How do I order a separate pen injector for an insulin (or other injectable medication) cartridge?

How to Order a Separate Pen Injector for a Medication Cartridge

Insulin pen devices and pen needles are manufactured and distributed as separate products—you must write a separate prescription for pen needles, as they do not come with the pen injector device. 1

Understanding the Prescription Requirements

The most common prescribing error is assuming the pen comes with needles, which will prevent your patient from using their insulin and represents a critical barrier to therapy initiation. 1 When prescribing an insulin pen system, you need two separate orders:

• Order #1: The insulin pen device itself (e.g., FlexTouch, KwikPen, SoloStar)
• Order #2: Compatible pen needles that attach to the pen 1

Specific Needle Specifications to Prescribe

Prescribe 4-mm, 32-gauge pen needles as your first-line choice for all adult patients, including those with obesity. 1 This recommendation is based on evidence showing these needles are safe and effective regardless of BMI and should be inserted perpendicularly at 90 degrees without requiring a skinfold in most adults. 1

Needle Length Options:

• 4-mm needles: First-line for all patients 1
• 5-mm needles: Acceptable alternative, though 4-mm is preferred 1
• 6-mm or longer: Should NOT be prescribed for children due to excessive risk of intramuscular injection 1

Needle Gauge Specifications:

• 32-gauge (or 31-gauge): Recommended for optimal patient comfort and acceptance 1
• Thin-walled or extra-thin-walled technology: Preferred as they provide better insulin flow while maintaining a narrow gauge 1

Special Population Considerations

Pediatric Patients:

• Children and adolescents should use 4-mm needles when possible 1
• Very young children (≤6 years) must use 4-mm needles with a lifted skinfold and perpendicular insertion 1
• If using 5-mm or longer needles in children, always inject with a lifted skinfold 1

Very Thin Adults:

• Adults with BMI <19 should use 4-mm needles with a lifted skinfold and perpendicular insertion 1

Quantity to Prescribe

Consider prescribing needles based on the patient's injection frequency:

• One needle per injection (needles must be used only once and discarded) 1
• For a patient injecting 4 times daily: prescribe approximately 120-150 needles per month
• Account for priming doses when calculating quantity 1

Critical Patient Education Points to Provide

When prescribing pen needles, ensure patients understand:

• Never reuse needles: They are no longer sterile after a single use 1
• Remove needles immediately after injection: Do not leave attached to the pen, as air or contaminants can enter the cartridge or medication can leak out 2
• Prime the pen before each injection: Ensure at least a drop of insulin appears at the needle tip to verify free flow 2
• Count to 10 before withdrawing: After fully depressing the injection button, wait 10 seconds before removing the needle to ensure complete dose delivery 2, 1
• Never share pens or needles: Even with a new needle, this can transmit blood-borne infections 1

Common Prescribing Pitfalls to Avoid

• Failing to prescribe needles separately: This is the single most common error that prevents patients from initiating therapy 1
• Prescribing needles longer than 6 mm for children: Creates excessive risk of intramuscular injection 1
• Not specifying needle gauge and length: Generic "pen needle" prescriptions may result in suboptimal needle selection 1
• Inadequate quantity: Ensure you prescribe enough needles for the patient's injection frequency, remembering that one needle = one injection 1

Compatibility Verification

Ensure the pen needles are ISO-certified compatible with the specific insulin pen device being prescribed. 2 Standard pen needles attach to most modern insulin pens, but verify compatibility with the manufacturer's specifications for the specific pen device. 1