Norditropin is a prescription growth hormone injection used to treat growth failure in children and growth hormone deficiency in adults. It contains somatropin, a lab-made version of the growth hormone your body naturally produces. The medication is FDA-approved for several specific conditions and is given as a daily injection under the skin using a prefilled pen device.
Approved Uses in Children
Norditropin is prescribed for children who aren’t growing at a normal rate due to one of four conditions:
- Growth hormone deficiency (GHD): The child’s pituitary gland doesn’t produce enough growth hormone on its own, leading to short stature and slow growth.
- Turner syndrome: A chromosomal condition affecting girls that causes short stature along with other developmental differences.
- Noonan syndrome: A genetic disorder that can affect height, heart development, and other body systems.
- Small for gestational age (SGA): Children who were born significantly smaller than expected and haven’t caught up in height by age 2 to 4.
In all of these cases, the goal is to help the child reach a more typical adult height. Treatment works only while the growth plates in a child’s bones are still open, which is why Norditropin is not used in children whose growth plates have already closed. Once the bones have fused, additional growth hormone won’t increase height.
Approved Uses in Adults
Adults can be prescribed Norditropin if they have a confirmed growth hormone deficiency. This can develop in two ways: it may carry over from a childhood diagnosis, or it can begin in adulthood due to damage to the pituitary gland from a tumor, surgery, radiation treatment, or other causes.
Growth hormone deficiency in adults doesn’t affect height, but it does affect body composition, energy levels, bone density, and cholesterol. Adults with untreated GHD often have increased body fat (especially around the midsection), reduced muscle mass, lower bone mineral density, and fatigue. Norditropin treatment aims to reverse or improve these changes over time.
How Norditropin Works
Somatropin, the active ingredient in Norditropin, is structurally identical to the growth hormone made by the pituitary gland. When injected, it travels through the bloodstream and stimulates the liver to produce a protein called IGF-1 (insulin-like growth factor 1). IGF-1 is the main signal that tells bones, muscles, and organs to grow.
In children, this process directly drives bone lengthening and overall growth. In adults, it helps maintain healthy muscle mass, supports bone strength, influences how the body stores and burns fat, and plays a role in energy metabolism. The effects aren’t immediate. Children typically see measurable growth over months, and adults notice gradual changes in body composition and energy over a similar timeline.
How It Is Given
Norditropin comes in a prefilled pen called the FlexPro, which is designed for daily self-injection under the skin. Common injection sites include the thigh, abdomen, or upper arm, and rotating the site each day helps prevent skin irritation. Most people inject once daily, typically in the evening to mimic the body’s natural pattern of releasing growth hormone during sleep.
The dose varies significantly depending on the condition being treated. Children with GHD typically receive 0.024 to 0.034 mg per kilogram of body weight per day, given six to seven times a week. Children with Turner syndrome, Noonan syndrome, or SGA receive higher doses, up to 0.066 or 0.067 mg/kg/day, because these conditions require more growth hormone to achieve a meaningful growth response.
For adults, the starting dose is much lower, around 0.2 mg per day regardless of body weight. This is gradually increased every one to two months based on how the person responds and what their blood tests show. The maximum adult dose typically caps at about 0.016 mg/kg/day for weight-based dosing. This slow approach minimizes side effects.
Monitoring During Treatment
Regular blood tests are a standard part of Norditropin therapy. Your doctor will check IGF-1 levels to make sure the dose is producing the right amount of growth factor, adjusted for your age and sex. If IGF-1 runs too high, the dose is reduced; if it’s too low, the dose may be increased.
Blood sugar and thyroid function are also monitored, since growth hormone can affect how your body handles glucose and may unmask or worsen thyroid problems. Children on treatment will have their height and growth velocity tracked at regular clinic visits to assess whether the medication is working.
Common Side Effects
The most frequently reported side effects in adults include joint pain, swelling in the hands or feet due to fluid retention, muscle pain, and tingling or numbness in the skin. These tend to be more common at higher doses and often improve as the body adjusts or when the dose is lowered.
In children, headaches and injection site reactions (redness, soreness, or small bumps) are among the most common complaints. Less commonly, children may develop a limp or hip pain, which can signal a condition where the top of the thigh bone slips at the growth plate. This requires prompt medical attention. Growth hormone therapy can also cause the spine to curve more noticeably in children who already have scoliosis, so spinal checks are part of routine monitoring.
Who Should Not Use Norditropin
Norditropin is not safe for everyone. It should not be used by people with active cancer, since growth hormone can promote cell growth. It’s also contraindicated in people who are critically ill after major surgery, serious trauma, or acute respiratory failure, as studies have shown increased risk of death in these situations when somatropin is given at high doses.
Children with Prader-Willi syndrome face a specific warning: those who are severely obese or have a history of airway obstruction or sleep apnea should not use Norditropin due to the risk of sudden death. People with severe diabetic eye disease (active proliferative or severe non-proliferative retinopathy) and anyone with a known allergy to somatropin or its inactive ingredients are also excluded from treatment.
Storing the FlexPro Pen
Before first use, Norditropin pens must be kept refrigerated between 36°F and 46°F (2°C to 8°C). Don’t place them right next to the cooling element in the fridge, and never freeze them. Once you start using a pen, you have two storage options: keep it in the refrigerator and use it within 4 weeks, or store it at room temperature (no warmer than 77°F or 25°C) and use it within 3 weeks. The room temperature option makes travel and daily use more convenient, though it does shorten the pen’s usable life by one week.