Title: ANTIBIOTICS ANTIVIRALSA ANTIFUNGALS ANTI-TUBERCULAR ANTIMALARIAL ANTIHELMINTHIC ANTIMYCOBACTERIAL ANTIVIRALS ANTIBIOTICS COMMONLY KNOWN AS ANTIMICROBIALS
1ANTIBIOTICSANTIVIRALSAANTIFUNGALSANTI-TUBERCULA
RANTIMALARIALANTIHELMINTHICANTIMYCOBACTERIALAN
TIVIRALSANTIBIOTICSCOMMONLY KNOWN AS
ANTIMICROBIALS
DRUGS FOR BUGS ??
2WHAT IS AN INFECTION?
- A disease or condition caused by a microorganism
that releases toxins or invade body tissues - Localized infection
- Systemic infection
3WHO IS MORE LIKELY TO GET AN INFECTION?
- SKIN NOT INTACT
- BLOOD SUPPLY IMPAIRED
- NEUTROPENIA
- MALNUTRITION
- SUPPRESSION OF NORMAL BACTERIAL BALANCE
- SUPPRESSION OF THE IMMUNE SYSTEM
- DIABETES
- CHRONIC ILLNESS
- ADVANCED AGE
4Infections Sites of Origin
- Community-associated infections
- An infection that is acquired by a person who has
not been hospitalized or had a medical procedure
(such as dialysis, surgery, catheterization)
within the past year
5 Infections Sites of Origin (contd)
- Healthcare-associated infections
- Contracted in a hospital or institutional setting
- Were not present or incubating in the patient on
admission to the facility - More difficult to treat because causative
microorganisms are often drug resistant and the
most virulent - One of top ten leading causes of death in the
U.S. - MRSA most common
- Previously known as nosocomial
6Healthcare-Associated Infections Prevention
- Hand washing
- Antiseptics
- Disinfectants
7Healthcare-Associated Infections Prevention
(contd)
- Disinfectant
- Kills organisms
- Used only on nonliving objects
- Antiseptic
- Generally only inhibits the growth of
microorganisms but does not necessarily kill them - Applied exclusively to living tissue
8FUNCTIONS OF ANTIBIOTICS
- BACTERICIDAL Kills or destroys microorganisms
- BACTERIOSTATIC Retards the growth of
microorganisms
9IDENTIFICATION OF BACTERIA
- GRAM TESTING
- CULTURE AND SENSITIVITY TESTING
- SEND SPECIMEN FIRST !!!!!
- START ANTIBIOTIC BEFORE CULTURE RESULTS ARE KNOWN
(EMPIRIC THERAPY) - RX MAY CHANGE WHEN CULTURE IS GROWN
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11BACTERIAL RESISTANCE
- Bacterial resistance
- PENICILLINASE
- USED BY BACTERIA TO DESTROY PCN
- BETA-LACTAMASE
- BREAKS DOWN THE STRUCTURE OF THE ABX INACTIVATING
THE DRUG
12ANTIMICROBIAL RESISTANCE
- UNWISE USE OF ANTIBIOTICS
- ANTIBIOTICS ARE NOT EFFECTIVE AGAINST VIRAL
INFECTIONS - WHEN VIRAL SYMPTOMS PERSIST, ABX WILL BE USED FOR
A SECONDARY BACTERIAL INFECTION - ANTIBIOTICS MAY BE PRESCRIBED AS PROPHYLACTIC TO
ANOTHER TREATMENT OR PROCEDURE
13ANTIMICROBIAL RESISTANCE
- METHICILLIN RESISTANT STAPHYLOCOCCUS AUREUS
MRSA - HAND WASHING AND GLOVING
- GOAL IS TO AVOID HEALTHCARE ASSOCIATED INFECTIONS
- COLONIZED MEANS HARBORS THE BACTERIA
14ANTI-INFECTIVES / ANTIBIOTICS
- PROPER DOSE AND DURATION OF THERAPY
- AVERAGE OF 7 10 DAYS OF THERAPY
- SPECIFY TIME OF DAY TO TAKE THE DRUGS TO MAINTAIN
THERAPEUTIC LEVELS - PATIENT MUST COMPLETE ENTIRE RX
- NEVER SAVE FOR USE AT ANOTHER TIME
- NEVER SHARE WITH ANOTHER PERSON
15ADVERSE REACTIONS TO ABX
- HYPERSENSITIVITY (allergy)
- Requires at least one exposure to the drug
- Mild
- Rash, pruritus, urticaria
- Severe
- Anaphylaxis
- Laryngospasms (wheezing)
- Dyspnea
- Decrease in blood pressure
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18ADVERSE REACTIONS TO ABX
- CROSS-SENSITIVITY REACTIONS
- If allergic to one antibiotic, allergic to
antibiotics from same family - EXAMPLE ALLERGY TO PCN, ALSO MAY BE ALLERGIC TO
CEPHALOSPORIN
19STEVENS-JOHNSON SYNDROME
- Severe (can be fatal) hypersensitivity reaction
caused by reaction to a medication - Typically involves the skin and mucous membranes
developing severe inflammation progressing to
necrosis of the tissues. Can also progress to the
lining of internal organs. - TABERS TOXIC EPIDERMAL NECROLYSIS
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23SUPERINFECTION
- A secondary infection that occurs during
antibiotic therapy in which normal flora are
destroyed
24Superinfection
- LOCATION OF INFECTION
- GROIN
- AXILLA
- MOUTH
- UNDER BREAST TISSUE
- ANY WARM MOIST AREA
- OFFENDING ORGANISM
- YEAST
- BACTERIA
25Candida Yeast / Thrush
26 NURSING RESPONSIBILITIES
- PATIENTS RESPONSE TO THERAPY
- EVALUATE TEMPERATURE, APPETITE AND GENERAL LEVEL
OF WELLNESS - FLUID INTAKE
