What is the first-line treatment for enterobiasis (pinworms)?

First-Line Treatment for Pinworms (Enterobiasis)

Mebendazole 100 mg as a single dose is the first-line treatment for pinworm infection (enterobiasis), with a repeat dose recommended after two weeks to prevent reinfection. 1, 2

Treatment Options and Efficacy

First-Line Medications:

• Mebendazole: 100 mg as a single dose, repeated after 2 weeks 1, 2
  • FDA-approved specifically for Enterobius vermicularis
  • Efficacy rate: approximately 95% cure rate 1
  • Both adulticidal and ovicidal activity 2

Alternative First-Line Options:

• Albendazole: 400 mg as a single dose, repeated after 2 weeks 3, 2

  • Similar efficacy to mebendazole
  • Both adulticidal and ovicidal activity 2

• Pyrantel pamoate: 11 mg/kg (maximum 1 g) as a single dose, repeated after 2 weeks 2

  • Only adulticidal (not ovicidal) 2
  • Preferred option during pregnancy 3, 2

Treatment Algorithm

1. Initial treatment: Administer mebendazole 100 mg as a single dose
2. Repeat treatment: Give a second dose after 2 weeks to kill newly hatched worms
3. Household treatment: Consider treating all household members simultaneously, especially with multiple or repeated infections 2
4. Special populations:
   • Pregnant women: Use pyrantel pamoate instead of mebendazole or albendazole 3, 2
   • Treatment failures: Consider alternative medication or extended treatment course

Important Considerations

Diagnosis

• The cellophane tape test is the gold standard for diagnosis 3
  • Single test sensitivity: ~50%
  • Three consecutive morning tests: ~90% sensitivity
• Stool examination is not recommended as pinworms and eggs are not usually passed in stool 2

Prevention of Reinfection

• Implement strict hygiene measures:
  • Frequent handwashing, especially after using the toilet and before eating 3
  • Regular changing and washing of bedding and underwear
  • Keeping fingernails short and clean
  • Avoiding nail-biting and finger-sucking 2

Common Pitfalls

1. Failure to treat household contacts: Reinfection is common if all household members are not treated simultaneously 2
2. Inadequate follow-up: A second dose after 2 weeks is crucial for complete eradication 2
3. Overlooking hygiene measures: Treatment alone without addressing hygiene practices often leads to reinfection 3, 2
4. Misdiagnosis: Relying solely on stool examination rather than the cellophane tape test can lead to false negatives 3

For recurrent infections that don't respond to standard treatment, extended "pulse therapy" for up to 16 weeks may be necessary 4, or consideration of alternative agents like ivermectin (200 μg/kg) for resistant cases 3, 5.