Ovex P is a single-dose tablet used to treat threadworm infections (also called pinworms). Each tablet contains 100 mg of mebendazole, an antiparasitic medicine available from pharmacies in the UK without a prescription. It works for adults and children over the age of 2.
How Threadworm Infections Happen
Threadworms are tiny white worms, roughly 1 cm long, that live in the large intestine. They’re extremely common, especially in children, and spread when microscopic eggs are swallowed. The eggs can survive on surfaces, clothing, bedding, and under fingernails for up to two weeks, which is why they pass so easily between household members.
The most recognizable symptom is intense itching around the anus, particularly at night. That’s when female worms crawl out to lay eggs on the surrounding skin. Scratching transfers eggs to the fingers, and from there to the mouth or to surfaces other people touch. This cycle of reinfection is why hygiene measures matter just as much as the medication itself.
How Ovex P Works
Mebendazole kills threadworms by blocking their ability to absorb glucose and other nutrients from the intestine. Without fuel, the worms starve and die. The process is selective, meaning it targets the worms without interfering with your own nutrient absorption. Most worms are cleared from the body within a few days of taking the tablet.
One important detail: the medication kills adult worms but does not destroy eggs that have already been laid outside the body. That’s why reinfection is so common and why a second dose is often recommended.
Dosage and How to Take It
The standard dose is one tablet, taken as a single dose. This applies to both adults and children over 2. The tablets can be chewed or swallowed whole. Taking the tablet with a meal that contains some fat modestly increases how much of the drug your body absorbs, though no strict food requirement is listed in the prescribing information.
If reinfection occurs, which is common in households with young children, a pharmacist may recommend taking a second tablet two weeks after the first. The two-week gap allows any eggs that were present at the time of the first dose to hatch into adult worms, which the second dose then kills. Treating all household members at the same time is a practical step many pharmacists suggest, even if only one person has symptoms, because threadworm eggs spread so easily between people sharing a home.
Hygiene Steps That Prevent Reinfection
The tablet handles the worms already inside the gut, but eggs scattered around the home can cause a new infection within days. Strict hygiene during and after treatment is the most effective way to break the cycle. The key steps include:
- Handwashing: Wash hands thoroughly with soap and warm water after using the toilet, before eating, and after changing bedding or clothing. Scrub under the fingernails, where eggs tend to lodge.
- Morning showers: Bathing first thing in the morning helps wash away eggs laid overnight around the anus.
- Short fingernails: Keep nails trimmed closely to reduce the space eggs can hide.
- Laundering: Wash bedding, towels, and nightwear at a high temperature on the first morning of treatment. Avoid shaking bedding, which can scatter eggs into the air.
- Underwear changes: Change underwear daily, ideally in the morning.
These measures should continue for at least two weeks after treatment, covering the full lifespan of any remaining eggs in the environment. Encouraging all household members and close contacts like playmates to follow the same practices significantly reduces the chance of the infection bouncing back.
Who Should Not Take Ovex P
Ovex P is not suitable for children under the age of 2. Pregnant women should avoid mebendazole, particularly during the first trimester, as its safety in pregnancy has not been established. If you are breastfeeding, it’s worth discussing the decision with a pharmacist, though only small amounts of the drug pass into breast milk.
People with liver conditions should use caution, since mebendazole is processed through the liver. If you take other medications regularly, check with a pharmacist for potential interactions before taking the tablet.
Possible Side Effects
Because Ovex P is a single-dose treatment and very little of the drug is absorbed into the bloodstream, side effects are uncommon. When they do occur, they tend to be mild: stomach discomfort, bloating, or loose stools. These typically resolve quickly on their own. Allergic reactions are rare but possible, and would show up as a rash, swelling, or difficulty breathing.
For most people, a single tablet clears the infection with no noticeable side effects at all. The bigger challenge is usually preventing reinfection rather than tolerating the medication.