- DRUGS ARE NEPHROTOXIC
- ADVISE PATIENT TO INCREASE PO INTAKE
- FULL GLASS OF WATER WITH MED
- WATER WILL DECREASE GI SYMPTOMS
- OTHER MEDS
- LOOK FOR CONTRAINDICATED MEDS
- LOOK FOR HERBAL INTERACTIONS
27CHARACTERISTICS OF ANTIBACTERIALS
- BROAD SPECTRUM
- NARROW SPECTRUM
- MECHANISM OF ACTION
28BROAD SPECTRUM ANTIBIOTIC
- AN ANTIBIOTIC THAT IS EFFECTIVE AGAINST BOTH
GRAM-NEGATIVE AND GRAM-POSITIVE BACTERIAL SPECIES - BROAD-SPECTRUM AGENTS INCLUDE
- CARBAPENEMS
- EXTENDED-SPECTRUM CEPHALOSPORINS
- BETA-LACTAM/BETA-LACTAMASE INHIBITOR COMBINATIONS
- FLUOROQUINOLONES
29NARROW SPECTRUM ANTIBIOTIC
- AN ANTIBIOTIC EFFECTIVE AGAINST A LIMITED NUMBER
OF MICROORGANISMS. - EXAMPLES OF NARROW-SPECTRUM AGENTS INCLUDE
- PENICILLIN G
- MACROLIDES
- NITROFURANTOIN
- METRONIDAZOLE
- AZTREONAM
- NALIDIXIC ACID
-
30MECHANISMS OF ACTION
- Inhibition of bacterial cell wall synthesis
- Inhibition of protein synthesis
- Disruption of cell membranes
- Inhibits cell reproduction
- Inhibits cell metabolism
31Antibiotics Sulfonamides
- One of the first groups of antibiotics
- Sulfadiazine
- Sulfamethoxazole
- Sulfisoxazole
- Often combined with another antibiotic
- Sulfamethoxazole combined with trimethoprim (a
nonsulfonamide antibiotic), known as Bactrim,
Septra, or co-trimoxazole (SMX-TMP) - This combination is used commonly
32Sulfonamides Mechanism of Action
- Bacteriostatic action
- Prevent synthesis of folic acid required for
synthesis of purines and nucleic acid - Do not affect human cells or certain bacteria
- Only affect organisms that synthesize their own
folic acid
33Sulfonamides Indications
- Effective against both gram-positive and
- gram-negative bacteria
- Treatment of UTIs caused by susceptible
- strains of
- Enterobacter , Escherichia coli, Klebsiella ,
Proteus mirabilis, Proteus vulgaris,
Staphylococcus aureus
34Sulfonamides Indications (contd)
- Urinary tract infections
- Upper respiratory tract infections
35Sulfonamides Adverse Effects
- Body System Adverse Effects
- Blood Hemolytic and aplastic anemia,
agranulocytosis, thrombocytopenia - Integumentary Photosensitivity, exfoliative
dermatitis, Stevens-Johnson syndrome, epidermal
necrolysis
36Sulfonamides Adverse Effects (contd)
- Body System Adverse Effects
- GI Nausea, vomiting, diarrhea, pancreatitis
- Other Convulsions, crystalluria, toxic
nephrosis, headache, peripheral neuritis,
urticaria - http//www.youtube.com/watch?vifQMm2xuyqcplaynex
t1listPL27024F7449C9E999featureresults_main
37Beta-Lactam Antibiotics
- Penicillins
- Cephalosporins
- Carbapenems
- Monobactams
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39Penicillins
- First introduced in the 1940s
- Bactericidal inhibit cell wall synthesis
- Kill a wide variety of bacteria
- Bacteria produce enzymes capable of destroying
penicillins - These enzymes are known as beta-lactamases
- As a result, the medication is not effective
40Penicillins
- Natural penicillins
- Penicillinase-resistant penicillins
- Aminopenicillins
- Extended-spectrum penicillins
41Penicillins (contd)
- Natural penicillins
- penicillin G, penicillin V potassium
- Penicillinase-resistant drugs
- cloxacillin, dicloxacillin, nafcillin, oxacillin
42Penicillins (contd)
- Aminopenicillins
- amoxicillin, ampicillin
- Extended-spectrum drugs
- piperacillin, ticarcillin, carbenicillin
- Usually used with other drugs rarely used alone
43Penicillins (contd)
- Chemicals have been developed to inhibit these
enzymes - Clavulanic acid
- Tazobactam
- Sulbactam
- These chemicals bind with beta-lactamase and
prevent the enzyme from breaking down the
penicillin, thus making the drug more effective
44Penicillins (contd)
- Penicillinbeta-lactamase inhibitor combination
drugs - Ampicillin sulbactam Unasyn
- Amoxicillin clavulanic acid Augmentin
- Ticarcillin clavulanic acid Timentin
- Piperacillin tazobactam Zosyn
45Penicillins Indications
- Prevention and treatment of infections caused by
susceptible bacteria, such as - Gram-positive bacteria
- Streptococcus, Enterococcus, Staphylococcus
46Penicillins Adverse Effects
- Allergic reactions occur in 0.7 to 4 of cases
- Urticaria, pruritus, angioedema
- Those allergic to penicillins have a fourfold to
sixfold increased risk of allergy to other
beta-lactam antibiotics - Cross-sensitivity between penicillins and
