Pharmacology Flashcards
1
Q
How many people are infected with intestinal nematodes?
A
More than 1 billion people
This includes millions infected with filarial nematodes, flukes, and tapeworms.
2
Q
What are the three classes of parasitic helminths in humans?
A
- Nematodes (roundworms)
- Cestodes (tapeworms)
- Trematodes (flukes)
Helminths are multicellular parasites with complex life cycles.
3
Q
How are helminthic infections transmitted?
A
- Ingestion
- Skin penetration
- Vector bite
- Consumption of the host as food
Regions of high prevalence depend on climate, hygiene, and exposure to vectors.
4
Q
What are anthelminthic drugs used for?
A
Treatment of symptomatic disease and mass drug treatment programs
They are categorized by their chemical structures and/or the class of parasitic worms they target.
5
Q
Name three benzimidazole drugs.
A
- Albendazole
- Mebendazole
- Triclabendazole
Benzimidazoles bind β-tubulin and prevent polymerization, leading to the death of the worm.
6
Q
What is the mechanism of action of benzimidazoles?
A
They bind β-tubulin and prevent polymerization of tubulin dimers into microtubules
This interrupts glucose uptake, reproductive, and metabolic processes in helminths.
7
Q
What types of infections is albendazole effective against?
A
- Intestinal infections (ascariasis, trichuriasis, hookworms, enterobiasis)
- Filariasis
- Tissue nematode infections (trichinellosis, toxocariasis)
- Cestode infections (hydatid disease, neurocysticercosis)
Albendazole is well tolerated with potential side effects including abdominal pain and nausea.
8
Q
What is the preferred agent for treating sheep liver fluke infection?
A
Triclabendazole
It may cause QTc interval prolongation.
9
Q
What is Pyrantel pamoate used for?
A
Treatment of pinworms and other intestinal nematode infections
It is available in the US without a prescription.
10
Q
Name the threadlike nematodes that cause filariasis.
A
- Wuchereria bancrofti
- Brugia malayi
- B. timori
- Loa loa
- Onchocerca volvulus
- Mansonella spp.
These are transmitted by biting flies and mosquitoes.
11
Q
What is the drug of choice for lymphatic filariasis?
A
Diethylcarbamazine (DEC)
It is effective against loiasis and Mansonella streptocerca.
12
Q
What are the side effects of DEC?
A
- Fever
- Anorexia
- Nausea
- Vomiting
- Headache
- Arthralgias
These effects usually disappear after a few days.
13
Q
What is Ivermectin primarily used for?
A
Treatment of onchocerciasis and strongyloidiasis
It has a broad spectrum of activity against microfilaria and other nematodes.
14
Q
What is the mechanism of action of Ivermectin?
A
Paralyzes nematodes and arthropods by intensifying chloride channels in nerves and muscles
It kills microfilariae but not adult filariae.
15
Q
What indirect activity does Doxycycline have?
A
Depletes the bacterial endosymbiont Wolbachia, important for helminth fertility
It leads to sterility in adult female filarial worms.
16
Q
What is Praziquantel used for?
A
- Schistosomiasis
- Intestinal, lung, and liver flukes (not Fasciola)
- Intestinal tapeworms
It causes calcium influx and spastic paralysis of helminths.
17
Q
What is a key strategy for the elimination of filariasis?
A
Administration of annual doses of drug to the population
This is a WHO strategy involving DEC and albendazole or ivermectin.
18
Q
What are common nematode infections?
A
- Ascaris lumbricoides
- Trichuris trichiura
- Necator americanus
- Ancylostoma duodenale
- Strongyloides stercoralis
- Enterobius vermicularis
Nematodes are elongated roundworms with a complete digestive system.
19
Q
What are elongated roundworms that have a complete digestive system called?
A
Nematodes
20
Q
What types of infections can nematodes cause?
A
Infections of intestine, blood/lymph, and tissues
21
Q
Name three common medications used to treat nematode infections.
A
- Benzimidazoles
- Pyrantel pamoate
- Diethylcarbamazine
- Ivermectin
22
Q
Which class of drugs does Albendazole belong to?
