<prompt> What of the following is true about plasma tl2-Is same as bioavailabilityIt is directly proportional to clearanceIt is inversely proportional to volume of distributionTl2 remains constant for the drugs eliminated by first order kinetics  <response>: Ans. is d i.e., T 12 remains constant for the drugs eliminated by first order kinetics Ivermectin Ivermectin is an extremely potent semisynthetic derivative of nematodal principal obtained from Streptomyces avermitilis. It is the DOC for single dose treatment of onchocerciasis and strongyloidosis. It is the only oral drug effective against scabies and pediculosis. It acts by glutamate gated Cl- channel which causes tonic paralysis in nematodes. Following table depicts the drugs used for the management of round worm infections.Infection OrganismDrug of ChoiceAlternative DrugsRoundworms nematodes Ascaris lumbricoides roundwormAlbendazoles or pyrantel pamoate or membendazolePiperazineTrichuris trichiura whipwormMebendazole or albendazoleOxantelpyrantel pamoateNecator americanus hookworm; Ancylostoma duodenale hookwormPyrantel pamoate or mebendazole or albendazole Strongyloides stercoralis threadwormIvermectinThiabendazole, albendazoleEnterobius vermicularis pinwormMebendazole or pyrantel pamoateAlbendazole fTrichinella spiralis trichinosisMebendazole, add corticosteroids for severe infectionAlbendazole; add corticosteroids for severe infectionTrichostrongylus speciesPyrantel pamoate or mebendazoleAlbendazoleCutaneous larva migrans creeping eruptionAlbendazole or ivermectinThiabendazole topicalVisceral larva migransAlbendazoleMebendazoleAngiostrongylus contonensisThiabendazoleAlbendazole or mebendazoleWuchereria bancrofti filariasis; Brugia malayi filariasis; tropical eosinophilia; Loa loa IoiasisDeithylcarbamazineIvermectinOnchocerca volvulus onchocerciasisIvermectin Dracunculus medinensis guinea wormMetronidazoleThiabendazole or mebendazoleCapillaria phillippinensis intestinal capillariasisAlbendazoleMebendazole or thiabendazole 