Susten Injection (Progesterone)

Introduction About Susten Injection (Progesterone)

Susten Injection (Progesterone) is an injectable form of the natural hormone progesterone. Progesterone plays a key role in regulating the menstrual cycle and supporting the uterine lining (endometrium).

When progesterone levels are too low, cycles can become irregular, bleeding patterns can change, and in fertility treatment, the luteal phase may need extra hormonal support.

This medication is used under a clinician’s guidance, since the right dose and schedule depend a lot on the reason it is being prescribed.

What Susten Injection is commonly prescribed for

Progesterone injections are prescribed for a few different medical situations. The exact approved uses and how they are described can vary by product labeling, so it is best to follow your prescriber’s plan. Commonly discussed uses include:

• Amenorrhea (missed periods) is related to hormonal imbalance, after other causes have been evaluated.
• Abnormal uterine bleeding occurs when bleeding is due to a hormone imbalance rather than conditions that require different treatment.
• Luteal phase support in infertility care, including some assisted reproductive technology (ART) protocols, when a clinician wants steady progesterone support.

It is important not to self-diagnose. Missed periods or abnormal bleeding can happen for many reasons, including pregnancy, thyroid disease, fibroids, polyps, or other conditions that need specific evaluation.

How it works in the body

Progesterone helps stabilize and prepare the uterine lining. In a typical menstrual cycle, progesterone rises after ovulation. If pregnancy does not occur, progesterone levels fall and a period starts.

When progesterone is given as a medication, it can help align the hormonal pattern with the body’s normal pattern, depending on the treatment goal your clinician aims to achieve.

How is it given

Susten Injection is usually given as a deep intramuscular (IM) injection, often into the gluteal muscle. Many progesterone injections are oil-based, so the shot can feel thick and may cause soreness afterward. Some practical points patients often notice:

• Injection site pain, swelling, or a lump can happen.
• Rotating injection sites may reduce irritation.
• A nurse, clinic, or trained caregiver may administer it. If you are taught self-injection, follow sterile technique carefully.

Do not inject it intravenously unless you are specifically instructed by a qualified professional, since progesterone injections are typically intended for IM use.

Available strengths

Strengths can vary by manufacturer and supply. Susten Injection (Progesterone) is often found in strengths such as:

• 25 mg/mL
• 50 mg/mL
• Susten 100 mg Injection (Progesterone)
• Susten 200 mg Injection (Progesterone)
• Susten 8% Vaginal gel (Progesterone)
• Susten 400 mg (Progesterone)

Packaging also varies (single-dose ampoules or multi-dose vials). If you are switching brands, confirm the concentration each time. “mL” matters because the same mg dose can be a different volume depending on the strength.

Dosing and schedule

Your dose is based on your diagnosis, ultrasound or lab monitoring (in fertility care), and how you tolerate progesterone. Some protocols use daily dosing for a set number of days, while others use a schedule tied to cycle timing.

Do not change the dose or timing on your own, especially if it is part of an IVF or embryo transfer plan.

Side effects and safety notes

Common side effects can include:

• Injection site pain, redness, swelling
• Breast tenderness
• Headache
• Bloating
• Sleepiness or dizziness
• Mood changes

Serious side effects are less common but need urgent medical attention, including symptoms of a blood clot (one-sided leg swelling, chest pain, shortness of breath), stroke-like symptoms (sudden weakness, trouble speaking), severe migraine-type headache, or severe allergic reaction.

Tell your clinician if you have a history of blood clots, stroke, certain cancers, liver disease, or unexplained vaginal bleeding. Also, share a full medication list, including supplements, since hormone therapy decisions depend on your overall risk profile.

Substitute options

If Susten Injection (Progesterone) is not available or not the best fit, clinicians may consider other progesterone options, depending on the situation:

Injectable progesterone alternatives

• Generic progesterone injection (often listed as progesterone in oil or progesterone IM)

Vaginal progesterone options (commonly used in fertility care)

• Endometrin (progesterone vaginal insert)
• Crinone (progesterone vaginal gel)
• Other progesterone vaginal suppositories (compounded in some settings)

Oral progesterone

• Prometrium (micronized progesterone) and generic micronized progesterone capsules

These are not interchangeable in a simple way. Absorption, side effects (such as drowsiness), and progesterone level stability can vary by route of administration. Your clinician may choose an option based on tolerability, monitoring results, and your treatment plan.

FAQs

1. How should Susten Injection (Progesterone) be stored?

Storage depends on the manufacturer. Many progesterone injections should be kept at controlled room temperature and protected from excessive heat and light. Do not freeze unless the label says it is safe to do so. Always follow the instructions on the carton or vial.

2. Can I drink alcohol while using Susten Injection (Progesterone)?

Alcohol can worsen dizziness, sleepiness, and mood changes in some people. If you drink, keep it moderate and pay attention to how you feel. For fertility or pregnancy-related care, follow your clinician’s guidance.

3. Does Susten Injection (Progesterone) affect pregnancy tests?

Progesterone itself does not typically cause a false positive pregnancy test. Some fertility medications that contain hCG can, but that is a different hormone. If you are unsure what you received, ask your clinic.

4. What if I miss a scheduled dose in a fertility protocol?

Do not double up unless you are specifically told to. Contact your clinic as soon as possible because timing can matter a lot in luteal support and embryo transfer cycles.

5. Can I travel with Susten Injection (Progesterone)?

Usually yes, but plan ahead. Carry it in original packaging, bring supplies (needles, syringes, alcohol swabs), and keep a copy of the prescription. Avoid leaving it in a hot car.