What can i do?! my 4 year old has pinworms?

Pinworm: The medications used for treatment are mebendazole, pyrantel pamoate, and albendazole. All 3of these drugs are to be given in 1 dose at first and then another single dose 2 weeks later. Pyrantel pamoate is available without prescription. The second dose is to prevent re-infection by adult worms that hatch from any eggs not killed by the first treatment (since the medicine doesnt kill eggs).