Growth hormone (GH) pens are delivery systems, often pre-filled or reusable, designed for the subcutaneous administration of somatropin. These pens offer a convenient and accurate method for managing prescribed GH therapy. Achieving therapeutic benefits depends on mastering the correct administration technique and strictly following the prescribed schedule and dosage.
Preparation Steps Before Injection
Before preparation, wash hands thoroughly with soap and water. Inspect the medication to confirm it is the correct product and has not exceeded its expiration date. Visually check the GH solution; it should appear clear and colorless. If the solution looks cloudy or contains visible particles, the medication should not be used.
GH is temperature-sensitive, so new cartridges or pens are typically stored in the refrigerator between 36°F and 46°F (2°C and 8°C). Some formulations may be allowed to warm to room temperature before injection, following manufacturer instructions. Once verified, a new, sterile pen needle must be attached for every injection. Secure the needle by pushing or screwing it straight onto the pen until it is firmly in place.
Priming the pen removes air bubbles trapped inside and verifies correct medication flow. To prime, dial up a small dose and hold the pen with the needle pointing up. Pressing the injection button should release a drop of fluid from the needle tip, confirming readiness. If no drop appears, repeat the priming process or replace the needle and re-prime.
After successful priming, set the pen to the exact dosage prescribed by the healthcare provider using the dose selector dial. This mechanism allows for precise adjustments, ensuring the patient receives the correct therapeutic amount. The pen is now assembled and prepared for injection.
Performing the Injection
Selecting and rotating the injection site is foundational to long-term GH therapy, as it helps prevent lipohypertrophy, a localized buildup of fat beneath the skin. Common sites for subcutaneous GH injection are the abdomen (avoiding the navel area), the thighs, the buttocks, and the back of the upper arms. Consistent rotation ensures that the tissue at each site has time to recover, promoting reliable absorption of the medication.
Before the injection, clean the chosen site thoroughly with an alcohol swab to minimize infection risk. Allow the alcohol to completely dry before inserting the needle, as injecting through wet alcohol can cause a burning sensation. For shorter needles, pinching a fold of skin may not be necessary. For longer needles or in individuals with less subcutaneous fat, a gentle pinch ensures the medication is delivered into the fatty layer, not the muscle.
Hold the pen like a dart. Insert the needle quickly and smoothly into the pinched skin fold, typically at a 90-degree angle for most short pen needles. Once the needle is fully inserted, press the delivery button or plunger to begin the injection. Hold the button down until the dose counter returns to zero, indicating the full dose has been dispensed.
Maintain the needle’s position for a specific waiting period after the counter reaches zero. Count slowly for 5 to 10 seconds before withdrawing the needle. This pause prevents medication leakage from the injection site, ensuring the patient receives the entire dose. After the waiting time, pull the needle straight out and apply gentle pressure to the site with a clean cotton ball or gauze, taking care not to rub.
Safe Handling, Storage, and Disposal
Immediately following the injection, remove the used pen needle from the device. Never recap needles, as this causes accidental needlestick injuries. Place the detached needle directly into a designated, puncture-resistant sharps disposal container. When the container is about three-quarters full, seal it and dispose of it according to local regulations.
Storage requirements differ between unused and in-use pens and must be followed strictly to maintain GH potency. All backup cartridges and pens should remain refrigerated until their first use. Once a pen is in use, some brands permit storage at room temperature (below 77°F or 25°C) for a limited time, while others require continuous refrigeration.
If a small amount of medication leaks from the injection site, it is usually not a concern. Continuous leakage may indicate a need to adjust injection technique or site rotation. If a scheduled dose is missed, immediately contact the prescribing physician or pharmacist for guidance based on the treatment plan. Never attempt to double the next dose to compensate for the missed one.