Pharmacology CH 86
Clindamycin
"Other" Bacteriostatic Inhibitor of Protein Synthesis Effective against anaerobic and gram + aerobic organisms Biggest risk is AAPMC -- C.difficile -- WATCH FOR SYMPTOMS OF DIARRHEA ** Rapid IV infusion -- Cardiac arrest risk
erythromycin
Adverse Effects for ___________ ** GI UPSET - Affects the motility of the GI tract (motilin)- used with diabetic gastroparesis; passing feeding tubes - helps place small bore feeding tubes QT prolongation and cardiac death! - avoid if already have dysrhythmia Drug-drug interactions-CYP3A4 - Ex: Some HIV drugs, Antifungal drugs Hearing loss with high doses = ototoxicity Suprainfection
food
As a rule, _____ reduces the absorption of erythromycin base and erythromycin stearate (2 of the 3 oral forms)
azithromycin
Macrolide (Z-pack) -- Take pills 3-5 days - increases compliance -- able to keep working even after completion of ABT
renal impairment
Tetracyclines can cause fatty infiltration of the liver and may exacerbate _______ ________ in patients with preexisting kidney disease
tetracycline
____________ Treats: RMSF, typhus, cholera, Lyme disease, H.pylori, chlamydia (and other STIs), acne
4 (Tetracycline is contraindicated in children younger than 8 years of age, because it binds to calcium in developing teeth, resulting in permanent discoloration of the teeth. Delay in long bone growth, early onset of puberty, and severe face and body acne are not adverse effects associated with tetracyclines.)
A nurse assessing a patient who is 12 years old should associate which complication with the patient's receiving tetracycline as a younger child? 1 Delay in long bone growth 2 Early onset of puberty 3 Severe face and body acne 4 Discoloration of the teeth
1 (Linezolid can cause reversible myelosuppression, manifesting as anemia, leukopenia, or even pancytopenia. The potassium and blood glucose levels are not affected by linezolid.)
A patient who has a vancomycin-resistant enterococci (VRE) infection is receiving linezolid [Zyvox]. Which laboratory result indicates that the patient is having an adverse effect? 1 White blood cell (WBC) count of 1200 units/L 2 Hemoglobin (Hgb) level of 18 g/dL 3 Potassium level of 3.0 mEq/dL 4 Glucose level of 200 mg/dL
tetracyclines
Adverse Effects of ___________: Nausea, vomiting, diarrhea - really bad with these - though technically should be given on empty stomach, most people eat with food d/t GI distress Photosensitivity - limit sun exposure, wear sunscreen Yellow-brown discoloration of teeth (under 8) - children should not be given, discoloration is permanent Do not give to pregnant women either Suprainfection common- Hepatotoxicity Renal toxicity
macrolides
Broad spectrum gram + and gram - MOA: Bacteriostatic inhibit protein synthesis Prototype: erythromycin (E-mycin) Examples: Clarithromycin (Biaxin) Azithromycin (Z-pack) -
theophylline, carbamazepine, warfarin
Erythromycin can increase the plasma levels and half lives of several drugs by: - inhibiting hepatic cytochrome P450 drug metabolizing enzymes - Elevated levels are a concern with: 1. _______ (used for asthma) 2. _______ (used for seizures and bipolar) 3. _______ (anticoagulant)
antagonist
Erythromycin is an _____ to chloramphenicol and clindamycin by preventing binding to bacterial ribosomes - do not use concurrently
azithromycin
Like erythromycine, __________ has the potential to cause prolonged QT interval - those at highest risk are: - preexisting prolonged QT interval - low blood levels of potassium or magnesium - slower than normal heart rate - those who use drugs to treat abnormal heart rhythms
Tetracyclines
MOA: Bacteriostatic Inhibit bacterial protein synthesis Activity: Broad spectrum Gram positive and gram negative and some protozoa Widespread use --> resistance Treats: RMSF, typhus, cholera, Lyme disease, H.pylori, chlamydia, acne
erythromycin
Macrolide Prototype : __________ - relatively broad spectrum - bacteriostatic (but can be bactericidal) - active against most gram + and some gram - - Preferred treatment for pneumonia caused by Legionella pneumophila - Preferred tx for whooping cough (pertussis) and acute diphtheria
linezolid (Zyvox)
New class of antibiotics = oxazolidinone abx MOA: bacteriostatic inhibitor of protein synthesis Effective against -- MRSA - used IF vancomycin does not work -- VRE Adverse Effect -- myelosuppression - affecting bone marrow -- low WBC, platelets, RBC -- Should not be given to patients on SSRI antidepressants (serotonin syndrome)
AAPC (Antibiotic-Associated Pseudomembranous Colitis)
Suprainfection -- C.difficile Symptoms: profuse (ongoing, VERY FREQUENT), watery diarrhea, abdominal pain, fever Stool specimen x 3 leukocytosis Can be fatal Contact precautions Handwashing Only - no hand rub
tetracyclines, fluoroquinolones
Teaching for __________ and _____________ -- Calcium, Iron, Mg, Al decrease drug absorption by 50%. -- (1-3 hours separation between when take the drug and if consume any of these products) -- Avoid antacids, anti-diarrheal, dairy products
GI
Tetraccyclines irritate the _______ system: so oral therapy is frequently associated with: - epigastric burning - cramps - nausea - vomiting - diarrhea
bacteriostatic, protein synthesis
Tetracyclines are _______ and inhibit _______ ________
calcium
Tetracyclines bind to _____ in developing teeth - resulting in yellow or brown discoloration - hypoplasia of enamel may also occur - Discoloration of teeth occurs when they are taken by patients age 4 mon to 8 years
3 (Tigecycline is the first representative of a new class of antibiotics, the glycyclines. It is a tetracycline derivative made to overcome drug resistance and is active against many drug-resistant strains. It has adverse effects similar to those of the tetracyclines.)
The nurse identifies tigecycline [Tygacil] as a derivative of what? 1 Penicillins 2 Cephalosporins 3 Tetracyclines 4 Macrolides
1 (Generic tetracycline is a short-acting tetracycline. Declomycin is an intermediate-acting tetracycline, and Vibramycin and Minocin are long-acting tetracyclines.)
The nurse identifies which drug as a short-acting tetracycline? 1 Tetracycline (generic) 2 Declomycin 3 Vibramycin 4 Minocin
1, 2, 3 (Nausea and vomiting may occur. The patient should not stop taking the medication; rather, the healthcare provider should be notified so that an alternative plan can be discussed. The other three instructions should be included in the patient teaching.)
The nurse should include which instructions when teaching a patient about tigecycline therapy? (Select all that apply.) 1 "Use sunscreen when you are outside." 2 "If you have diarrhea more than five times a day, notify your healthcare provider." 3 "Avoid using this drug if you are pregnant." 4 "Stop taking the drug if you experience nausea." 5 "Stop taking the drug if you experience vomiting."
2 (Clostridium difficile-associated diarrhea (CDAD) is the most severe toxicity associated with clindamycin and is characterized by profuse, watery stools. The cause is superinfection of the bowel with Clostridium difficile, an anaerobic gram-positive bacillus. Gray syndrome, which usually occurs in infants and those with aplastic anemia, is an adverse effect of chloramphenicol [Chloromycetin]. Hepatotoxicity is associated most closely with telithromycin [Ketek].)
What does the nurse identify as an adverse effect of clindamycin [Cleocin] therapy? 1 Cyanosis and gray discoloration of the skin 2 Frequent loose, watery stools with mucus and blood 3 Reduction in all blood cells produced in the bone marrow 4 Elevated bilirubin, with dark urine and jaundice
QT interval
When present in high concentrations, erythromycin can prolong the _____ _______ - thereby posing a risk of torsades de pointes - potentially fatal ventricular dysrhythmia.
2 (When present in high levels, erythromycin can prolong the QT interval, causing a potentially fatal ventricular dysrhythmia. It should be avoided by patients taking class IA or class III antidysrhythmic medications or others that inhibit metabolism.)
