Pinworm Treatment
For pinworm (Enterobius vermicularis) infection, give a single oral dose of albendazole 400 mg or mebendazole 100 mg, and repeat the same dose after 2 weeks; treat all household members simultaneously to prevent reinfection. 1
Drug Selection and Dosing
- First-line options are albendazole 400 mg or mebendazole 100 mg as a single oral dose, both equally effective and safe 1, 2
- The same dose applies to all ages, including children ≥2 years and adults—there is no weight-based adjustment needed 1, 2
- Repeat dosing at 2 weeks is mandatory to eradicate newly hatched worms from eggs that survived the initial treatment 1, 2, 3
- Pyrantel pamoate (11 mg/kg, maximum 1 g) is an alternative but is only adulticidal (does not kill eggs), whereas albendazole and mebendazole are both adulticidal and ovicidal 3, 4
Household and Contact Treatment
- Treat all household members simultaneously, especially when there are multiple or repeated symptomatic infections, because reinfection is extremely common even with effective medication 3, 5
- Sexual partners should also be treated in adult cases to ensure lasting eradication 5
- Asymptomatic household contacts do not require empiric treatment unless there is documented infection or high suspicion of transmission 1
Pregnancy Considerations
- Pyrantel pamoate is preferred during pregnancy over albendazole and mebendazole due to a more established safety profile 3
- Albendazole and mebendazole should generally be avoided in the first trimester, though the risk is considered low based on limited human data 1
Recurrent or Refractory Infections
- Treatment failure is rare; persistent symptoms usually indicate reinfection rather than drug resistance 2
- For recurrent infections despite standard two-dose therapy, consider a prolonged "pulse scheme" for up to 16 weeks with repeated dosing at 2-week intervals 5
- One case report demonstrated successful resolution of recurrent vaginal pinworm infection with three doses of albendazole at 2-week intervals after standard two-dose regimens failed 6
Monitoring and Safety
- No routine monitoring is needed for standard two-dose treatment 1, 2
- If treatment extends beyond 14 days (as in prolonged pulse regimens), monitor liver function and white blood cell counts for hepatotoxicity and leukopenia 7, 2
Hygiene Measures to Prevent Reinfection
- Frequent handwashing, especially after bowel movements and before meals, is critical 3, 5
- Clip fingernails short and discourage nail-biting, finger-sucking, and scratching the perianal area 3, 5
- Wash bed linens and underwear in hot water on the day of treatment to reduce environmental egg contamination 3
- Emphasize supervised body hygiene in young children (ages 4-11 years), who are at highest risk 5
Common Pitfalls
- Failing to treat household members is the most common reason for apparent treatment failure—reinfection from untreated contacts perpetuates the cycle 3, 5
- Skipping the 2-week repeat dose allows newly hatched worms to mature and restart the infection 1, 2
- Relying on stool examination for diagnosis is ineffective because pinworms and eggs are not usually passed in stool; use the cellophane tape test applied to the perianal area in the morning before bathing (sensitivity ~50% for one test, ~90% for three tests on different mornings) 2, 3