PPT_Chapter_38.ppt - Antiparasitic Drugs Chapter 38 Copyright \u00a9 2013 Wolters Kluwer Health | Lippincott Williams Wilkins Parasites \u2022 Parasite \u2013

PPT_Chapter_38.ppt - Antiparasitic Drugs Chapter 38...

This preview shows page 1 out of 39 pages.

Unformatted text preview: Antiparasitic Drugs Chapter 38 Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Parasites • Parasite – organism that lives in or on another organism without contributing to the survival or well-being of the host • Conditions caused by parasites: – Helminthiasis – Malaria – Amebiasis Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Pinworm Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Anthelmintic Drugs Drugs used to treat worms Roundworms, pinworms, whipworms, hookworms, tapeworms Adverse reactions, if they do occur, are usually mild when used in the recommended dosage Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Actions, Uses, and Adverse Reactions of Anthelmintic Drugs • Albendazole – Interferes with the synthesis of the parasite’s microtubules – Used to treat larval forms of pork tapeworm and to treat liver, lung, and peritoneum disease caused by the dog tapeworm Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Actions, Uses, and Adverse Reactions of Anthelmintic Drugs Mebendazole Blocks the uptake of glucose by the worm, which results in a decreased formation of adenosine triphosphate, which is required for survival Drug is used to treat whipworm, pinworm, roundworm, American hookworm, and the common hookworm May cause transient abdominal pain and diarrhea Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Actions, Uses, and Adverse Reactions of Anthelmintic Drugs Ivermectin Binds selectively to glutamate-gated chloride ion channels that eventually results in paralysis and death of the parasite Active against various life-cycle stages of many but not all roundworms Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Actions, Uses, and Adverse Reactions of Anthelmintic Drugs Praziquantel Affects the permeability of the cell membrane to cause a rapid contraction of helminths Pyrantel Activity is probably caused by its ability to paralyze helminths, which causes the worm to release its grip on the intestinal wall and be excreted in the feces Used to treat roundworm and pinworm May experience GI side effects (nausea, vomiting, abdominal cramps, diarrhea) Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Contraindications, Precautions, and Interactions of Anthelmintic Drugs Albendazole Contraindications: known hypersensitivity Caused embryotoxic and teratogenic effects in experimental animals Precautions: hepatic impairment, lactation Interactions: dexamethasone, cimetidine Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Contraindications, Precautions, and Interactions of Anthelmintic Drugs Mebendazole Contraindications: known hypersensitivity Has caused embryotoxic and teratogenic effects in experimental animals Interactions: hydantoins, carbamazepine Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Contraindications, Precautions, and Interactions of Anthelmintic Drugs Ivermectin Contraindications: known hypersensitivity May cause a Mazzotti reaction, which involves skin, systemic, and ophthalmic reactions likely due to an allergic and inflammatory response Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Contraindications, Precautions, and Interactions of Anthelmintic Drugs Praziquantel Contraindications: known hypersensitivity, patients with ocular cysticercosis, patients with a history of epilepsy, signs of potential CNS involvement Interactions: drugs that induce or inhibit cytochrome P450, grapefruit juice Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Contraindications, Precautions, and Interactions of Anthelmintic Drugs Pyrantel Contraindications: known hypersensitivity Precautions: individuals with liver dysfunction, malnutrition, anemia Interactions: piperazine Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Patient Management Issues with Anthelmintic Drugs Diagnosis of a helminth infection is made by examination of the stool for ova or the helminth Patients with massive helminth infections may or may not be acutely ill Gloves should be worn when changing bed linens, emptying bedpans, or obtaining and handling stool specimens Wash hands after removing gloves Patients should wash their hands thoroughly after personal care Each stool is inspected for passage of the helminth Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Patient Management Issues with Anthelmintic Drugs If acutely ill or massive infection, monitor vital signs and measure fluid intake and output Observe patient for adverse drug reactions as well as severe episodes of diarrhea Mebendazole: tablets may be chewed or mixed with food; take with food; obtain a complete blood count before therapy and during therapy Praziquantel: take during meals; tablets should not be chewed; patient should not drive a car or operate machinery on the day that the drug is taken or the following day Pyrantel: take without regard to food or time of day; take with milk or fruit juices Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Educating the Patient and Family About Anthelmintic Drugs Provide complete instruction about household precautions to follow Report symptoms of infection of thrombocytopenia Follow dosage schedule exactly Follow-up stool specimens will be necessary To prevent reinfection and the infection of others in the household, change and launder bed linens and undergarments daily Bathe daily Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Educating the Patient and Family About Anthelmintic Drugs Wash hands after using the toilet and before preparing and eating food Clean under fingernails daily Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Malaria Transmitted from person to person by a certain species of the Anopheles mosquito Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Life Cycle of the Malarial Parasite Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Actions of Antimalarial Drugs Interfere with life cycle of the plasmodium developing and reproducing in the mosquito Used to treat malaria Chloroquine Artemether/lumefantrine Quinine Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Uses of Antimalarial Drugs • Two terms used when discussing the uses of antimalarial drugs: – Suppression – prevention of malaria – Treatment – management of a malarial attack • Not all drugs are effective in suppressing or treating all four species that cause malaria • Some strains have developed that are resistant to some antimalarial drugs Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Uses of Antimalarial Drugs • Chloroquine – used in the treatment of extraintestinal amebiasis • Artemether/lumefantrine – used in the treatment of acute uncomplicated malaria infections in geographic regions where resistance to chloroquine has been reported • Quinine – used for the prevention or treatment of nocturnal leg cramps Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Adverse Reactions of Antimalarial Drugs Chloroquine and hydroxychloroquine: Visual disturbances, headache, nausea, vomiting, anorexia, diarrhea, abdominal cramps Artemether/lumefantrine: Adults: Headache, anorexia, dizziness, asthenia Children: pyrexia, cough, vomiting, anorexia Quinine: Cinchonism, hematologic changes, vertigo, skin rash Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Contraindications, Precautions, and Interactions of Antimalarial Drugs Chloroquine Contraindications: known hypersensitivity Precautions: liver disease, bone marrow depression, children, pregnancy Interactions: other hepatotoxic drugs, drugs that acidify the urine Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Contraindications, Precautions, and Interactions of Antimalarial Drugs Artemether/lumefantrine Contraindications: known hypersensitivity Precautions: patients with an existing QT prolongation or those taking other drugs that also cause QT prolongation Interactions: oral contraceptives, drugs that are metabolized by CYP2D6 and CYP3A4, grapefruit juice Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Contraindications, Precautions, and Interactions of Antimalarial Drugs Quinine Contraindications: known hypersensitivity, myasthenia gravis Interactions: antacids containing aluminum, digoxin, warfarin Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Patient Management Issues with Antimalarial Drugs When used for prophylaxis, therapy should begin 2 weeks before exposure and continue for 6–8 weeks after leaving the area where malaria is present Chloroquine may cause a number of visual disturbances Artemether/lumefantrine absorption is enhanced by food Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Educating the Patient and Family About Antimalarial Drugs When used for prophylaxis, drug therapy regimen is carefully reviewed with the patient If drug is to be taken once weekly, patient should select a day that will best remind him or her to take the drug Emphasize need to take the drug on an exact schedule Prophylaxis should begin 2 weeks prior to departure Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Educating the Patient and Family About Antimalarial Drugs Chloroquine Take with food or milk Avoid foods that acidify urine Drug may cause diarrhea, loss of appetite, nausea, stomach pain, or vomiting May cause discoloration of the urine Notify health care provider if: Adverse reaction become pronounced, visual changes, ringing in ears, difficulty hearing, fever, sore throat, unusual bleeding or bruising, unusual skin color or rash, muscle weakness Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Educating the Patient and Family About Antimalarial Drugs Artemether/lumefantrine Take with food Do not take with grapefruit juice Women on oral contraceptives should use an alternate form of birth control until they have had at least one menstrual cycle after drug discontinuation Notify health care provider if have symptoms of QT prolongation and medication history Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Educating the Patient and Family About Antimalarial Drugs Quinine Take with food or immediately after a meal Do not drive or perform hazardous tasks if experience blurred vision or dizziness Do not chew tablets or open capsule Notify health care provider if experience itching, rash, fever, difficulty breathing, vision problems Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Actions and Uses of Amebicides • Amebicides - kill amebas • Two types of amebiasis: – Intestinal – confined to the intestine – Extraintestinal – outside of intestine, example liver; more difficult to treat • Iodoquinol and metronidazole – used to treat intestinal amebiasis • Paromomycin – aminoglycoside with amebicidal activity used to treat intestinal amebiasis • Chloroquine – used to treat extraintestinal amebiasis Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Amebiasis Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Adverse Reactions of Amebicides Iodoquinol Various types of skin eruptions, nausea, vomiting, fever, chills, abdominal cramps, vertigo, diarrhea Paromomycin Relatively few adverse reactions Nausea, vomiting, diarrhea More serious adverse reactions: nephrotoxicity, ototoxicity Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Contraindications, Precautions, and Interactions of Amebicides Iodoquinol Contraindications: known hypersensitivity Precautions: thyroid disease, lactation Interactions: thyroid function tests Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Contraindications, Precautions, and Interactions of Amebicides Paromomycin Contraindications: known hypersensitivity Precautions: bowel disease High doses and prolonged therapy are avoided because the drug may be absorbed in large amounts by patients with bowel disease, causing ototoxicity and kidney impairment Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Patient Management Issues with Amebicides Diagnosis is made by examining the stool and considering the symptoms Local health department regulations often require investigation into source of infection Immediate family members will be tested If acutely ill or has vomiting and diarrhea, then fluid intake and output are monitored Notify health care provider if dehydration occurs Stool precautions and handwashing are necessary Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Educating the Patient and Family About Amebicides Educate about importance of completing the full course of treatment Follow directions and take medication exactly as prescribed Follow measures to control spread of infection Food handlers should not resume work until full course of treatment has been completed and stool does not contain ameba Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Educating the Patient and Family About Amebicides Iodoquinol Notify health care provider if experience nausea, vomiting or other GI distress that becomes severe Paromomycin Take three times daily with meals Report any ringing in ears, dizziness, severe GI upset, decrease in urine output or other urinary difficulties Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins ...
View Full Document

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture