What it does
Nonoxynol is a chemical used as a spermicide to prevent pregnancy.
Commonly used for: prevention of pregnancy (contraception)
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Source: Pharmacy and Poisons Board · fetched 2026-01-28 22:10:08 · updated 2026-03-23 04:55:19
About this medicine
Nonoxynol is a chemical used as a spermicide to prevent pregnancy.
What it treats
- prevention of pregnancy (contraception)
How it works
Nonoxynol works by killing sperm, which helps to prevent fertilization of an egg.
Who it's for
This product is for women who want to prevent pregnancy during sexual intercourse.
AI-assisted summary grounded in BNF data - general information only, not medical advice. Always confirm with your pharmacist or doctor.
Clinical monograph: nonoxynol
Nonoxynol is a non-ionic surfactant and spermicide that acts by disrupting the cell membranes of sperm, thereby inhibiting fertilization. It is primarily used in contraceptive products and may also have applications in preventing sexually transmitted infections (STIs). However, its effectiveness as an STI preventive measure has been questioned.
Indications
- Contraception
- Spermicide in barrier methods
- Potential adjunct in STI prevention
Dosage
Children: Nonoxynol is not generally recommended for use in children or adolescents; consult specific guidelines for any pediatric considerations.
Adults: Refer to product-specific guidelines for application methods and frequency as it varies by formulation.
Mechanism of action
Nonoxynol exerts its contraceptive effect by disrupting the membrane integrity of sperm cells, leading to sperm immobilization and death. It also modifies the vaginal environment, which can further inhibit sperm motility and penetration.
Pharmacodynamics
Nonoxynol's primary action is local, affecting the sperm and vaginal tissues upon application. The surfactant properties allow it to lower surface tension, enhancing its ability to disrupt cellular membranes. Its effectiveness can be influenced by the formulation and concentration used.
Pharmacokinetics
Nonoxynol is poorly absorbed systemically when applied topically. Its local effects are primarily confined to the site of application, with minimal systemic exposure expected. The duration of action is limited to the time of application, necessitating reapplication as directed for continued efficacy.
Contra-indications
- Hypersensitivity to nonoxynol or any of its components
- Use in individuals with known irritations or lesions in the genital area
Adverse effects
- Local irritation
- Burning sensation
- Allergic reactions
- Increased risk of urinary tract infections
Precautions
- Use with caution in individuals with sensitive skin
- May reduce the effectiveness of certain barrier contraceptives
- Not recommended for use with vaginal douches or other vaginal products
Pregnancy
Nonoxynol is categorized as a spermicide and is not expected to harm an unborn child when used as directed. However, it is advisable to consult a healthcare professional before use during pregnancy.
Breast-feeding
Nonoxynol is generally considered safe for use while breastfeeding, but consultation with a healthcare provider is recommended.
Storage
Store at room temperature, away from direct sunlight and moisture. Keep out of reach of children.
Formulations
- Spermicidal gel
- Spermicidal foam
- Spermicidal film
- Spermicidal cream
AI-synthesized from BNF references - general information only, not a substitute for professional medical advice or the current BNF. Verify doses with a pharmacist.
This drug in other countries
The same active ingredient registered across other registries we cover - including different brands.