencies in pharmacological preparation, gluteal anatomy, neurovascular safety, aspiration practices and patient-specific needle selection. Healthcare professionals performed significantly better than medical students; however, clinically relevant knowledge gaps persisted in both groups. The positive relationships between knowledge, clinical experience and IM injection exposure suggest a beneficial role of practical experience, but the absence of significant associations for some anatomical and safety domains indicates that experience alone is insufficient. Greater integration of pharmacology and applied anatomy, supplemented by simulation-based teaching, periodic competency assessment and continuing evidence-based training, may improve the safety and quality of IM drug administration

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