A
Benzimidazoles
23
Q
What is the mechanism of action of benzimidazoles?
A
Bind β-tubulin, inhibit polymerization of tubulin dimers into cytoplasmic microtubules in parasites
24
Q
Fill in the blank: The active metabolite of Albendazole is _______.
A
albendazole sulfoxide
25
How is Albendazole absorbed and what enhances its absorption?
Absorption is variable and enhanced by fatty meal
26
What is the half-life (t½) of albendazole sulfoxide?
8-12 h
27
What is the primary route of excretion for Mebendazole?
Fecal excretion
28
What is the average half-life (t½) of Mebendazole?
~3 h
29
What are some common adverse effects of Albendazole?
* Abdominal discomfort
* Diarrhea
* Rash
* Alopecia
* Dizziness
30
True or False: High doses of Albendazole may lead to hepatitis or myelosuppression.
True
31
What is the mechanism by which benzimidazoles impair glucose uptake in parasites?
Inhibit tubulin- and microtubulin-dependent glucose uptake
32
List the types of intestinal nematodes treated effectively by Mebendazole.
* Ascariasis
* Trichuriasis
* Hookworms
* Enterobius vermicularis
* Trichinella spiralis
33
What is the role of Triclabendazole in treating Fasciola hepatica?
Treats sheep liver fluke infections
34
What adverse effects are associated with Mebendazole?
* Abdominal pain
* Distention
* Diarrhea
* Low incidence of systemic toxicity
35
What should be monitored when using drugs that prolong QT interval?
Drug interactions with QT prolonging drugs
36
Fill in the blank: The primary metabolism of Mebendazole occurs in the _______.
liver
37
What type of treatment programs is Albendazole used in?
Mass treatment programs for filarial infections
38
Which benzimidazole is no longer available?
Thiabendazole
39
What is the mechanism of action of depolarizing neuromuscular blockers?
Causes release of ACh and inhibits cholinesterase
## Footnote
This leads to activation of cholinergic nicotinic receptors in somatic muscles, resulting in depolarizing neuromuscular blockade and paralysis.
40
What is Pyrantel pamoate used for?
Intestinal antihelminthic drug
## Footnote
Effective against mature and immature pinworms, ascariasis, Trichostrongylus orientalis, and hookworms.
41
List the helminthic infections treated by Pyrantel pamoate.
* Enterobius vermicularis (pinworms)
* Ascariasis
* Trichostrongylus orientalis
* Ancylostoma duodenale
* Necator americanus
42
What is the absorption profile of Pyrantel?
Minimal oral absorption
43
What populations is Pyrantel safe for?
Adults, children ≥2 years old, and pregnant individuals
44
What is the primary treatment for lymphatic filariasis?
Diethylcarbamazine (DEC)
## Footnote
Most cases are caused by Wuchereria bancrofti.
45
What are the common adverse effects of Diethylcarbamazine?
* Anorexia
* Nausea
* Headache
* Vomiting
46
What is the contraindication for Diethylcarbamazine?
Onchocerciasis
47
What is the suggested mechanism of action of Diethylcarbamazine against microfilariae?
* Alteration of surface membranes sensitizes microfilariae to phagocytosis
* Disruption of microtubule formation
* Interference with intracellular processing
48
What is the half-life of Diethylcarbamazine?
Approximately 18 hours
49
What is a serious potential reaction to Diethylcarbamazine treatment in onchocerciasis patients?
Mazzotti reaction
## Footnote
This can lead to severe reactions including irreversible eye damage.
50
What is the primary treatment for Onchocerciasis?
Ivermectin
## Footnote
DEC is contraindicated for this condition.
51
What is the effect of DEC on adult worms?
Mechanism of action is unknown
52
What is the distribution profile of Diethylcarbamazine?
Widely distributed, crosses the blood-brain barrier
53
What are the recommended treatment strategies in mass treatment programs for helminthic infections?
Single antihelminthic doses annually or biannually to the entire population
54
What are common symptoms of the Mazzotti reaction?
* Intense itching
* Papular rash
* Enlarged tender lymph nodes
* Fever
* Tachycardia
* Arthralgia
* Headache
55
What is the primary causative agent of loiasis?