cephalosporins is between 1 and 4
47Penicillins Adverse Effects (contd)
- Common adverse effects
- Nausea, vomiting, diarrhea, abdominal pain
- Other adverse effects are less common
48Penicillins Interactions
- MANY interactions!
- NSAIDs
- Oral contraceptives Decreases effectiveness
- Warfarin Enhanced anticoagulant effect r/t
decrease in intestinal flora producing vitamin K - Others
49MRSA
- METHICILLIN RESISTANT STAPHYLOCOCCUS AUREUS
- Hand washing and gloving
- Goal is to avoid healthcare associated infections
- Colonized means harbors the bacterial infection
50NURSING CONSIDERATIONSFOR PENICILLIN
- Take with a full glass of water
- Do not skip doses
- Take all of the medication as prescribed
- Notify MD of adverse reactions
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52Cephalosporins
- First generation
- Second generation
- Third generation
- Fourth generation
- Fifth generation (not yet marketed)
53Cephalosporins (contd)
- Semisynthetic derivatives
- Structurally and pharmacologically related to
penicillins - Bactericidal action
- Broad spectrum
- Divided into groups according to their
antimicrobial activity
54Cephalosporins First Generation
- Good gram-positive coverage
- Poor gram-negative coverage
- Parenteral and PO forms
- Examples
- cefadroxil
- cephradine
- cefazolin
- cephalexin
55Cephalosporins First Generation (contd)
- Used for surgical prophylaxis, and for
susceptible staphylococcal infections - cefazolin (Ancef and Kefzol) IV or IM
- cephalexin (Keflex) PO
-
56Cephalosporins Second Generation
- Good gram-positive coverage
- Better gram-negative coverage than first
generation - Examples
- cefaclor
- cefprozil
- cefoxitin
- cefuroxime
- loracarbef
- cefotetan
-
-
57Cephalosporins Second Generation (contd)
- cefoxitin (Mefoxin) IV and IM
- Used prophylactically for abdominal or colorectal
surgeries - Also kills anaerobes
- cefuroxime
- Zinacef is parenteral form Ceftin is PO
- Surgical prophylaxis
- Does not kill anaerobes
58Cephalosporins Third Generation
- Most potent group against gram-negative bacteria
- Less active against gram-positive bacteria
- Examples
- ceftibuten
- cefotaxime
- ceftazidime
- cefdinir
- ceftizoxime
- ceftriaxone
- ceftazidime
-
59Cephalosporins Third Generation (contd)
- ceftriaxone (Rocephin)
- IV and IM, long half-life, once-a-day dosing
- Elimination is primarily hepatic
- Easily passes meninges and diffused into CSF to
treat CNS infections
60Cephalosporins Third Generation (contd)
- ceftazidime (Ceptaz)
- IV and IM forms
- Excellent gram-negative coverage
- Used for difficult-to-treat organisms such as
Pseudomonas - Eliminated by renal instead of biliary route
- Excellent spectrum of coverage
- Resistance is limiting usefulness
61Cephalosporins Fourth Generation
- Broader spectrum of antibacterial activity than
third generation, especially against
gram-positive bacteria - Uncomplicated and complicated UTI
- cefepime (Maxipime)
62Cephalosporins Fifth Generation
- Ceftobipriole (not available)
- Broader spectrum of antibacterial activity
- Effective against a wide variety of organisms
- MRSA
- Pseudomonas
63Cephalosporins Adverse Effects
- Similar to penicillins
- Mild diarrhea, abdominal cramps, rash, pruritus,
redness, edema - Potential cross-sensitivity with penicillins if
allergies exist
64Carbapenems
- Very broad-spectrum antibacterial action
- Reserved for complicated body cavity and
connective tissue infections - May cause drug-induced seizure activity
- This risk can be reduced with proper dosage
- All given parenterally
65Carbapenems
- imipenem/cilastatin (Primaxin)
- Used for treatment of bone, joint, skin, and
soft-tissue infections many other uses - Cilastatin inhibits an enzyme that breaks down
imipenem - meropenem (Merrem)
- ertapenem (Invanz)
- doripenem (Doribax)
66Monobactams
- Aztreonem (Azactam) Only drug in this catagory
- Beta-lactam antibiotic
- Gram negative bacteria
- Inhibits cell wall synthesis
- Common adverse effects
67Macrolides
- erythromycin (E-mycin, E.E.S, others)
- azithromycin (Zithromax)
- Z-Pack 3 5 day dose pack
- clarithromycin (Biaxin)
- dirithromycin
- http//www.youtube.com/watch?v2g-2oLb0IQwfeature
related
68MacrolidesMechanism of Action
- Prevent protein synthesis within bacterial cells
- Considered bacteriostatic
- Bacteria will eventually die
- In high enough concentrations, may also be
bactericidal
69Macrolides Indications
- Strep infections
- Streptococcus pyogenes
- (group A beta-hemolytic streptococci)
- Mild to moderate URI and LRI
- Haemophilus influenzae
- Spirochetal infections
- Syphilis and Lyme disease
- Gonorrhea, Chlamydia, Mycoplasma
70Macrolides Indications (contd)
- azithromycin and clarithromycin
- Recently approved for mycobacterium avium-
- intracellular complex infection (opportunistic
- infection associated with HIV/AIDS)
- clarithromycin
- Recently approved for use in combination with
omeprazole for treatment of active ulcer disease
associated with Helicobacter pylori infection
71Macrolides Indications (contd)
- Fidaxomicin (Dificid)
- Treatment of Clostridium difficile-associated
diarrhea in adults 18 years of age. - Following oral administration, only minimal
systemic absorption occurs remains mainly
confined to and acts locally in the GI tract.
72Macrolides Adverse Effects
- GI effects, primarily with erythromycin
- Nausea, vomiting, diarrhea, hepatotoxicity,
flatulence, jaundice, anorexia - Newer drugs, azithromycin and clarithromycin
fewer GI adverse effects, longer duration of
action, better efficacy, better tissue penetration
73Ketolide
- telithromycin (Ketek)
- Only drug in this class
- Better antibacterial coverage than macrolides
- Active against gram-positive bacteria, including
multidrug-resistant strains of S. pneumoniae - Associated with severe liver disease
- Use is limited
74Tetracyclines
- demeclocycline (Declomycin)
- oxytetracycline
- tetracycline
- doxycycline (Doryx, Vibramycin)
- minocycline
- tigecycline (Tygacil)
75Tetracyclines (contd)
- Natural and semisynthetic
- Obtained from cultures of Streptomyces
- Bacteriostaticinhibit bacterial growth
- Inhibit protein synthesis
- Stop many essential functions of the bacteria
76Tetracyclines Indications
- Broad spectrum
- Gram-negative and gram-positive organisms,
protozoa, Mycoplasma, Rickettsia, Chlamydia,
syphilis, Lyme disease, acne, others - Demeclocycline is also used to treat SIADH by
inhibiting the action of ADH
77Tetracyclines (contd)
- Bind (chelate) to Ca2 and Mg2 and Al3 ions to
form insoluble complexes - Thus, dairy products, antacids, and iron salts
reduce oral absorption of tetracyclines - Should not be used in children under age 8 or in
pregnant/lactating women because tooth
discoloration will occur if the drug binds to the
calcium in the teeth
78Tetracyclines Adverse Effects
- Strong affinity for calcium
- Discoloration of permanent teeth and tooth enamel
in fetuses and children, or nursing infants if
taken by the mother - May retard fetal skeletal development if taken
during pregnancy - http//www.youtube.com/watch?vAMAqU7MJ_sc
79Tetracyclines Adverse Effects (contd)
- Alteration in intestinal flora may result in
- Superinfection (overgrowth of nonsusceptible
organisms such as Candida) - Diarrhea
- Pseudomembranous colitis
80Tetracyclines Adverse Effects (contd)
- May also cause
- Vaginal candidiasis
- Gastric upset
- Enterocolitis
- Maculopapular rash
- Other effects
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82Antibiotic Therapy Toxicities
- Ototoxicity
- Temporary or permanent hearing loss, balance
problems - Nephrotoxicity
- Varying degrees of reduced renal function
- Rising serum creatinine may indicate reduced
creatinine clearance - Monitor trough levels every 5 to 7 days while on
therapy or as ordered - Monitor serum creatinine levels at least every 3
days as an index of renal function
83Aminoglycosides
- gentamicin (Garamycin)
- neomycin (Neo-fradin)
- tobramycin (Nebcin)
- amikacin (Amikin)
- kanamycin
- streptomycin
84Aminoglycosides (contd)
- Natural and semisynthetic
- Produced from Streptomyces
- Poor oral absorption no PO forms
- Very potent antibiotics with serious toxicities
- Bactericidal prevent protein synthesis
- Kill mostly gram-negative bacteria some
gram-positive also
85Aminoglycosides Indications
- Used to kill gram-negative bacteria such as
Pseudomonas, E. coli, Proteus, - Klebsiella, Serratia
- Often used in combination with other
- antibiotics for synergistic effects
- Used for certain gram-positive infections that
are resistant to other antibiotics
86Aminoglycosides Indications (contd)
- Aminoglycosides are poorly absorbed through the
GI tract, and given parenterally - Exception neomycin
- Given orally to decontaminate the GI tract before
surgical procedures - Also used as an enema for this purpose
87Aminoglycosides Adverse Effects
- Cause serious toxicities
- Nephrotoxicity (renal damage)
- Ototoxicity (auditory impairment and vestibular
impairment eighth cranial nerve) - Must monitor drug levels to prevent toxicities
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89Aminoglycosides Adverse Effects (contd)
- Ototoxicity and nephrotoxicity are
- the most significant
- Headache
- Paresthesia
- Fever
- Superinfections
- Vertigo
- Skin rash
- Dizziness
90Quinolones
- ciprofloxacin (Cipro)
- norfloxacin (Noroxin)
- levofloxacin (Levaquin)
- moxifloxacin (Avelox)
91Quinolones (contd)
- Also called fluoroquinolones
- Excellent oral absorption
- Absorption reduced by antacids
- Effective against gram-negative organisms and
some gram-positive organisms
92Quinolones Mechanism of Action
- Bactericidal
- Alter DNA of bacteria, causing death
- Do not affect human DNA
93Quinolones Indications
- Gram-negative bacteria such as pseudomonas
- Respiratory infections
- Bone and joint infections
- GI infections
- Skin infections
- Sexually transmitted diseases
- Anthrax
94Fluoroquinolones Adverse Effects
- Body System Adverse Effects
- CNS Headache, dizziness, fatigue, depression,
restlessness, insomnia - GI Nausea, vomiting, diarrhea, constipation,
thrush, increased liver function studies, others - Cardiac Prolonged QT interval
95Fluoroquinolones Adverse Effects (contd)
- Body System Adverse Effects
- Integumentary Rash, pruritus, urticaria,
flushing, photosensitivity (with lomefloxacin) - Other Fever, chills, blurred vision, tinnitus
- Black box warning increased risk of tendonitis
and tendon rupture
96Other Antibiotics
- clindamycin (Cleocin)
- linezolid (Zyvox)
- metronidazole (Flagyl)
- nitrofurantoin (Macrodantin)
- quinupristin and Dalfopristin (Synercid)
- daptomycin (Cubicin)
- vancomycin (Vancocin)
- colistimethate (Coly-mycin)
97Other Antibiotics (contd)
- clindamycin (Cleocin)
- Used for chronic bone infections, GU infections,
intra-abdominal infections, other serious
infections - May cause pseudomembranous colitis
98Other Antibiotics (contd)
- linezolid (Zyvox)
- New class oxazolidinones
- Used to treat vancomycin-resistant Enterococcus
faecium (VREF, VRE), hospital-acquired skin and
skin structure infections, including those with
MRSA - May cause hypotension, serotonin syndrome if
taken with SSRIs, and reactions if taken with
tyramine-containing foods
99Other Antibiotics (contd)
- metronidazole (Flagyl)
- Used for anaerobic organisms
- Intra-abdominal and gynecologic infections
- Protozoal infections
- Several drug interactions
100Other Antibiotics (contd)
- nitrofurantoin (Macrodantin)
- Primarily used for UTIs (E. coli, S. aureus,
Klebsiella , Enterobacter) - Use carefully if renal function is impaired
- Drug concentrates in the urine
- May cause fatal hepatotoxicity
- Usually well-tolerated if patient is kept
well-hydrated
101Other Antibiotics (contd)
- quinupristin and dalfopristin (Synercid)
- 3070 combination, work synergistically
- Used for bacteremia and infections caused by
vancomycin-resistant Enterococcus (VRE) and other
complicated skin infections - May cause arthralgias, myalgias
102Other Antibiotics (contd)
- daptomycin (Cubicin)
- New class lipopeptide
- Used to treat complicated skin and
- soft-tissue infections
103Other Antibiotics (contd)
- vancomycin (Vancocin)
- Natural, bactericidal antibiotic
- Destroys cell wall
- Treatment of choice for MRSA and other
- gram-positive infections
- Must monitor blood levels to ensure therapeutic
levels and prevent toxicity - May cause ototoxicity and nephrotoxicity
- Should be infused over 60 minutes
- Rapid infusions may cause hypotension
104Other Antibiotics (contd)
- vancomycin (Vancocin) (contd)
- Monitor IV site closely
- Red man syndrome may occur
- Flushing/itching of head, neck, face, upper trunk
- Antihistamine may be ordered to reduce these
effects - Ensure adequate hydration (2 L fluids/24 hr) if
not contraindicated to prevent nephrotoxicity - Monitor trough levels carefully
105Nursing Implications
- It is ESSENTIAL to obtain cultures from
appropriate sites BEFORE beginning antibiotic
therapy - Instruct patients to take antibiotics exactly as
prescribed and for the length of time prescribed
they should not stop taking the medication early
when they feel better
106Nursing Implications (contd)
- Aminoglycosides
- Monitor peak and trough blood levels of these
drugs to prevent nephrotoxicity and ototoxicity - Symptoms of ototoxicity include dizziness,
tinnitus, and hearing loss - Symptoms of nephrotoxicity include urinary casts,
proteinuria, and increased BUN and serum
creatinine levels
107ANTIVIRAL MEDICATIONS
108Understanding Viruses
- Viral replication
- A virus cannot replicate on its own
- It must attach to and enter a host cell
- It then uses the host cells energy to synthesize
protein, DNA, and RNA
109Understanding Viruses (contd)
- Viruses are difficult to kill because they live
inside the cells - Any drug that kills a virus may also kill
cells
110Viral Illnesses
- Most viral illnesses are bothersome, but
survivable - Effective vaccines have prevented some illnesses
- Effective drug therapy is available for a small
number of viral infections
111Antiviral Drugs
- Antiviral drugs kill or suppress the virus by
destroying virions or inhibiting ability to
replicate viruses controlled by current antiviral
therapy -
112Antiviral Drugs (contd)
- Viruses controlled by current antiviral therapy
- Cytomegalovirus (CMV)
- Hepatitis viruses
- Herpes viruses
- Human immunodeficiency virus (HIV)
- Influenza viruses (the flu)
- Respiratory syncytial virus (RSV)
113Antiviral Drugs (contd)
- Key characteristics of antiviral drugs
- Able to enter the cells infected with virus
- Interfere with viral nucleic acid synthesis
and/or regulation - Some drugs interfere with ability of virus to
bind to cells - Some drugs stimulate the bodys immune system
114Antiviral Drugs (contd)
- Opportunistic infections
- Occur in immunocompromised patients
- Would not normally harm an immunocompetent person
- Require long-term prophylaxis and
- antiinfective drug therapy
- Can be other viruses, fungi, bacteria, or
protozoa
115Antiviral Drugs (contd)
- Antiviral drugs
- Used to treat infections caused by viruses other
than HIV - Antiretroviral drugs
- Used to treat infections caused by HIV, the virus
that causes AIDS
116Virus Infections
- Herpes-simplex viruses
- HSV-1 (oral herpes)
- HSV-2 (genital herpes)
- Human herpesvirus/VZV
- Chickenpox and shingles (HHV-3 or VZV)
- Shingles
- http//www.youtube.com/watch?vMEvyptIJsuE
- Epstein-Barr (HHV-4)
- Cytomegalovirus (HHV-5)
- Kaposis sarcoma (HHV-8)
-
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120Antiviral Drugs (non-HIV)
- Mechanism of action
- Inhibit viral replication
- Used to treat non-HIV viral infections
- Influenza viruses
- HSV, VZV
- CMV
- Hepatitis A, B, C (HAV, HBV, HCV)
121Antiviral Drugs (non-HIV) (contd)
- Adverse effects
- Vary with each drug
- Healthy cells are often killed also, resulting in
serious toxicities
122Antiviral Drugs (non-HIV) (contd)
- amantadine (Symmetrel)
- Narrow antiviral spectrum active only against
influenza A - 2008 CDC guidelines do not recommend use for
treatment or prevention of flu - CNS effects insomnia, nervousness,
lightheadedness - GI effects anorexia, nausea, others
123Antiviral Drugs (non-HIV) (contd)
- rimantadine (Flumadine)
- Same spectrum of activity, mechanism of action,
and indications as amantadine - Fewer CNS adverse effects
- Causes GI upset
124Antiviral Drugs (non-HIV) (contd)
- acyclovir (Zovirax)
- Synthetic nucleoside analog
- Used to suppress replication of
- HSV-1, HSV-2, VZV
- Drug of choice for treatment of initial and
recurrent episodes of these infections - Oral, topical, parenteral forms
125Antiviral Drugs (non-HIV) (contd)
- ganciclovir (Cytovene)
- Synthetic nucleoside analog
- Used to treat infection with cytomegalovirus
(CMV) - Oral, parenteral forms
- CMV retinitis
- Ophthalmic form surgically implanted
- Ocular injection (fomivirsen)
126Antiviral Drugs (non-HIV) Dose-Limiting
Toxicities
- ganciclovir
- Bone marrow toxicity
- foscarnet and cidofovir
- Renal toxicity
127Antiviral Drugs (non-HIV) Neuraminidase
Inhibitors
- oseltamivir (Tamiflu) and zanamivir (Relenza)
- Active against influenza types A and B
- Reduce duration of illness
- Oseltamivir causes nausea and vomiting
- Zanamivir causes diarrhea, nausea, sinusitis
- Treatment should begin within 2 days of influenza
symptom onset
128Antiviral Drugs (non-HIV) Ribavirin
- Synthetic nucleoside analog
- Given orally, or oral or nasal inhalation
- Inhalation form (Virazole) used for hospitalized
infants with RSV infections
129HIV and AIDS
- Human immunodeficiency virus (HIV) infection and
acquired immune deficiency syndrome (AIDS) - ELISA (enzyme-linked immunosorbent assay)
- Detects HIV exposure based on presence of human
antibodies to the virus in the blood - Retrovirus
- Transmitted by sexual activity, intravenous drug
use, perinatally from mother to child
130Four Stages of HIV Infection
- Stage 1 asymptomatic infection
- Stage 2 early, general symptoms of disease
- Stage 3 moderate symptoms
- Stage 4 severe symptoms, often leading to death
- WHO model
131Opportunistic Infections
- Protozoal
- Toxoplasmosis of the brain, others
- Fungal
- Candidiasis of the lungs, esophagus, trachea
- Pneumocystis jirovecii pneumonia, others
- Viral
- CMV disease, HSV infection, others
132Opportunistic Infections (contd)
- Bacterial
- Various mycobacterial infections
- Extrapulmonary TB
- Opportunistic neoplasias
- Kaposis sarcoma, others
- HIV wasting syndrome
- Major weight loss, chronic diarrhea, chronic
fever
133Antiretroviral Drugs
- HAART
- Highly active antiretroviral therapy
- Includes at least three medications
- Cocktails
- These medications work in different ways to
reduce the viral load
134Antiretroviral Drugs (contd)
- Reverse transcriptase inhibitors (RTIs)
- Block activity of the enzyme reverse
transcriptase, preventing production of new viral
DNA - Protease inhibitors (PIs)
- Inhibit the protease retroviral enzyme,
preventing viral replication - Fusion inhibitors
- Inhibit viral fusion, preventing viral
replication - Entry inhibitor-CCR5 coreceptor antagonists
- HIV integrase strand transfer inhibitors
135Antiretroviral Drugs (contd)
- Reverse transcriptase inhibitors (RTIs)
- Nucleoside RTIs (NRTIs)
- Nonnucleoside RTIs (NNRTIs)
- Examples
- abacavir (Ziagen)
- delavirdine (Rescriptor)
- didanosine (Videx)
- lefavirenze (Sustiva)
136Antiretroviral Drugs (contd)
- zidovudine (Retrovir)
- First anti-HIV medication
- Nucleoside reverse transcriptase inhibitor
- Can be given to pregnant HIV-positive women and
newborn babies to prevent maternal transmission
of HIV - Major dose-limiting adverse effect bone marrow
suppression
137Antiretroviral Drugs (contd)
- Protease inhibitors (PIs)
- Inhibit the protease retroviral enzyme,
preventing viral replication - amprenavir (Agenerase)
- indinavir (Crixivan)
- nelfinavir (Viracept)
- ritonavir (Norvir)
-
138Antiretroviral Drugs (contd)
- Fusion inhibitors
- Inhibit viral fusion, preventing viral
replication - A newer class of antiretroviral drugs
- Example enfuvirtide (Fuzeon)
139Antiretroviral Drugs (contd)
- CCR5 antagonist
- maraviroc (Selzentry)
- HIV integrase strand transfer inhibitor
- raltegravir (Isentress)
140Antiretroviral Drugs (contd)
- Combinations of multiple antiretroviral
medications are common - Adverse effects vary with each drug and may be
severe monitor for dose-limiting toxicities - Monitor for signs of opportunistic diseases
141Nursing Implications
- Be sure to teach proper application technique for
ointments, aerosol powders, and so on - Emphasize hand washing before and after
administration of medications to prevent site
contamination and spread of infection - Instruct patients to wear a glove or finger cot
when applying ointments or solutions to affected
areas
142Antitubercular Drugs
143Antitubercular Drugs
- Tuberculosis (TB)
- Caused by Mycobacterium tuberculosis
- Antitubercular drugs treat all forms of
Mycobacterium
144Mycobacterium Infections
- Common infection sites
- Lung (primary site)
- Brain
- Bone
- Liver
- Kidney
145Mycobacterium Infections (contd)
- Aerobic bacillus
- Passed from infected
- Humans
- Cows (bovine) and birds (avian)
- Much less common
146Mycobacterium Infections (contd)
- Tubercle bacilli are conveyed by droplets
- Droplets are expelled by coughing or sneezing,
and then gain entry into the body by inhalation - Tubercle bacilli then spread to other body organs
via blood and lymphatic systems - Tubercle bacilli may become dormant, or walled
off by calcified or fibrous tissue
147Antitubercular Drugs
- First-line drugs
- isoniazid (INH)
- ethambutol
- rifampin
- rifabutin
- pyrazinamide (PZA)
- Rifapentine
- streptomycin
- Primary drug used
148Antitubercular Drugs (contd)
- Second-line drugs
- capreomycin
- amikacin
- cycloserine
- levofloxacin
- ethionamide
- ofloxacin
- kanamycin
- para-aminosalicyclic acid (PAS)
149Antitubercular Drug TherapyConsiderations
- Perform drug-susceptibility testing on the first
Mycobacterium that is isolated from a patient
specimen to prevent the development of MDR-TB - Even before the results of susceptibility tests
are known, begin a regimen with multiple
antitubercular drugs (to reduce chances of
development of resistance)
150Antitubercular Drug TherapyConsiderations
(contd)
- Adjust drug regimen once the results of
susceptibility testing are known - Monitor patient compliance closely during therapy
- Problems with successful therapy occur because of
patient nonadherence to drug therapy and the
increased incidence of drug-resistant organisms
151Antitubercular Therapy
- Effectiveness depends upon
- Type of infection
- Adequate dosing
- Sufficient duration of treatment
- Adherence to drug regimen
- Selection of an effective drug combination
152Antitubercular Therapy (contd)
- Problems
- Drug-resistant organisms
- Drug toxicity
- Patient nonadherence
- Multidrug-resistant TB (MDR-TB)
153Isoniazid (INH)
- Drug of choice for TB
- Resistant strains of Mycobacterium emerging
- Metabolized in the liver through
acetylationwatch for slow acetylators - Used alone or in combination with other drugs
- Contraindicated with liver disease
154Adverse Effects
- INH
- Peripheral neuropathy, hepatotoxicity
- ethambutol
- Retrobulbar neuritis, blindness
- rifampin
- Hepatitis discoloration of urine, stools, and
other body fluids
155Nursing Implications
- Perform liver function studies in patients who
are to receive isoniazid or rifampin (especially
in elderly patients or those who use alcohol
daily)
156Nursing Implications (contd)
- Patient education is critical
- Therapy may last for up to 24 months
- Take medications exactly as ordered, at the same
time every day - Emphasize the importance of strict adherence to
regimen for improvement of condition or cure
157Nursing Implications (contd)
- Remind patients that they are contagious during
the initial period of their illnessinstruct in
proper hygiene and prevention of the spread of
infected droplets - Teach patients to take care of themselves,
including adequate nutrition and rest
158Nursing Implications (contd)
- Patients should not consume alcohol while on
these medications or take other medications,
including over-the-counter medications, unless
they check with their physician - Rifampin causes oral contraceptives to become
ineffective another form of birth control will
be needed
159Nursing Implications (contd)
- Patients who are taking rifampin should be told
that their urine, stool, saliva, sputum, sweat,
or tears may become reddish orange even contact
lenses may be stained - Pyridoxine may be needed to combat neurologic
adverse effects associated with INH therapy - Oral preparations may be given with meals to
reduce GI upset, even though recommendations are
to take them 1 hour before or 2 hours after meals
160Nursing Implications (contd)
- COMPLIANCE AND DOT THERAPY
- Because of the length of treatment, it is
difficult to be sure patient will comply - Family education may improve compliance
- DOT DIRECT OBSERVATION THERAPY
161Antifungal Drugs
162Indications
- Systemic and topical fungal infections
- Drug of choice for the treatment of many severe
systemic fungal infections is amphotericin B - Choice of drug depends on type and location of
infection
163Adverse Effects Amphotericin B
- Fever
- Chills
- Cardiac dysrhythmias
- Nausea and GI upset
- Renal toxicity
- Headache
- Malaise
- Hypotension
- Tingling, numbness in hands and feet
- Lowered potassium and magnesium levels
164Adverse Effects Amphotericin B(contd)
- Main concerns
- Renal toxicity
- Neurotoxicity seizures and paresthesias
- Many other adverse effects
165Nursing Implications (contd)
- amphotericin B
- To reduce the severity of the infusion-related
reactions, pretreatment with an antipyretic
(acetaminophen), antihistamines, antiemetics, and
corticosteroids may be given - Use an IV infusion pump