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Fertility · Injection guide

Cetrotide® (cetrorelix acetate)

A prescription medication used during ovarian stimulation in IVF. Cetrotide® delays ovulation so your clinic controls the timing of your cycle. Here is how it works and exactly how to inject it, reviewed by your pharmacist.

Medically reviewed by
Fora Rahmati, RPh, PharmD
Pharmacist & Owner · Reviewed 2026

Quick facts

TypeSubcutaneous injection, lower abdomen
ClassGnRH antagonist (cetrorelix acetate)
StorageRefrigerated 2–8°C, protected from light
Before useOut of the fridge ~30 minutes to reach room temperature

Always follow your clinic's instructions for dose and timing.

What it is

What is Cetrotide®?

Cetrotide® (cetrorelix acetate) blocks the natural hormone GnRH. Normally, GnRH makes the pituitary gland release luteinizing hormone (LH) and follicle-stimulating hormone (FSH), the hormones that control ovulation.

By stopping GnRH from attaching to its receptors, Cetrotide® temporarily lowers LH and FSH and prevents the natural LH surge that would trigger ovulation. Delaying ovulation gives your doctor more control during fertility treatments like IVF.

Normally

  • GnRH
  • Pituitary releases LH & FSH
  • LH surge
  • Ovulation

On Cetrotide®

  • GnRH receptors blocked
  • LH & FSH stay low
  • LH surge delayed
  • Your clinic sets the timing

Before you begin

Everything you need, on a clean surface

One vial of Cetrotide® powder
One pre-filled syringe with sterile water (diluent)
One yellow-marked needle, for mixing
One gray-marked needle, for the injection
Two alcohol swabs

Storage: always refrigerated between 2–8°C (36–46°F), never frozen, protected from light. Take it out about 30 minutes before injecting so it reaches room temperature.

Labeled diagram of the Cetrotide kit: cover, connection tip, pre-filled syringe, back stopper, plunger, mixing needle and injection needle
Your Cetrotide® kit, labeled — this is what comes home from our pharmacy.

How to inject Cetrotide®, step by step

Six steps, three phases: prep, mix, inject. Your pharmacist walks you through all of it in person or on the phone whenever you need.

  1. 1

    Prep

    Before you begin

    Wash your hands thoroughly with soap and water and lay out your supplies on a clean, flat surface. Take the medication out of the refrigerator about 30 minutes before use so it reaches room temperature. The injection goes into the lower abdomen, at least one inch away from the belly button; use a different spot each day to reduce irritation.

  2. 2

    Mix

    Prepare the solution

    Remove the protective caps from the vial and syringe. Clean the rubber top of the vial with an alcohol swab and let it dry. Attach the yellow-marked needle, inject the sterile water into the vial, and gently swirl until the solution is completely clear. Keep the needle in the vial and withdraw the full dose.

    Pharmacist tip: Swirl, don’t shake. Shaking creates bubbles and can damage the medication.

  3. 3

    Mix

    Switch needles and remove air

    Carefully remove the yellow needle and attach the gray-marked injection needle. Hold the syringe upright, flick it gently so air bubbles rise, and push the plunger slightly until a small drop appears at the needle tip.

  4. 4

    Inject

    Choose and clean the site

    Pick a spot on your lower abdomen at least one inch from the belly button, a different one than yesterday. Clean the area with an alcohol swab and let it dry.

    Pharmacist tip: Rotating sites daily keeps skin irritation down.

  5. 5

    Inject

    Give the injection

    Remove the cap from the gray needle and hold the syringe like a pencil. Gently pinch the skin to create a small fold, insert the needle at a 90° angle, and slowly press the plunger all the way down. Keep the needle in place for about 5 seconds so the full dose is delivered, then withdraw at the same angle and release the skin.

  6. 6

    After

    After the injection

    Apply gentle pressure with a clean swab until any bleeding stops. Discard the syringe and both needles immediately in a sharps container. Never reuse needles or syringes.

Watch it done

Prefer to see it before you try it?

Watch the instructional video on preparing and administering the Cetrotide® injection, or call and our pharmacist will walk you through your first dose.

Five illustrated steps of the Cetrotide injection: assembling the syringe, mixing, removing air, choosing the abdomen site, injecting

What to expect

Side effects to know about

Common, usually mild

  • Short-lasting reactions at the injection site: redness, itching, or swelling
  • Nausea
  • Headache

Rare, but serious

  • Severe allergic reactions, including anaphylaxis, can occur even with the first dose
  • Women with a history of severe allergic conditions should not use this medication
  • Your doctor will review the risks and benefits with you before treatment

Common questions

Cetrotide® FAQ

Something not covered here? Call (905) 235 8820 and a pharmacist will walk you through it.

How should I dispose of used needles and vials?

Place needles and vials in an FDA-cleared sharps disposal container right away. If you don’t have one, use a heavy-duty plastic container with a tight-fitting, puncture-resistant lid: stable, leak-resistant, and clearly labeled as hazardous waste. Never throw loose needles into household trash.

What should I do if I use too much Cetrotide®?

Contact your doctor immediately. They will decide whether your ovarian stimulation procedure needs to be adjusted.

Can I still use Cetrotide® if it was left in a hot or cold car?

No. Cetrotide® must always be stored in the refrigerator between 2–8°C (36–46°F) and protected from light. If it has been exposed to extreme heat or cold, do not use it.

What should I know before starting Cetrotide®?

Your doctor will confirm that you are not pregnant before beginning treatment. Cetrotide® should not be used if you are pregnant or breastfeeding, since its effects on nursing mothers and infants are not known.

Cetrotide® in your protocol?

We dispense it the same day your clinic sends the prescription, deliver across the GTA, and counsel you through your first injection.