Loa loa
56
What condition is caused by Wuchereria bancrofti?
Lymphatic filariasis
57
What are the symptoms associated with high worm burdens in DEC treatment?
Severe side effects including retinal hemorrhages and encephalopathy
58
True or False: Pyrantel has a marked effect on neuromuscular function in mammalian species.
False
59
Fill in the blank: DEC is contraindicated in the treatment of _______.
Onchocerciasis
60
What is the primary complication caused by the worms in the eye?
Eye inflammation, bleeding, and other complications
61
What is the drug of choice for the treatment of Onchocerciasis?
Ivermectin
62
What infections can Ivermectin treat?
* Onchocerciasis
* Strongyloidiasis
* Mansonella infections
63
What is the mechanism of action of Ivermectin in microfilariae?
Binds glutamate-gated Cl‒ channels in nerve and muscle cells, increasing permeability to Cl‒ ions, leading to paralysis and parasite death
64
What is the recommended way to take Ivermectin?
On an empty stomach, although some experts recommend taking it with food to enhance absorption
65
What is the half-life of Ivermectin?
~18 hours
66
Which type of infections is Ivermectin microfilaricidal against?
Microfilariae, NOT adult worms
67
Is Ivermectin used for L. loa infection?
No
68
What are some ectoparasite infections treated by Ivermectin?
* Scabies
* Head lice
69
What is the primary effect of Ivermectin on nematodes?
Paralysis, particularly of the nematode pharynx, blocking oral ingestion of nutrients
70
What is the Mazzotti reaction?
An inflammatory reaction due to the killing of microfilariae, usually limited to mild itching and tender, swollen lymph nodes
71
What are potential adverse effects of Ivermectin?
* Mild itching
* Tender, swollen lymph nodes
* L. loa encephalopathy in cases of high microfilariae burden
72
What is the safety of Ivermectin during pregnancy and breastfeeding?
Safety not established
73
What are the components of the 3-drug regimen for lymphatic filariasis elimination?
* Ivermectin
* DEC
* Albendazole
74
What is the benefit of Ivermectin for onchocerciasis in coendemic areas?
Benefits felt to outweigh the risk of serious inflammatory adverse events from treatment of loiasis
75
What is the mechanism of action of Doxycycline against filarial nematodes?
Binds 30S ribosome, blocking aa-tRNA binding and addition of amino acids to the growing peptide chain
76
What is the macrofilaricidal activity of Doxycycline against?
* W. bancrofti
* Brugia species
* O. volvulus
77
How long is Doxycycline typically administered for macrofilaricidal activity?
6 weeks
78
What is the outcome of Doxycycline treatment in adult female worms?
Sterility
79
What is the body structure of tape worms?
Flat, segmented body
## Footnote
Tape worms are classified as cestodes.
80
How do cestodes attach to the host's intestinal wall?
Using suckers, hooks, or sucking grooves
81
What is the treatment for Taenia solium?
Praziquantel
82
What are proglottids?
Segments that extend from the scolex of a tapeworm
83
What serious condition can Taenia eggs cause when consumed by humans?
Cysticercosis, including neurocysticercosis
84
What is the larval form of Taenia solium associated with?
Cysticercosis, Neurocysticercosis
85
What is the treatment for neurocysticercosis caused by Taenia solium?
Surgical excision, Albendazole, Praziquantel
86
What is the treatment for Echinococcus granulosus infections?
Albendazole, Surgical removal
87
What are the major types of parasitic flatworms?
Cestodes and Trematodes
88
What is the primary treatment for trematode infections?
Praziquantel
89
What is the common name for Fasciolopsis buski?
Giant intestinal fluke
90
What is the condition caused by Clonorchis sinensis?
Clonorchiasis
91
Fill in the blank: Praziquantel is effective against _______.
most trematode and cestode infections
92
What is the mechanism of action of Praziquantel?
Increases permeability of cestode and trematode cell membranes to Ca2+
93
What are common adverse effects of Praziquantel?
Abdominal pain, nausea, diarrhea, headache, dizziness, drowsiness
94
True or False: Praziquantel is considered safe during pregnancy.
