Why 21G × 1.5" with Regular Bevel for Deep IM Injections and Viscous Medications

The 21-gauge needle (0.8mm outer diameter) provides the larger bore necessary for viscous medications, oil-based hormones, thick antibiotic suspensions, and blood draws where adequate flow rate is essential—the wider lumen significantly reduces injection time and pressure required compared to smaller gauges, preventing medication damage from excessive force while reducing clinician hand fatigue during administration. The 1.5-inch (38mm) length ensures proper penetration into deep muscle tissue in adult patients, particularly in the ventrogluteal and dorsogluteal sites where adequate needle length is critical to reach muscle beyond subcutaneous fat layers—essential for medications requiring intramuscular absorption, vaccines specified for IM route, and procedures where subcutaneous deposition would compromise efficacy or cause adverse reactions. The regular bevel (standard 12-15 degree angle) with Terumo's triple-sharpened technology provides smooth tissue penetration despite the larger diameter, while the precision-manufactured stainless steel cannula maintains sharpness throughout the injection procedure even with viscous substances that can dull lesser-quality needles.

Key Features & Benefits

Key Features:

• 21-gauge (21G) needle with 0.8mm outer diameter for viscous medications
• 1.5-inch (38mm) length for deep intramuscular injections
• Regular bevel with precision-sharpened tip for controlled penetration
• Triple-sharpened bevel technology despite larger diameter
• High-quality stainless steel cannula for durability and sharpness retention
• Color-coded hub (typically green for 21G per ISO standards)
• Transparent or translucent hub for blood flashback visualization
• Compatible with both Luer Lock and Luer Slip syringes
• Thin-wall construction for optimized flow (product dependent)
• Sterile, individually packaged in rigid protective shields
• Box of 100 needles for clinical inventory management
• Latex-free construction for allergy safety
• Manufactured by Terumo (trusted global medical device company)
• Meets ISO and international quality standards
• Single-use, disposable design

Benefits:

• Larger bore accommodates viscous medications without excessive force
• Extended length ensures deep muscle penetration in adults
• Faster flow rate reduces injection and aspiration time
• Sharp bevel maintains smooth penetration despite larger diameter
• Appropriate for blood draws with good flow
• Compatible with multiple syringe types
• Color-coded hub enables quick gauge identification
• Clear hub allows blood return visualization
• Sterile packaging ensures infection control
• Latex-free protects sensitive patients and staff
• Reliable Terumo quality with consistent sharpness
• Cost-effective bulk packaging

Clinical Applications

Terumo 21G × 1.5" hypodermic needles are appropriate for:

✓ Deep intramuscular injections in ventrogluteal site ✓ Deep intramuscular injections in dorsogluteal site ✓ Intramuscular injections in obese patients requiring adequate depth ✓ Viscous medication administration (oil-based hormones, thick suspensions) ✓ Long-acting antipsychotic injections (haloperidol decanoate, paliperidone palmitate) ✓ Testosterone and other hormone replacement therapy (oil-based) ✓ Vitamin B12 injections (cyanocobalamin in oil) ✓ Penicillin benzathine and other thick antibiotic suspensions ✓ Immunoglobulin IM administration ✓ Blood sample collection from veins ✓ Venipuncture for laboratory specimens ✓ Fluid aspiration from joints, cysts, or abscesses ✓ Z-track injection technique for irritating medications ✓ Emergency medication administration requiring rapid delivery ✓ Vaccine administration when IM route specified (influenza, hepatitis) ✓ Mixing and drawing medications from vials ✓ Medical and veterinary applications requiring deep injection

Usage & Application

Pre-Use Preparation:

1. Verify clinical indication:
   • Confirm medication order, dose, route, patient identity
   • Check patient allergies
   • Verify 21G × 1.5" appropriate for medication viscosity and patient anatomy
2. Assess gauge-length appropriateness:
   • 21G advantages:
     • Accommodates viscous medications
     • Faster flow rate for injections and blood draws
     • Adequate for deep IM injections in adults
   • 21G considerations:
     • Larger diameter causes more discomfort than fine gauges
     • More tissue trauma than 23G-25G
     • Not necessary for non-viscous medications
   • 1.5" length appropriate for:
     • Deep IM sites (ventrogluteal, dorsogluteal)
     • Obese patients requiring depth to reach muscle
     • Adults with adequate muscle mass
   • 1.5" may be excessive for:
     • Thin/cachectic patients (shorter needle appropriate)
     • Deltoid injections in average adults (1" typically adequate)
     • Pediatric patients (assess carefully, often need shorter)
3. Gather supplies:
   • Terumo 21G × 1.5" needle
   • Appropriate syringe (3-5 mL common for IM injections)
   • Medication
   • Alcohol swabs
   • Clean gloves
   • Gauze pads
   • Adhesive bandage
   • Sharps container
4. Hand hygiene and glove up
5. Inspect needle package:
   • Check sterile shield integrity
   • Verify expiration date
   • Discard if compromised

Attaching Needle to Syringe:

For Luer Lock:

• Align threads, twist clockwise until secure
• Verify tight connection

For Luer Slip:

• Push straight onto tip with firm pressure
• Ensure fully seated

Drawing Medication:

1. Viscous medications:
   • 21G ideal for thick medications (oil-based, suspensions)
   • Draw slowly to prevent air bubbles
   • May need to warm oil-based medications to room temperature (easier flow)
2. From vials:
   • Clean rubber stopper
   • Inject air equal to dose
   • Invert, withdraw medication
   • Remove air bubbles
3. From ampules:
   • Break ampule
   • Draw medication
   • Replace needle before injection (prevents glass particles, ensures sharp needle)

Intramuscular Injection Technique:

Site Selection for 1.5" Needle:

Best sites:

• Ventrogluteal (preferred): Hip area, large muscle, fewer nerves/vessels
• Dorsogluteal: Buttock, avoid sciatic nerve
• Vastus lateralis: Thigh, good for self-administration

Avoid for 1.5" unless patient very obese:

• Deltoid: 1" needle typically adequate; 1.5" may be too long

Ventrogluteal Site (Preferred for Deep IM):

1. Position patient:
   • Side-lying or standing
   • Expose hip area
2. Locate site:
   • Place heel of hand on greater trochanter
   • Point index finger toward anterior superior iliac spine
   • Spread middle finger toward iliac crest
   • Injection site is triangle formed between fingers
   • Large, safe muscle with few nerves
3. Prepare site:
   • Clean with alcohol in circular motion
   • Allow to dry 30 seconds
4. Insert needle:
   • Stretch skin taut (do NOT pinch for IM)
   • Hold syringe like dart
   • Insert at 90-degree angle with quick, smooth motion
   • Insert to full 1.5" depth (to hub or near-hub)
   • This ensures medication deposited in muscle, not subcutaneous tissue
5. Aspirate (per protocol):
   • Pull back on plunger slightly
   • If blood appears: Withdraw needle, discard syringe, prepare new injection
   • If no blood: Proceed with injection
   • Note: Current guidelines vary—some vaccines no longer require aspiration
6. Inject medication:
   • Push plunger slowly and steadily
   • Viscous medications: use firm, consistent pressure
   • Typical rate: 1 mL per 10 seconds
7. Withdraw needle:
   • Pull straight out quickly at 90-degree angle
   • Immediately cover with gauze
8. Massage or not:
   • DO massage: Most IM injections (promotes absorption)
   • DO NOT massage: Z-track technique, certain medications (check drug info)

Z-Track Technique (for Irritating Medications):

Used for medications that cause tissue irritation or staining:

1. Pull skin and subcutaneous tissue 1-1.5 inches to side
2. Insert needle at 90 degrees
3. Aspirate
4. Inject medication slowly
5. Wait 10 seconds after injection
6. Withdraw needle
7. Release pulled tissue (creates zigzag path, seals medication in muscle)
8. Do NOT massage

Dorsogluteal Site:

Note: Less commonly used due to sciatic nerve proximity; ventrogluteal preferred

1. Position: Prone or side-lying
2. Locate: Upper outer quadrant of buttock
3. Landmarks: Avoid sciatic nerve (runs through lower/inner quadrant)
4. Technique: Same as ventrogluteal (90 degrees, to hub)

Vastus Lateralis Site:

1. Position: Sitting or lying
2. Locate: Middle third of anterior/lateral thigh
3. Divide thigh: Find midpoint between knee and hip, use middle third
4. Technique: 90-degree angle, to hub

Blood Draw Technique:

1. Apply tourniquet 3-4 inches above site
2. Select vein: Palpate, don't just visualize
3. Clean site with alcohol
4. Anchor vein: Pull skin taut below puncture site
5. Insert needle: Bevel up, 15-30 degree angle
6. Advance until flashback in hub
7. Release tourniquet once blood flowing
8. Collect sample
9. Remove needle, apply pressure 2-5 minutes

Fluid Aspiration:

1. Clean site thoroughly
2. Insert needle to appropriate depth
3. Apply negative pressure (pull back plunger)
4. Withdraw fluid slowly into syringe
5. Remove needle and apply pressure
6. Transfer fluid to specimen container if needed

Post-Procedure Care:

1. Do not recap (use one-handed scoop only if necessary)
2. Immediate disposal in sharps container
3. Remove gloves, hand hygiene
4. Document: Medication, dose, route, site, time, patient response
5. Monitor patient for adverse reactions

Troubleshooting:

Needle won't penetrate muscle:

• Ensure quick, dart-like insertion (not slow push)
• Verify needle sharp and new
• May have hit fascia—reposition slightly

Excessive resistance when injecting:

• Normal for very viscous medications
• Use slow, steady pressure (don't force rapidly)
• Warm oil-based medications to room temperature
• Verify needle not occluded

Blood appears during aspiration:

• Withdraw needle immediately
• Apply pressure to site
• Discard syringe and medication
• Prepare new injection, select different site

Medication leaking from injection site:

• May have injected too rapidly
• Needle may not have reached muscle (too shallow)
• Use Z-track technique for next injection
• Insert to full depth (to hub)

Patient reports severe pain:

• May have hit nerve (especially dorsogluteal)
• If sharp, shooting pain down leg: withdraw immediately (sciatic nerve)
• Select different site
• Ventrogluteal has fewer nerve risks

Needle breaks during injection:

• Rare but serious
• Do NOT attempt to retrieve with fingers
• Keep patient still
• Mark site location
• Notify physician immediately
• May require surgical removal

Special Considerations:

Obese patients:

• 1.5" needle appropriate and often necessary
• May need 2" needle for very obese patients (dorsogluteal)
• Assess adipose tissue thickness at site
• Ensure needle reaches muscle (subcutaneous deposition ineffective)

Thin/cachectic patients:

• 1.5" may be too long—risk going through muscle
• Consider shorter needle (1" or 1.25")
• Assess muscle mass at injection site
• Use ventrogluteal (larger muscle than deltoid)

Geriatric patients:

• May have decreased muscle mass
• Assess site carefully
• 1.5" may be appropriate or excessive depending on patient
• Consider muscle mass loss with aging

Pediatric patients:

• Generally do NOT use 1.5" needle in children
• Use shorter needles appropriate for age/size
• Vastus lateralis preferred site for infants/young children
• Assess carefully if adolescent requires 1.5"

Patients on anticoagulation:

• Apply firm pressure for 5-10 minutes after injection
• Monitor for hematoma formation
• IM injections not ideal for anticoagulated patients (prefer SubQ when possible)
• Document anticoagulation status

Viscous medications:

• 21G × 1.5" ideal choice
• Warm oil-based to room temperature (flows easier)
• Use slow, steady injection pressure
• Allow extra time for injection
• Z-track technique may be indicated

Long-acting antipsychotics:

• Requires deep IM for proper absorption
• Ventrogluteal or dorsogluteal preferred
• Use Z-track technique per drug instructions
• Follow specific manufacturer guidelines

Testosterone and hormone therapy:

• Oil-based formulations require larger gauge
• Deep IM essential (ventrogluteal or dorsogluteal)
• Rotate injection sites
• May self-administer—teach proper technique

Blood draws:

• 21G provides good flow rate
• Less hemolysis than smaller gauges for some tests
• Larger bore may cause more discomfort than 22G-23G
• Good for difficult draws where flow needed

Emergency situations:

• 21G appropriate for rapid medication delivery
• Large bore allows fast injection
• Deep IM ensures absorption

Storage:

• Store at room temperature 15-30°C (59-86°F)
• Protect from heat, cold, humidity
• Keep in original packaging
• Store in clean, dry area
• Check expiration dates
• Rotate stock using FIFO
• Do not use expired needles

Disposal:

• Dispose immediately in sharps container
• Never recap with two hands
• Do not separate needle from syringe
• Never place in regular trash
• Seal sharps container when 3/4 full

Infection Control:

• Always use aseptic technique
• Never reuse needles
• Never share between patients
• Discard from damaged packages
• Clean injection sites properly
• New sterile needle for each injection
• Change needles between drawing and injecting

When to Contact Healthcare Provider:

• Persistent pain, redness, swelling at site
• Signs of infection (warmth, drainage, fever)
• Severe bruising or hematoma
• Suspected nerve injury (shooting pain, numbness, weakness)
• Needlestick injury
• Questions about technique or needle selection
• Allergic reaction after injection

Regulatory Compliance:

• Terumo needles meet FDA requirements
• Manufactured in ISO-certified facilities
• Comply with ISO 7864 (sterile hypodermic needles)
• Comply with ISO 9626 (needle dimensions)
• Meet USP standards for sterility
• Color coding follows ISO 6009 (green hub for 21G)
• Latex-free for safety compliance

Technical Specifications

Product Details:

• Manufacturer: Terumo Corporation
• Product Type: Hypodermic needle for injection and aspiration
• Needle Gauge: 21G (0.8mm outer diameter, 0.5mm inner diameter typical)
• Needle Length: 1.5 inches (38mm)
• Bevel Type: Regular bevel (standard 12-15 degree angle)
• Bevel Sharpening: Triple-sharpened for smooth penetration
• Cannula Material: Surgical-grade stainless steel
• Hub Color: Green (per ISO 6009 color coding standard for 21G)
• Hub Material: Medical-grade polypropylene or polycarbonate
• Hub Type: Transparent or translucent for blood flashback visualization
• Connection Type: Universal hub compatible with Luer Lock and Luer Slip syringes
• Wall Type: Regular wall or thin-wall (product dependent)
• Needle Shield: Rigid protective shield for sterility
• Sterility: Sterile, individually packaged
• Sterilization Method: Ethylene oxide (EtO) or gamma radiation
• Latex Content: Latex-free (no natural rubber latex)
• DEHP-Free: Typically yes (verify specific product line)
• Expiration: Typically 5 years from manufacture (check packages)
• Packaging: Box of 100 individually packaged needles
• Intended Use: Intramuscular injection, blood draws, fluid aspiration
• Route: Intramuscular, intravenous access, aspiration
• Patient Population: Adults primarily; adolescents with appropriate assessment
• Regulatory Status: FDA-cleared medical device, Class II
• Standards Compliance:
  • ISO 7864 (sterile hypodermic single-use needles)
  • ISO 9626 (stainless steel needle tubing)
  • ISO 6009 (needle color coding)
• Country of Origin: Varies by facility (check package)