Pronunciation: en-JEN-lah
Generic name: somatrogon-ghla
Dosage form: pre-filled injectable pen for subcutaneous use (24mg/1.2ml, 60mg/1.2ml)
Drug class: Growth hormones

Medically reviewed by Carmen Pope, BPharm. Last updated on Mar 13, 2025.

What is Ngenla?

Ngenla is a long-acting human growth hormone used to treat children aged 3 and older who are not growing because of growth hormone deficiency (GHD). It is given by injection under the skin (subcutaneously) once a week, and older children and caregivers can be taught how to administer it.

Ngenla (somatrogon) gained FDA approval on June 28, 2023 and is manufactured by Pfizer Ireland Pharmaceuticals. There is no generic or biosimilar.

How does Ngenla work?

Ngenla works by binding to growth hormone receptors throughout the body, particularly in the liver, muscles, bones and other tissues. This stimulates the production of a substance called Insulin-Like Growth Factor (IGF-1) that mediates metabolic and other changes to regulate metabolism, stimulate the growth plates in long bones, and enhance growth.

Ngenla has a modified structure that allows one-weekly administration compared with other growth hormone treatments that are given daily. It contains human growth hormone fused with a portion of human chorionic gonadotropin (hCG) to make a larger protein (somatrogon) that stays in the blood stream longer. Somatrogon has a half-life of about 70-80 hours compared to the 3.8-hour half-life of natural growth hormone.

Side effects

The most common side effects of Ngenla are:

• injection site reactions (such as pain, swelling, rash, itching, bleeding)
• common cold
• headache
• fever
• low red blood cells (anemia)
• cough
• vomiting
• decrease in thyroid hormone levels
• stomach (abdominal) pain
• rash
• throat pain.

Serious side effects and warnings

Ngenla may cause the following serious side effects:

• high risk of death in people who have critical illnesses because of heart or stomach surgery, trauma or serious breathing (respiratory) problems
• serious allergic reactions. Get medical help right away if your child has the following symptoms:
  • swelling of the face, lips, mouth, or tongue
  • trouble breathing
  • wheezing
  • severe itching
  • skin rashes, redness, or swelling
  • dizziness or fainting
  • fast heartbeat or pounding in the chest
  • sweating.
• increased risk of growth of cancer or a tumor that is already present, and increased risk of the return of cancer or a tumor in people who were treated with radiation to the brain or head as children and who developed low growth hormone problems. Your child’s healthcare provider will need to monitor your child for a return of cancer or a tumor. Contact your child’s healthcare provider if your child starts to have headaches, or has changes in behavior, changes in vision, or changes in moles, birthmarks, or the color of the skin
• new or worsening high blood sugar (hyperglycemia) or diabetes. Your child’s blood sugar may need to be monitored during treatment with Ngenla
• increase in pressure inside the skull (intracranial hypertension). If your child has headaches, eye problems, nausea or vomiting, contact your child’s healthcare provider
• your child’s body holding too much fluid (fluid retention) such as swelling in the hands and feet, pain in the joints or muscles or nerve problems that cause pain, burning or tingling in the hands, arms, legs and feet. Fluid retention can happen in children during treatment with NGENLA. Tell your child’s healthcare provider if your child has any of these signs or symptoms of fluid retention
• decrease in a hormone called cortisol. Your child’s healthcare provider will do blood tests to check your child’s cortisol levels. Tell your child’s healthcare provider if your child has severe fatigue, dizziness, weakness, vomiting, dehydration, or weight loss
• decrease in thyroid hormone levels. Decreased thyroid hormone levels may affect how well NGENLA works. Your child’s healthcare provider will do blood tests to check your child’s hormone levels
• hip and knee pain or limp (slipped capital femoral epiphysis). Tell your child’s healthcare provider if your child has any of these signs or symptoms
• worsening of curvature of the spine (scoliosis). If your child has scoliosis, your child will need to be checked often for an increase in the curve of the spine
• severe and constant stomach (abdominal) pain. This could be a sign of pancreatitis. Tell your child’s healthcare provider if your child has any new abdominal pain
• loss of fat and tissue weakness in the area of skin you inject. Talk to your child’s healthcare provider about rotating the areas where you inject Ngenla
• high risk of sudden death in children with Prader-Willi syndrome who are severely obese or have breathing problems, including sleep apnea
• increase in phosphorus, alkaline phosphatase and parathyroid hormone levels in the blood. Your child’s healthcare provider will do blood tests to check this.

Related/similar drugs

Before receiving

Your child should not receive Ngenla if they:

• have a critical illness caused by certain types of heart or stomach surgery, trauma, or breathing (respiratory) problems
• are allergic to somatrogon-ghla or any of the ingredients in Ngenla
• have closed bone growth plates (epiphyses)
• have cancer or other tumors
• have certain eye problems caused by diabetes (such as diabetic retinopathy)
• have Prader-Willi syndrome, are severely obese, or have breathing problems including sleep apnea.

Tell your healthcare provider about all the medical conditions your child has, including if your child:

• has had heart or stomach surgery, trauma or serious breathing (respiratory) problems
• has had a history of problems breathing while they slept (sleep apnea)
• has or has had cancer or any tumor
• has diabetes
• is pregnant or plans to become pregnant
• is breastfeeding or plans to breastfeed.

Pregnancy

It is not known if Ngenla will harm your child’s unborn baby. Talk to your child’s healthcare provider if your child is pregnant or plans to become pregnant.

Breastfeeding

It is not known if Ngenla passes into breast milk. You and your child’s healthcare provider should decide if they will receive it while breastfeeding.

How is Ngenla administered?

Read the detailed Instructions for Use that come with Ngenla.

