Pharmacology Infectious Disease Flashcards
Ethambutol
Bacteriostatic antimycobacterial drug used in the treatment of Tb
What is ethambutol often given with for treatment of active Tb
Isoniazid, rifampin, and pyrazinamide
MOA ethambutol
Blocking bacterial arabinosyltransferase enzyme, which polymerizes carbohydrates in the bacterial cell wall. Therefore, leading to increased permeability of the cell wall
Side effects ethambutol
Eyes, optic neuritis, red green color blindness
MOA ethambutol
Bacteriostatic
Interfering with bacteria protein production, DNA replication, metabolism without directly harming the organism.
Blocks arabinosyltransferase, which polymerizes carbohydrates in the bacterial cell wall
Side effects ethambutol
Red green color blindness and decreased visual acuity. Optic neuritis, which results in color blindness, central scotoma and decreased visual acuity
Discontinuation of ethambutol can lead to what
Visual disturbances
Isoniazid
Drug used in the treatment of both latent and active tb. It can be used as a mono therapy for the treatment of latent Tb but is commonly used in a four drug regime including pyrazinamide, ethambutol, rifampin for active TB
Isoniazid is a pro drug that required bacterial catalase peroxidase enzyme to activate it and works by inhibiting the synthesis of __ __
Myolic acid
Isoniazid is metabolized by the __ via ___
Liver
Acetylation
There are two forms of the acetylation enzyme :
Fast acetylator
Slow acetylator
People with fast acetylator
Metabolize the drug more quickly than the slow acetylator
Side effects osiniazis
Vitamin B6 defiency
Hepatotoxicity and neurotoxicity
Drug induced lupus erythematosus
Indications isoniazid
TB
MOA isoniazid
Inhibits synthesis of mycolic acid
Is isoniazid used for active of latent TB
Both
How is isoniazid used for latent TB
Monotherapy
How is TB used for active TB
Four drug regime
Pyrazinamide, ethambutol, rifampin
MOA isoniazid
- must be activated by bacterial catalase peroxidase bc it is a pro drug
- inhibits synthesis of mycolic acids which is necessary for synthesis of the mycobacterial cell wall
- Metabolized in liver fast or slow depending on acetylators
Side effects isoniazid
B6 defiency (peripheral neuropathy and sideroblastic anemia)
Neurotoxicity (associated with B6 defiency)
Hepatotoxicity
Drug induced lupus
Rifampin
Bactericidal antibiotic commonly used int he treatment of active TB
MOA rifampin
Inhibits bacterial RNA stnthesisby inhibiting RNA polymerase.
Why does rifampin resistance develop quickly
Due to alteration of the binding sites on RNA polymerase so monotherapy should not be used
Monotherapy rifampin
NO
What is rifampin used in combo with
Other antibiotics
Indications for rifampin
TB
Haemophilus influenza
Leprosy
Meningitis
Rifampin is a p450 inducer….causing what
Increased rate of metabolism of other drugs that are cleared by the liver through the p450 system
Side effect rifampin
P450. Inducer
Bodily fluids (urine and tears) to become orange red in color which may be alarming but is completely benign
TB rifampin
Bactericidal antibiotic used for active TB, but never monotherapy due o high resistance rates
What is rifampin used with to treat active TB
Isoniazid, ethambutol, and pyrazinamide
MOA rifampin
Blocks RNA polymerization
Indications for rifampin
TB, haemophilus influenza, leprosy, Hansen’s disease (rifampin with dapsone and clofazimine)
Meningitis prophylaxis
Azoles (ketoconazole)
Antifungal medication that work by inhibiting fungal ergosterol synthesis, disabling the fungus from growing
Indications for azoles (ketoconazole)
Local and lessserious systemic mycoses
Side effects azoles (ketoconazole)
Liver dysfunction and testosterone synthesis inhibition
Azoles suffix
Azole
Examples of azoles
Fluconazole
Ketoconazole
Indications for azoles
Local and less serious systemic mycosis
Exception is fluconazole-used for chronic suppression of cryptococcus, along with candidiasis in AIDS patients
MOA azoles
Inhibits ergosterol synthesis leaving to defective cell membrane synthesis in fungi
Inhibits p450 to do this.
In fungus cp450 is responsible for converting lanosterol to ergosterol, and inhibition of it leads to defect cell membrane synthesis
Side effects azoles
Liver dysfunction
Inhibition of testosterone synthesis by inhibiting cholesterol desomolase which can lead to gynecomastia and hormone imbalance
Amphotericin B
Polyene medication which works by binding to ergosterol in fungal cell membranes.
MOA amphotericin B
Bind to ergosterol in fungal cell membrane
Forms membrane pores, causing electrolytes to leak, killing the cell
Indications for amphotericin B
Serious systemic mycoses
Side effects emphotericin B
Fever, chills, nephrotoxicity, arrhythmias, anemia and IV phlebitis
Indications for amphotericin B
Systemic mycosis (eg crytococcus) Fungal meningitis (eg cryptococcal meningitis) Last resort for protozoan infections (eg visceral leishmaniasis and amoebic meningoencephalitis from naegleria Fowleri)
MOA amphotericin B
Polyene that binds to ergosterol and forms membrane pores allowing leak of electrolytes, killing the fungal cell
Ergosterol is a component of fungal membranes
Side effects amphotericin B
Fever, chills, nephrotoxicity, hypotension, arrhythmias, anemia, IV phlebitis
“Shake and bake” amphotericin B
Fever and shaking
How make nephrotoxicity from amphotericin B less
Coal minister with liposomes
Hypotension amphotericin B
Bc of histamine release
Arrhythmias and amphotericin B
Due to Renal tubular damage, potassium and magnesium levels can be altered. Can lead to arrhythmias and ventricular fibrillation and cardiac failure
Flucytosine
Antifungal for treating cryptococcal meningitis and candida
What is fluctosine typically combined with
Amphotericin B
MOA flucytosine
Inhibiting DNA and RNA synthesis by being converted to 5-FU by cytosine deaminase in the fungal cell.
Side effect flucytosine
Bone marrow suppression
Indications flucytosine
Cryptococcus (cryptococcus meningitis in immunocompromised patients)
, candida (candida cystitis)
, used in combination with amphotericin B or azoles
Why is flucytosine used in combination with amphotericin b or azole antifungal
Due to its weak antifungal effects and susceptibility to resistance
MOA flucytosine
Inhibits and disrupts DNA and RNA biosynthesis by being converted to 5-FU which is an antimetabolite. In the fungal cel, cytosine deaminase converts fluctosine into 5-FU, which blocks the synthesis of thymidine ( a building block of DNA)
Side effects flucytosine
Bone marrow suppression—>anemia, leukopenia, pancytopenia, agranulocytosis
Is flucytosine toxicity reversible
None can lead to death, notably in immunocompromised patients
Griseofulvin
Oral antifungal medication used to treat infections of the skin.
Indication for griseofulvin
Ringworm and tinea infections but has several side effects
Side effects griseofulvin
Headache, confusion, teratogenic effects and inducing cytochrome p450
MOA griseofulvin
Interferes with mitotic spindle synthesis by binding to tubules and disrupting microtubule formation in fungal cells
Griseofulvin indications
Antifungal for superficial infections (ringworm or tinea-hair, nail, or large body surfaces)
INHIBITS DERMATOPHYTES which may cause ringworm or tinea. Can be used for all tineas(Curry’s, pedis, capitis, corporis)
Side effects griseofulvin
Teratogen
P450 inducer
Confusion
Headache
Terbinafine
Antifungal med which is indicated for use against dermatophytes (tinea cruris, pedis and corporis), as well as onchyomycosis
MOA terbinafine
Inhibiting squalene epoxidase, leading to fungal cell lysis and death
Indications terbinafine
Dermatophytosis (skin fungal disease-tinea pedis, tinea cruris, tinea corporis)
Onychomycosis (fungal nail infections) bc other topical agents cant penetrate nail beds deeply. It is given orally and acts systemically so can get under the nail bed
MOA terbinafine
Inhibits squalene epoxidase which is responsible for ergosterol synthesis. This changing cell membrane permeability leading to fungal cell lysis and death
Side effects terbinafine
Hepatotoxicity
GI distress
Taste disturbances
Headache
Chino candies
Antifungal meds that work by inhibiting cell wall synthesis
MOA exhinocandins
Inhibit the synthesis of beta-glucan
Indications for echinocandins
Invasive aspergillosis and candida
Side effects echinocandin
GI upset and flushing, due to histamine release
Echinocandins
Fungin
Examples of echinocandins
Caspofungin
Micafungin
Indications echinocandins
Invasive aspergillosis (intolerant. To amphotericin B or itraconazole)
Candida (also invasive candidiasis (abdominal abscesses, peritonitis, pleural cavity infections, esophagitis))
MOA echinocandins
Inhibits cell wall synthesis by inhibiting the enzyme that makes beta glucagon, which is an integral part of fungal cell walls
Side effects echinocandins
GI distress
Flushing (can promote histamine release)
Nystatin
Polyene medication that works by binding ergosterol and forming membrane pores in the fungus it is treating.
Indication for nystatin
Candidiasis and administered for topical infections bc it is too toxic for systemic administration
MOA nystatin
Amphotericin B same
Indications for nystatin
Candidiasis (vaginal, oral, cutaneous)
MOA nystatin
It is a polyene, so it binds to ergosterol and forms membrane pores , allowing leakage of electrolytes, destroying the fungal cell
Topical form of nystatin
Polyene and shares same MOA and amphotericin B . Nystatin however is too toxic for systemic use, and works well with cutaneous and topical infections
Side effects nystatin
Rash
Acyclovir (Zovirax)
Antiviral medication that inhibits viral replication in organisms of the herpes virus family
Indication for acyclovir (zoviraz)
Herpes infections and varicella zoster virus
Side effects oral acyclovir (Zovirax)
Nausea, vomiting, diarrhea and headache
Side effects IV acyclovir
Nephrotoxicity and neurotoxicity
Special considerations acyclovir
Preventing recurring episodes of herpes simplex virus and administering IV acyclovir at a slow rate
MOA acyclovir
-it is a nucleoside analog medication. Specifically a guanosine analog, and lacks 3’ group, which is necessary for addition of the next nucleotide. Thus when added to a growing DNA chain, synthesis is halted
Inhibits viral replication . This medication directly targets the thymidine kinase formed by herpesviruses and does not affect human DNA
Uses viral thymidine kinase to convert it into acyclovir monophosphate. This is converted into another compound which then inactivated and competitively inhibits DNA polymerase, halting DNA synthesis in viral cells
Indications acyclovir
HSV
Varicella zoster
Topical acyclovir
Initial genital herpes simplex
Oral acyclovir
Both initial and recurrent oral and genital herpes infections
Varicella within 24 hours of developing rash
High doses if older adult
IV acyclovir
Severe genital herpes infection, or immunocompromised patients with oral herpes
Immunocompromised patients with varicella zoster
Side effects acyclovir oral
Headache
GI distress
Side efects acyclovir IV
CNS toxicity (esp renal impairment) Nephrotoxicity (buildup of acyclovir in body can causes neurotoxicity like agitation, tremors, hallucinations, and delirium. Also sudden jerking))
Nephrotoxicity (crystalline nephropathy-increased BUN and creatinine)
Ganciclovir
Antiviral medication used to treat CMV infections int he immunocompromised
MOA ganciclovir
Guanosine analog, that is phosphorylation by a viral kinase to form a competitive inhibitor of nucleotide incorporation into DNA)…thus inhibiting viral DNA polymerase
Side effects ganciclovir
Hematologic also effects, along with renal toxicity
Indications ganciclovir
CMV
Immunocompromised (HIV, more susceptible to CMV)
MOA ganciclovir
Guanosine analog which is phosphorylation by a viral kinase encoded by CMV during infection…leading to the formation of ganciclovir triphosphate
Disrupts DNA synthesis-ganciclovir triphosphate is a competitive inhibitor of nucleotide incorporation into DNA, leading to disrupted DNA synthesis
Ganciclovir triphosphate, which is formed by viral processing of ganciclovir, preferentially inhibits viral DNA polymerase, disrupting viral DNA synthesis
Side effects ganciclovir
Hematologic effects
Nephrotoxicity
Foscarnet
Antiviral medication used to treat CMV retinitis in immunocompromised that have failed ganciclovir therapy or acyclovir resistant HSV
Indications for foscarnet
CMV retinitis
Acyclovir resistant HSV
MOA foscarnet
Inhibiting viral DNA polymerase and does not require activation by a viral kinase
Side effect foscarnet
Nephrotoxicity
Resistance when their DNA polymerase mutates
MOA foscarnet
- does not require activation by thymidine kinases
- Inhibits viral DNA polymerase by binding to pyrophosphate(it is a pyrophosphate analog)-binding site of this enzyme..inhibiting elongation of viral DNA
How does foscarnet gain resistance
Mutate DNA polymerase so foscarnet cant bind anymore
Side effects foscarnet
Nephrotoxicity, electrolyte abnormalities
What sort of electrolyte abnormalities do you get with foscarnet
Hypokalemia, hypocalcemia, hypomagnesemia
What level of k is hypokalemia and what are symptoms
Under 3.5 mEq/L
Muscle weakness, arrhythmias, presence of U waves, constipation, hyporeflexia
What level is hypocalcemia and what are the symptoms
8.5 mg/dL
Decreased bone density, muscle spasms, tetany, increased DTR, prolonged QT interval
What level is hypomagnesia and what are symptoms
1.5mEq/L
Increased DTR, seizures, muscle cramps, tremors, insomnia, and tachycardia
Fusion inhibitors / entry inhibitors
Medications that are often used in combination therapy to prevent binding, fusion and entry of the HIV vision into the host cell.
Two fusion inhibitors
Enfuvirtide
Maraviroc
MOA enfuviritde
Binding gp41 (a HIV protein) and interferes with this ability to fuse CD4 cells
MOA maraviroc
Binds CCR5 preventing its interaction with viral gp120
Indications fusion inhibitors
HIW infection, as part of multidrug therapy
Maraviroc MOA
Binds CCR5 on CD4 (chemokine receptor), preventing its interaction with viral gp120 disallowing viral entry into the human cell
Enfuvirtide MOA
Binding to gp21 (an HIV protein) and interferes with its ability to fuse with CD4 cells
Inhibits viral entryleading to defective fusion
Side effects fusion proteins
Skin reactions at injection sites
Protease inhibitors
Inhibit the maturation of new viruses, by selectively binding to viral proteases and inhibiting replication.
Indication for protease inhibitors
HIV/AIDS and hepc
Side effects protease inhibitors
Nephropathy, lidodystrophy, hyperglycemia, and GI distress
Suffix protease inhibitors
Navir
Examples of protease inhibitors
Ritonavir and indinavir
HIV and protease inhibitors
Inhibit HIV-1 protease
Protease inhibitors and hepatitis C
Treat hepatitis caused by hepatitis C
MOA protease inhibitors
Inhibit protease, which is required for viral replication. (Viral proteases cleave proteins for viral maturation)
Virus maturation
Occurs by assembling functional units, which are made from polypeptides that were cleaved by protease. By inhibiting viral protease, these functional protein precursors cant be cleaved, and a new, mature, infectious virus cant be assembled.
Side effects protease inhibitors
GI distress,
Nephropathy
Lipodystrophy(abnormal degeneration of fat)
Hyperglycemia (insulin resistance
Integrate inhibitors
Class of antiretroviral medication, which are used to treat HIV.
MOA integrate inhibitors
Inhibit HIV genome integration into the host DNA, by inhibiting HIV integrate. This medication can lead to insomnia and hypercholestermia.
Suffix of integrate inhibitors
Gravir
Example of integrate inhibitors
Raltegravir
Indications integrate inhibitors
HIV, with other meds
MOA integrate inhibitors
Blocks insertion of HIV viral genome into host chromosome
-block viral genome integration by reversible inhibiting HIV integrate, the viral enzyme which integrate the viral genome
Side effects integrate inhibitors
Hypercholestermia
Increased LFTs (AST, ALT and bilirubin)
Insomnia
Increased CK (muscle pain)
Non nucleoside reverse transcriptase inhibitors (NNRTIs)
Class of medication designed to bind to reverse transcriptase to inhibit viral DNA elongation.
What are NNRTIs often combined with
Other therapies
What is different about NNRTI from NRTI
Don’t require intracellular metabolism
Side effects NNRTIs
Hepatotoxicity, vivid dreams and CNS effects
NNRTIs contraindicated
Pregnant women
Indication NNRTI
HIV
MOA NNRTI
- dont need intracellular metabolism or phosphorylation
2. inhibit reverse transcriptase(different site from NRTI), preventing viral DNA from being transcripts
Side effects NNRTI
Rash
Hepatotoxicity, vivid dreams and CNS symptoms
Which NNRTI causes vivid dreams and CNS symptoms
Efavirenz
Why no give NNRTI to pregnant women
Delavirdine and efavirenz
Teratogenic
Examples of NNRTI
Nevirapine, rilpivirine, efavirenze, delavirdine, etravirine
Efavirenze
Neuropsychiatric effects
Delavirdine and efavirenze
Teratogenic activity contraindicated in patients
Nevirapine (viramune)
For HIV AIDS
Used in triplecombination due to viral resistance
Rilpivirine (edurant)
Second generation NNRTI
Higher potency and longer half life and less side effects
Delavirdine (DLV, rescriptor)
Not HAART bc lower efficacy than other NNRTI. Associated with teratogenic effects and contraindicated in pregnancy
Efavirenz (EFV, sustiva)
Part of HAART
Also combined with other for prophylaxis of HIV transmission. Has dopaminergic and serotonergic activity, leading to neuropsychiatric adverse effects
What CNS effects do you get with efavirenz
Depression, anxiety, hallucinations, aggression, suicidal ideation, sleep disturbances)
How can you alleviate CNS side effects from efavirenz
Cyproheptadine
Etravirine (ETR, intelence)
Second generation NNRTI designed to be active against HIV with mutations that display resistance to the two most commmonly prescribed first generation NNRTI
NRTI (nucleoside reverse transcriptase inhibitors)
Antiretroviral drugs used for HIV work by competitively inhibiting nucleotide binding to reverse transcriptase, and also terminate the elongating DNA chain
Adverse
General prophylaxis and during pregnancy to decrease transmission
NRTI activation
Int he cel, requiring phosphorylation
Indication for NRTI
HIV zidovudine (Zdz) for general prophylaxis and pregnant women to reduce transmission
MOA NRTI
1.activation in the cell by phosphorylation2.competitively inhibit nucleotide binding to reverse transcriptase, preventing the virus from making a DNA copy of its RNA
Chain termination
-lack of 3’-OH group in the incorporated nucleotide analogue prevents DNA chain elongation and therefore, the viral DNA growth is terminated
What are the two groups of NRTI
Nucleoside reverse transcriptase inhibitors
Nucleotide reverse transcriptase inhibitors
Nucleoside reverse transcriptase inhibitors
Didanosine (DDI) Emtricitabine (FTC) Abacavir (ABC) Lamivudine (3TC) Stavudine (d4T) Zidovudine (Zdv)
DEALSZ
Nucleoside analog medication
Tenofivir (TDF)
Didanosine DDI
Adenosine analog
Adverse reaction didanosine
Diarrhea, nausea, vomiting, abdominal pain, fever, headache rash, peripheral neuropathy
Emtricitabine (FTC)
Analog to cytidine
Treat HIV and hep B
Rare side effects-may get hepatotoxicity or lactic acidosis
Abacavir (ABC)
Nucleoside analog reverse transcriptase inhibitor analog of guanosine
Oral-high bioavailability
Side effects abacavir
Nausea, headache, fatigue, vomiting, hypersensitivity reaction, diarrhea, fever/chills , depression, rash , anziety, URI, ALT, AST up, hypertriglyceridemia, lipodystrophy
Lamivudine (3TC)
Cytidine analogue
Inhibit HIV reverse transcriptase and hep b reverse transcriptase
Stavudine (d4T)
Thymidine analogue which inhibits HIV RT by competing with natural substrate, thymidine triphosphate. Then leads to termination of DNA replication by incorporating into the DNA strand
Side effects stavudine (d4T)
Peripheral neuropathy and lipodystrophy, so less commonly used in developing countries)
Zidovudine (Zdv)/AZt
For selectively inhibiting HIVs reverse transcriptase, the enzyme that the virus uses to make a DNA copy of its RNA.
Side effects zidovudine AZt
Anemia, neutropenia, hepatotoxicity, cardiomyopathy, myopathy
Why is AZt given as part of HAART
Resistance
Tenofovir
Nucleoside analogue reverts transcriptase inhibitor
HIV hep b
Side effects tenofovir
Nausea, comiting, diarrhea, weakness
Renal complications-acute renal failure, falcon I syndrome, proteinuria, tubular necrosis
NRTI toxicity
Medications that inhibit RT in HIV
Toxicities of NRTI
Bone marrow suppression, rash, neuropathy, lactic acidosis, pancreatitis, anemia
Which NRTI cause pancreatitis with alcohol
DIDANOSINE
How reverse bone marrow suppression with NRTI
G-CSF and erythropoietin
Cidofovir
Antiviral med for CMV retinitis in immunocompromised patients and is also indicated for acyclovir resistant HSV
MOA cidofovir
Long half life and works by preferentially inhibit viral DNA polymerase
Active and doesn’t require phosphorylation
Side effect cidofovir
Nephrotoxicity, which can be decreased when co administered with probenecid and IV saline
Indications cidofovir
CMV retinitis in immunocompromised patients
Acyclovir resistant HSV
MOA cidofovir
Inhibits viral DNA polymerase by selectively inhibiting viral DNA polymerases thus inhibiting viral DNA synthesis during its reproduction cycle
Side effects cidofovir
Nephrotoxicity
How prevent nephrotoxicity with cidofovir
Administer with probenecid and IV saline
HAART
Highly active antiretroviral therapy
Medication regime for patients who display AIDS defining lesions or have CD4 count below 350 internationally or 500 in US
What is HAART
2 NRTI+1 of the following: a NNRTI, a protease inhibitor or an integrate inhibitor
When initiate HAART
When HIV diagnosis
To reduce disease progression and prevent transmission
How many drugs are in HAART
3
What are the 2NRTIs(nucleoside reverse transcriptase inhibitors)
Inhibit binding of nucleotides to reverse transcriptase and by terminating the DNA chain
What is the 3rd HAART drug
NNRTI Treats HIV by inhibiting nucleotide binding to reverse transcriptase at a different site of action than NRTI Or Protease inhibitor Or Integrate inhibitor
Ribavirin
Antiviral medication with activity against both RNA and DNA viruses.
Indication for ribavirin
Hep c and viral hemorrhagic fevers, off label RSV
Side effect ribavirin
Teratogen, hemolytic anemia
MOA ribavirin
Hypermutation in RNA viruses-incorporated into RNA base pairs guanine and adenosine. Induces hypermutations in RNA dependent replication, leading to virus death
Inhibits inosine monophosphate dehydrogenase-inhibits cellular inosine monophosphate dehydrogenase, depleting intracellular GTP which may play a role
Indications ribavirin
Hep c
Viral hemorrhagic fever
RSV
Side effects ribavirin
Hemolytic anemia
Teratogen
Zanamivir (relenza) and oseltamivir (tamiflu)
Antiviral medications used to treat and provide prophylaxis against influenza A and B.
MOA zanamivir and oseltamivir
Bind to neuraminidase, preventing the virus from escaping its host cell and infecting others
Indications zanamivir and oseltamivir
Influenza a and b
Prophylaxis for people exposed to flu
MOA zanamivir and oseltamivir
Inhibits release of new virus 9render virus unable to escape from the host cell that it has infected. Thus unable to infect other cells)
Work to inhibit viral transmission by binding to the active site of viral neuraminidase. This makes the infected host cell unable to bud