Which cardiovascular finding does the nurse identify as a possible adverse effect of erythromycin [Ery-Tab] therapy? 1 Heart rate of 52 beats per minute 2 Prolonged QT interval 3 Jugular vein distention 4 Grade III diastolic murmur
2 (Tetracyclines are bacteriostatic antibiotics; photosensitivity and severe sunburn are common adverse effects. A full course of antibiotics must always be taken. Blood studies are not necessary for therapeutic levels. Absorption decreases after ingestion of chelates, such as calcium and magnesium, so doses should be given 2 hours before or 2 hours after ingestion of milk products.)
Which instruction should a nurse include in the discharge teaching for a patient who is to start taking tetracycline? 1 "You may stop taking the pills when you begin to feel better." 2 "Use sunscreen and protective clothing when outdoors." 3 "You'll have to come back to the clinic for weekly blood work." 4 "Take the medication with yogurt or milk so you won't have nausea."
4 (Clarithromycin is a macrolide similar to erythromycin and can inhibit hepatic metabolism of medications such as warfarin and theophylline. The INR is the blood test used to evaluate warfarin ranges. The aPTT is the blood test used in monitoring heparin. The platelet count and ESR are not affected by clarithromycin.)
Which laboratory result should a nurse monitor more frequently when a patient is receiving clarithromycin [Biaxin] and warfarin [Coumadin]? 1 Activated partial thromboplastin time (aPTT) 2 Platelet count 3 Erythrocyte sedimentation rate (ESR) 4 International normalized ratio (INR)
2, 3, 5 (CDAD is a potentially fatal condition in which patients experience abdominal pain. If CDAD develops, clindamycin therapy should be stopped and vancomycin or metronidazole therapy started. Leukocytosis, not leukopenia, develops. Anticholinergics can make the diarrhea worse and therefore should be avoided.)
Which statements about CDAD associated with clindamycin therapy does the nurse identify as true? (Select all that apply.) 1 Leukopenia commonly occurs. 2 It is a potentially fatal condition. 3 Patients usually experience abdominal pain. 4 Anticholinergics are effective in treating the diarrhea. 5 Clindamycin therapy should be discontinued and vancomycin started.
GI disturbances
_______ _________ are the most common adverse effects of erythromycin - can be reduced by administering with meals
therapeutic uses
________ ______ of tetracyclines: 1. Infections diseases - rickettsial diseases - chlamydia - brucellosis - cholera - mycoplasma pneumoniae - lyme disease - anthrax - H. pylori infection 2. Acne - used topically and orally 3. Peptic Ulcer Disease - used in combo with metronidazole and bismuth subsalicylate 4. Peridontal disease 5. Rheumatoid arthritis
clindamycin
________ can promote severe CDAD - so indications are limited: - certain anaerobic infections outside of CNS - active against anaerobic and gram positive - Usually bacteriostatic
clindamycin
________ is the drug of choice for: - severe group A streptococcal infection - gas gangrene (rapidly suppresses synthesis of bacterial toxins) - abdominal and pelvic infections caused by Bacteroids fragilis
Linezolid
_________ is a first in class oxazolidinone antibiotic - has activity against multdrug-resistant gram positive pathogens including VRE and MRSA (has 5 approved indications) - Most common SE: diarrhea, nausea, headache - can cause reversible myelosuppression - anemia, leukopenia, thrombocytopenia, or even pancytopenia - taking it longer than 5 months has caused reversible optic neuropathy and irreversible peripheral neuropathy
tetracyclines
__________ are: - Broad spectrum - Bacteriostatic - 4 available: tetracycline, demeclocycline, doxycycline, minocycline - MOA: suppress bacterial growth by inhibiting protein synthesis - poor ability to cross mammalian cell membranes ** Typically used as second line of treatment
Tetracyclines
__________ must NOT be administered with: - calcium supplements - milk products - iron supplements - magnesium-containing laxatives - or most antacids d/t forming insoluble chelates