• Ngenla comes in 2 different dosage strengths. Your child’s healthcare provider will prescribe the dose of medicine and the dosage strength that is right for your child.
• Your child’s healthcare provider will show you how to inject Ngenla before it is used for the first time. Do not try to inject Ngenla until you have been shown the right way by your child’s healthcare provider.
• Inject Ngenla exactly as your child’s healthcare provider tells you to.

Ngenla is injected under the skin (subcutaneously) and can be given in the stomach (abdomen), thighs, buttocks, or upper arms. Rotate the site of injection weekly.

• Inject Ngenla 1 time each week, on the same day each week, at any time of the day.
• You may change the day of the week Ngenla is used as long as the last dose was injected 3 or more days before. After the new day of the week has been chosen, continue with the 1 time a week schedule.

Ngenla prefilled pens are for use by 1 person only.

• Do not share your child’s Ngenla prefilled pens and needles with another person, even if the needle has been changed. Your child may give another person an infection or get an infection from them.

Dosing information

The recommended dosage is 0.66 mg/kg based on actual body weight administered once weekly.

• Individualize dosage for each patient based on the growth response.

• If you are switching from daily growth hormone injections, you may start treatment with once-weekly Ngenla on the day following your last daily injection.

• If more than one injection is required to deliver a complete dose, each injection should be administered at a different injection site.

Ngenla pen directions

The Ngenla pen is available in 2 strengths:

• 24 mg/1.2 mL (20 mg/mL) that delivers a dose in 0.2 mg increments
• 60 mg/1.2 mL (50 mg/mL) that delivers a dose in 0.5 mg increments.

Each turn (click) of the dose knob dials 0.2mg or 0.5 mg of medicine, depending on the pen’s strength.

Always use a new sterile needle for each injection. This will decrease the risk of contamination, infection, leakage of medicine, and blocked needles leading to the wrong dose.

Do not shake your pen. Shaking can damage the medicine.

24 mg/1.2 mL Pen

• You can give from 0.2 mg to 12 mg in a single injection with the 24 mg/1.2mL pen.
• If your dose is more than 12 mg, you will need to give more than 1 injection or ask for the higher strength pen.

60 mg/1.2 mL pen

• You can give from 0.5 mg to 30 mg in a single injection with the 60 mg/1.2mL pen.
• If your dose is more than 30 mg, you will need to give more than 1 injection.
• A new pen may contain slightly more than 60 mg of medicine, this is normal.

What happens if I miss a dose?

If your child misses a dose of Ngenla the missed dose should be injected as soon as possible within 3 days after the missed dose. If more than 3 days have passed, skip your child’s missed dose. Inject the next dose on the regularly scheduled day.

What happens if I overdose?

An acute overdosage may lead initially to low blood glucose levels and subsequently to high blood glucose levels. Overdose with growth hormone may cause fluid retention. Long-term overdosage could result in signs and symptoms of gigantism consistent with the effects of excess growth hormone.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while using Ngenla?

Do not share your pen with other people, even if the needle has been changed. You may give other people a serious infection or get a serious infection from them.

The pen is not recommended for use by the blind or visually impaired without the assistance of a person trained in the proper use of the product.

What other drugs will affect Ngenla?

Tell your child’s healthcare provider about all the medicines your child takes, including prescription and over-the-counter medicines, vitamins, and herbal supplements. Medications that may interact with Ngenla include:

• Glucocorticoid treatment
• Cytochrome P450-metabolized drugs (Ngenla may alter their clearance)
• Oral estrogen (larger doses of Ngenla may be required)
• Insulin and/or other antihyperglycemics (a dosage adjustment of these may be required).

This list is not complete. Other drugs may affect Ngenla, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

How should I store Ngenla?

• Do not freeze your pen or expose it to heat.
• Do not use your pen if it has been frozen or stored in direct sunlight.
• Do not use after the expiration date printed on the label has passed or if it has been more than 28 days after first use.

Before you use Ngenla pens for the first time (unused pens):

• Store in the original carton.
• Store the new, unused Ngenla pen in the refrigerator between 36°F to 46°F (2°C to 8°C).
• Unused prefilled pens may be used until the expiration date printed on the pen label, if kept in the refrigerator.

After you use Ngenla pens and there is still medicine left (up to 28 days of use):

• To help you remember when to dispose of (throw away) the pen, write the date of first use on the pen label.
• Store remaining Ngenla in the refrigerator between 36°F to 46°F (2°C to 8°C) and use within 28 days.
• Keep the pen cap on the Ngenla pen when it is not in use.
• Do not store the remaining Ngenla pen with a needle attached.
• Do not use the Ngenla pen if it has been more than 28 days after first use, even if it contains unused medicine.

Keep Ngenla and all medicines out of the reach of children.

Ingredients

Active ingredient: somatrogon-ghla

Inactive ingredients: citric acid monohydrate, histidine, metacresol (as a preservative), poloxamer 188, sodium chloride, sodium citrate, and water for injection.

Available in two different strengths:

• 24 mg/1.2 mL (20 mg/mL) single-patient-use prefilled pen that delivers the dose in 0.2 mg increments
• 60 mg/1.2 mL (50 mg/mL) single-patient-use prefilled pen that delivers the dose in 0.5 mg increments.

The pens are disposable and should be thrown away in a sharps bin once empty. You can give more than 1 dose from the pen.

Manufacturer

Ngenla (somatrogon) is manufactured by Pfizer Ireland Pharmaceuticals, and distributed by Pfizer Labs, a division of Pfizer Inc., one of the world's largest pharmaceutical companies.

Ngenla Biosimilars

Biosimilar and interchangeable products are biological products that are highly similar to and have no clinically meaningful differences from the reference product.

Reference products

These are biological products that have already been approved by the FDA, against which biosimilar products are compared. There is 1 for Ngenla.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer