Quick Facts

• Primary Use: Pregnancy prevention (contraception).
• Benefit: Provides an option for contraception without estrogen.

Cerazette is indicated for the prevention of pregnancy in women of reproductive age. This medication is a form of progestogen-only contraception, which provides an alternative for individuals who may not be able to use combined contraceptives containing estrogen.

The clinical use of the medication is to provide a reliable method of birth control. Its primary effect is achieved through regulating the body's reproductive cycle to reduce the likelihood of conception. Cerazette is suitable for use during lactation when other forms of contraception may be restricted, and it may be a suitable option for women who have specific health concerns that prevent them from taking estrogen.

Eligibility Scope

Populations for whom use is allowed (as stated in label):

• Women of reproductive age seeking contraception.
• Women who have medical reasons precluding the use of estrogen-containing contraceptives.

Populations for whom use is contraindicated:

• Patients with known hypersensitivity to desogestrel or excipients.
• Patients with active venous thromboembolic disease (e.g., DVT or pulmonary embolism).
• Patients with severe liver disease (active or history) until liver function returns to normal.
• Patients with known or suspected sex-steroid sensitive malignancies (e.g., breast cancer).
• Women with undiagnosed abnormal vaginal bleeding or known/suspected pregnancy.

Age-related eligibility rules:

• Adults (Reproductive Age): The indicated population for contraception.
• Adolescents: Use in those under 18 years is not established as clinical data on safety and efficacy are not available.

Pregnancy and lactation eligibility status (if explicitly documented):

• Pregnancy: Contraindicated. Intake must be stopped immediately if pregnancy occurs.
• Lactation/Breastfeeding: Permitted. Cerazette may be used while breastfeeding.

Eligibility Classifications (High-Level)

Eligibility severity classification (as defined in official documents):

• Contraindicated (Absolute prohibition for certain conditions).
• Use with caution/Requires close observation (Conditional use for conditions like diabetes, epilepsy, or past thrombosis).

Connection to the overall eligibility profile: Official regulatory documents define eligibility by setting clear boundaries: absolute contraindications prohibit use in women with active vascular events, severe liver impairment, and hormone-dependent cancers. Conversely, the profile explicitly permits use during lactation and for women with estrogen intolerance. The regulatory status categorizes use in adolescents as not established due to a lack of available data.

Interactions with other medicines and products

Official regulatory documents describe how Cerazette's efficacy can be affected by other medicines, or how Cerazette itself may alter the effects of co-administered drugs. The primary concern is the reduction of contraceptive effectiveness due to pharmacokinetic interactions.

Interacting Medicinal Products and Substances

The following categories and specific products are documented as having clinically significant interactions, primarily involving the induction of hepatic enzymes which increases the clearance of the active substance (desogestrel):

Interaction Type	Examples of Interacting Medicines/Products
Enzyme Inducers (Reducing Cerazette Efficacy)	Certain medicines for epilepsy (e.g., primidone, phenytoin, carbamazepine, oxcarbazepine), tuberculosis (rifampicin, rifabutin), HIV/Hepatitis C (ritonavir, nelfinavir), and the herbal product St. John’s Wort.
Altered Effect of Co-administered Drug	Medicines containing ciclosporin (plasma levels may increase) and lamotrigine (plasma levels may decrease).

Interaction-Related Constraints

Specific precautions are mandated when co-administering enzyme-inducing agents. If a medicine that can make Cerazette less effective is taken, a barrier contraceptive method must be used during the co-administration and must be continued for 28 days after stopping the interacting medicine. This restriction is necessary to protect against the risk of contraceptive failure. Additionally, the absorption of the active substance can be reduced by certain materials like medical charcoal, requiring procedural constraints similar to a missed pill if vomiting occurs shortly after tablet intake.

Cerazette contains the progestogen desogestrel, which is an inactive prodrug. Upon absorption, desogestrel undergoes rapid hepatic and intestinal metabolism to its biologically active metabolite, etonogestrel. Etonogestrel functions as an agonist with high affinity for the intracellular progesterone receptor (PR), primarily in the hypothalamus, pituitary gland, ovary, and uterus.

Binding to the PR forms a ligand-receptor complex that translocates to the nucleus, acting as a transcription factor to modulate gene expression. This intracellular mechanism leads to a downstream cascade involving the suppression of hypothalamic-pituitary-ovarian axis signaling. Specifically, etonogestrel exerts an antigonadotropic effect, inhibiting the release of pituitary luteinizing hormone (LH) and follicle-stimulating hormone (FSH). This systemic hormonal modulation prevents follicular development and suppresses the LH surge, which are the biological precursors to ovulation.

An additional physiological consequence is the localized modification of cervical tissue, where etonogestrel increases the viscosity and reduces the volume of cervical mucus. This physical alteration restricts sperm cell motility and access through the cervical canal.

Cerazette is administered orally as a 75 microgram film-coated tablet for continuous, long-term use in pregnancy prevention. Dosing involves taking one tablet daily, adhering to a continuous schedule that involves no tablet-free or placebo days between packs.

To ensure consistent use, the medication must be taken at approximately the same time each day, maintaining an interval of roughly 24 hours between doses. The tablet should be swallowed whole.

Procedural Timing and Administration

The most critical administration constraint is the strict 12-hour threshold for timing. If a tablet is taken 12 hours or more past the usual scheduled time, the standard contraceptive reliability is reduced, and a non-hormonal barrier method is required for the subsequent seven days of tablet-taking.

Initiation typically involves starting the first pack on the first day of the menstrual cycle. The medication is also noted for its suitability during lactation. Furthermore, the administration constraints dictate that if severe vomiting or diarrhea occurs within 3 to 4 hours of intake, the event is managed using the established missed-dose protocol due to potential incomplete absorption.

Mechanism of Action and Efficacy Studies

The active ingredient in Cerazette, desogestrel (75 micrograms), is a synthetic progestogen that is converted to the active metabolite, etonogestrel. Unlike traditional progestogen-only pills (POPs), desogestrel primarily prevents pregnancy by consistently inhibiting ovulation in the majority of cycles, a mechanism similar to combined oral contraceptives (COCs).

Clinical trials have evaluated the efficacy of desogestrel 75 micrograms. In a major randomized, comparative trial, the Pearl Index (a measure of contraceptive failure rate) reported for desogestrel was 0.14 per 100 woman-years (excluding gross non-compliance). The study also noted that desogestrel was significantly more effective at inhibiting ovulation compared to the progestogen levonorgestrel in a traditional POP.

---

Safety and Bleeding Patterns

Clinical research indicates that the frequency and pattern of reported adverse experiences for desogestrel 75 micrograms are comparable to those reported for levonorgestrel 30 micrograms. Common reported side effects include headache, acne, and breast pain.

A significant difference observed in comparative trials relates to bleeding patterns:

Bleeding Pattern Observation	Desogestrel 75 μg Users	Levonorgestrel 30 μg Users
Infrequent Bleeding/Amenorrhoea	Higher incidence observed	Lower incidence observed
Irregular/Frequent Bleeding	Higher incidence observed initially	Consistent pattern

Trial data suggests that with increasing duration of use (up to 12 months), desogestrel users showed a tendency toward less bleeding, with almost 50% experiencing infrequent bleeding or amenorrhoea (absence of bleeding) in later cycles. Changes in bleeding patterns do not necessarily indicate a decrease in contraceptive protection.

Common questions about Cerazette (FAQ)

---

Q: Does Cerazette cause weight gain, or is this a common side effect?

According to the official product information, weight increase is listed as an uncommon side effect. This means it may affect between 1 and 10 in every 1,000 women using the medicine. Other common effects reported include changes in mood, acne, breast tenderness, and menstrual irregularity.

---

Q: Can I use Cerazette if I'm breastfeeding my baby?

Regulatory documents state that Cerazette may be used while breastfeeding. A small amount of the active substance, desogestrel, passes into the breast milk. Regulatory sources indicate that there is no evidence of an effect on the growth or development of infants in studies involving the use of Cerazette during breastfeeding.

---

Q: What happens if I forget to take a Cerazette tablet?

The official product information outlines specific steps recommended for a missed tablet, which depend on how late the dose is. If the delay is less than 12 hours, the product label describes a method involving taking the missed tablet right away and continuing as usual. When a tablet is more than 12 hours late, the official guidance outlines steps to take, which typically include taking the tablet and using additional barrier protection for seven days. It is essential to consult the full patient information leaflet for complete instructions.

---

Q: Does Cerazette protect me against STIs (sexually transmitted infections)?

No, according to the official product information, Cerazette is only a contraceptive (prevents pregnancy). It does not provide any protection against sexually transmitted infections, including HIV/AIDS. Only barrier methods like condoms can help protect against STIs.

---

Q: Will Cerazette stop my periods (menstruation)?

Official information indicates that Cerazette can cause changes to your bleeding pattern. This may include making periods irregular or causing them to stop altogether (amenorrhoea). This is a common and expected effect, and women may experience bleeding more or less frequently, or not at all.

Official Storage and Disposal Requirements

Cerazette (desogestrel 75 microgram tablets) must be stored strictly according to the official product labeling to maintain its stability and effectiveness over the 36-month shelf-life.

Storage Conditions

The medicine should be kept at a controlled temperature between 2 C and 30 C.

It is required to protect the tablets from both light and moisture, meaning they should remain in the original packaging until use. A crucial safety requirement is to store the medicine securely, out of the sight and reach of children and pets.

Disposal Instructions

Regulatory guidance directs the safe disposal of unused or expired medication. The preferred method is to use a drug take-back program or pharmacy-provided disposal service, when available. If a take-back program is not accessible, the medicine should be mixed with an unappealing substance, placed in a sealed bag, and discarded with household trash. Do not flush Cerazette down the toilet or pour it down a drain to prevent environmental release.