2023 COURSE OF DRUGS ELABORATIONS OF ANTIHELMINTHIC DRUGS

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ANTIHELMINTHIC DRUGS Anthelminthics are drugs that act locally to expel worms from the GI tract or systemically to eradicate adult helminths or developmental forms that invade organs and tissues. T... REATMENT OF INFECTIONS CAUSED BY NEMATODES Nematodes are long, cylindrical unsegmented worms that are tapered on both ends. Some intestinal nematodes contain a mouth with three lips while others have a mouth with cutting plates. Infection occurs after ingestion of embryonated eggs or tissues of another host that contain larval forms of the nematodes. Some of the nematodes such as filarial worms and guinea worms live in blood, lymphatics and other tissues and are referred to as tissue nematodes. Others are primarily found in the intestinal tract (intestinal nematodes). The hookworms are a group of worms that have a developmental cycle in soil. The larvae penetrate the skin of humans, enter the venules and are carried to the lungs where they enter the alveoli and may sometimes cause pneumonitis. The larvae then migrate up the trachea and are swallowed. In the intestine, they attach to the mucosa and using the cutting plates and a muscular oesophagus, they feed on the host’s blood and tissue fluid. This may result in vague abdominal pain, diarrhea and anaemia. Strongyloides stercolaris infection is acquired from larvae which penetrate the skin. This parasite may exist asymptomatically in the small intestine for many decades. However immunosuppression may lead to widespread tissue invasion or hyperinfection. Pinworms migrate to the anus to lay eggs which are transmitted by fingers or through the air. The eggs are ingested and the adult worm develops in the intestinal tract. The symptoms are perianal pruritus and a restless feeling associated with migration of the female worm through the anus to the perianal skin. Other nematodes such as Ascaris lumbricoides are ingested in egg form but have a migration pattern similar to that of the hookworms. [Show More]

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