What medication is used to treat pinworms?

Treatment of Pinworm Infection

The first-line medications for treating pinworm infections are mebendazole 100 mg, albendazole 400 mg, or pyrantel pamoate 11 mg/kg (maximum 1 g), all given as a single oral dose with a repeat dose in 2 weeks to eradicate any newly hatched worms. 1, 2, 3

First-Line Treatment Options

• Mebendazole 100 mg as a single oral dose is highly effective with cure rates of approximately 95% for pinworm (Enterobius vermicularis) infections 2
• Albendazole 400 mg as a single oral dose is an equally effective alternative for pinworm treatment 1, 3
• Pyrantel pamoate at 11 mg/kg (maximum 1 g) is another effective option, particularly preferred in pregnant women 3
• All treatments should be repeated after 2 weeks to address newly hatched worms and prevent reinfection 1, 3

Mechanism of Action

• Mebendazole and albendazole are both adulticidal (kill adult worms) and ovicidal (kill eggs) 3
• Pyrantel pamoate is only adulticidal, which is why the second dose is particularly important with this medication 3

Diagnostic Considerations

• The cellophane tape test is the preferred diagnostic method for pinworm infection 1
• A single test has approximately 50% sensitivity, but performing tests on three different mornings increases sensitivity to about 90% 3
• Stool examination is not recommended as pinworms and eggs are not usually passed in stool 3
• Direct visualization of worms in the perianal area is diagnostic 3

Clinical Presentation

• Nocturnal perianal itching is the most common symptom of pinworm infection 1, 3
• Other symptoms may include irritability, weight loss, diarrhea, and abdominal pain 1
• Female genital tract colonization may occur in girls, causing vaginal discharge 1
• Approximately 30-40% of infected patients are asymptomatic 3

Treatment Considerations for Special Populations

• For pregnant women, pyrantel pamoate is preferred over mebendazole and albendazole 3
• Treatment of all household members should be considered, especially with multiple or repeated symptomatic infections 3, 4

Prevention of Reinfection

• Good personal hygiene practices are essential, including frequent handwashing, especially after bowel movements and before meals 3
• Clipping fingernails, avoiding finger-sucking, nail-biting, and scratching in the anogenital area are important preventive measures 3
• Changing and washing underwear, bedding, and nightclothes regularly can help reduce reinfection 4

Common Pitfalls and Caveats

• Recurrences are common despite effective treatment, likely due to repeated cycles of reinfection (particularly autoinfection) 3
• Treatment failure may occur if not all household members are treated simultaneously 3, 4
• For recurrent infections, prolonged treatment for up to 16 weeks using a "pulse scheme" may be recommended 4
• In cases involving genitourinary complications, combination therapy with two oral agents and topical treatment may be warranted 5

Pinworm infection, while not usually dangerous, is one of the most common helminth infections worldwide, with prevalence rates of up to 30% in children globally and up to 60% in some developing countries 3, 6. With proper medication and hygiene measures, most cases can be successfully treated.