True
95
What can be a severe reaction to neurocysticercosis treatment?
Inflammatory reactions leading to disability/death
96
What are drug-drug interactions associated with Praziquantel?
Exacerbation of cardiac arrhythmias, CNS pathology
97
What is the usual dosing schedule for Praziquantel?
3x daily for 1-2 days, 10-14 days for neurocysticercosis
98
What is the effect of high-carbohydrate meals on Praziquantel?
Increases plasma concentration
99
What is the half-life of Praziquantel?
Approximately 1 hour
100
What type of infections does Praziquantel treat?
Schistosome infections and most trematode and cestode infections
101
What are the three major groups of helminths that infect humans?
Nematodes, cestodes, trematodes
102
What is the primary goal of helminthic infection treatment in developing countries?
Control of infection, alleviating disease symptoms, and decreasing transmission
103
What are benzimidazoles and how do they work?
Broad spectrum agents that inhibit polymerization of tubulin dimers into microtubules, affecting glucose uptake and energy metabolism
104
Which benzimidazole is used for luminal and tissue nematode infections?
Albendazole
105
What is Mebendazole used for?
Luminal nematode infections
106
What infection is Triclabendazole used to treat?
Fasciola hepatica (sheep liver fluke) infections
107
What is a potential side effect of Triclabendazole?
QT interval prolongation
108
How does Pyrantel pamoate work?
Induces muscle paralysis by depolarizing neuromuscular block on AcH receptors
109
What infections is Pyrantel pamoate used to treat?
Pinworm, hookworm infections, and ascariasis
110
What is the mechanism of action of Diethylcarbamazine (DEC)?
Microfilaricidal and filaricidal activity against some adult worms
111
Which infection is Ivermectin primarily used to treat?
O. volvulus river blindness infection
112
What severe reaction can DEC cause?
Mazzotti inflammatory reaction
113
What is the role of Doxycycline in treating helminthic infections?
Depletes Wolbachia, leading to sterility of adult female worms
114
What is the drug of choice for schistosomiasis?
Praziquantel
115
What is the treatment for Enterobius vermicularis (pinworm)?
Pyrantel pamoate; Mebendazole
116
What are the treatments for Ascaris lumbricoides (common roundworm)?
Albendazole; Mebendazole
117
What is the treatment for Wuchereria bancrofti?
Diethylcarbamazine
118
Which drug is used for the treatment of neurocysticercosis?
Albendazole plus Praziquantel (and dexamethasone)
119
What is the treatment for schistosomes and most other trematodes?
Praziquantel
120
Fill in the blank: The drug _______ is used to treat Fasciola hepatica infections.
Triclabendazole
121
True or False: Ivermectin has both microfilaricidal and filaricidal activity.
False
122
what aspects of the PK-PD profile for albendazole make it very effective against parasites that cause extraintestinal symptoms
distributes to CSF
123
what characteristics of Mebendazole's PK-PD profile make it generally well tolerated
poorly absorbed; 90% stays in the intestinal lumen
124
What OTC anthelminthic agent is very effective against pinworms
pyrantel pamoate
125
Filaria are a type of nematode transmitted by biting flies and mosquitoes. they are assoc. w/ extraintestional infection of what system?
lymphatics causing elephantiasis
126
Hydatid cysts are assoc. w/ what tapeworm?
echinococcus granulosus
127
why is DEC a CI in pt. w/ onchocerciasis
can precipitate to a fatal inflammatory response called Mazzotti reaction; pts. w/ O. volvulus coinfection should not receive DEC
128
T or F: ivermectin is also be used for ectoparasites like lice
True
129
T or F: ivermectin can target both larvae & adult strongyloidiasis
false
it can target adults in the small intestine but not the larvae that travel to other organ
130
what is the 1st line drug for schistosomiasis?
praziquantel
131
neurocysticerosis is caused by what parasite?
T. solium
132
What is the drug of choice for Loa loa african eye worm infections
DEC
133
T or F: DEC and cause encephalopathy in pts. w/ loa loa
True
134
what pinworm is albendazole not affective against what pinworm
enterobius vermicularis
