Antibiotics Affecting Protein Synthesis (Pharmacology Ch 45) Flashcards Preview

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Antibiotics affecting protein synthesis may be_____ or_______.
Uses include:

-bacteriostatic (such as tetracyclines and macrolides)
-bactericidal (such as aminoglycosides)
-Infections of the respiratory, GI, urinary, and reproductive tract and infections caused by rickettsia



-broad-spectrum antibiotics that inhibit micro-organism growth by preventing protein synthesis (bacteriostatic)
-select prototype medication = tetracycline (Sumycin)
-other medications: doxycycline (Vibramycin), minocycline (Minocin), demeclocycline (Declomycin)


Tetracyclines: therapeutic uses

1) administered topically and orally to treat acne vulgaris and topically for periodontal disease.
2) used as 1st line medication for:
-rickettsial infections (typhus fever, Rocky Mountain spotted fever)
-infections of urethra or cervix caused by Chlamydia trachomatis
-pneumonia caused by Mycoplasma pneumonia
-Lyme disease
-GI infections caused by Helicobacter pylori


adverse effects and nursing interventions/client education

1) GI discomfort (cramping, nausea, vomiting, diarrhea, and esophageal ulceration)--monitor clients for N, V, and D; monitor client's I&O; doxycycline and minocycline may be take w/ meals; avoid taking @ bedtime to reduce esophageal ulceration
2) yellow/brown tooth discoloration and/or hypoplasia of tooth enamel--avoid administration to children < 8 yrs or to pregnant women
3) hepatotoxicity (lethargy, jaundice)--avoid administration of high daily doses IV
4) photosensitivity (exaggerated sunburn)--advise clients to take precautions when out in sun
5) suprainfection of the bowel: antibiotic-associated pseudomembranous colitis (diarrhea, yeast infections of mouth, pharynx, vagina, bowels)--instruct clients to notify provider if diarrhea occurs
6) dizziness, lightheadedness, w/ minocycline--instruct clients to take care w/ ambulation and report these findings if they occur


Tetracyclines: contraindications/precautions

1) pregnancy risk category D
2) use during pregnancy after 4th month can cause staining of the deciduous teeth, but will not have permanent effect on permanent teeth.
*should not be given to young children and pregnant women
3) use cautiously in clients w/ liver and renal disease.
*doxycycline and minocycline may be used in clients who have renal disease


Tetracyclines: interactions

1) interaction w/ milk products, calcium or iron supplements, laxatives containing magnesium (magnesium hydroxide (Milk of Magnesia)), and antacids causes formation of nonabsorbable chelates, thus reducing absorption of tetracycline--should be taken on empty stomach with full glass of water; minocycline may be taken w/ meals; administer 1 hr before or 2 hr after taking food and supplements containing calcium and magnesium
2) tetracycline decreases efficacy of oral contraceptives--advise clients to use alternative form of birth control
3) both minocycline and doxycycline increase risk of digoxin toxicity--monitor digoxin level carefully if taken concurrently



-erythromycin slows growth of micro-organisms by inhibiting protein synthesis (bacteriostatic) but can be bactericidal if given for susceptible bacteria at high enough doses.
-select prototype medication = erythromycin (E-Mycin)
-other medications = azithromycin (Zithromax)


Macrolides: therapeutic uses

1) used for clients who have penicillin allergy, such as prophylaxis against rheumatic fever and bacterial endocarditis
2) used for Legionnaires' disease, whooping cough (pertussis), and acute diphtheria (eliminates the carrier state of diphtheria)
3) used for chlamydia infections (urethritis and cervicitis; pneumonia caused by Mycoplasma pneumoniae; respiratory tract infections caused by Streptococcus pneumoniae, and group A Streptococcus pyogenes)


adverse effects and nursing interventions/client education

1) GI discomfort (N, V, epigastric pain)--administer erythromycin w/ meals; observe for GI symptoms and notify provider
2) prolonged QT interval causing dysrhythmias and possible sudden cardiac death--use in clients with prolonged QT intervals is not recommended; avoid concurrent use w/ meds that affect hepatic drug metabolizing enzymes
3) ototoxicity w/ high-dose therapy--monitor for hearing loss, vertigo, and ringing in ear. Notify provider if occur.


Macrolides: contraindications/precautions

1) contraindicated in clients who have pre-existing liver disease, or existing QT prolongation


Macrolides: interactions

1) erythromycin inhibits metabolism of antihistamines theophylline, carbamazepine, warfarin, and digoxin, which can lead to toxicity of these meds--avoid using erythromycin w/ these meds if possible. If the must be used concurrently, monitor carefully for toxicity
2) verapamil and diltiazem, HIV protease inhibitors, antifungal medications, and nefazodone inhibit hepatic drug-metabolizing enzymes, which can lead to erythromycin-toxicity, causing a tachydysrhythmia and possible cardiac arrest--concurrent use is not recommended



-bactericidal antibiotics that destroy micro-organisms by disrupting protein synthesis
-select prototype medication = gentamicin
-other medications = amikacin (Amikin), tobramycin, neomycin (Mycifradin), streptomycin, and paromomycin (oral)


Aminoglycosides: therapeutic uses

1) medication of choice against aerobic gram-negative bacilli (Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, and Pseudomonas aeruginosa)
2) Paromomycin (oral) used for intestinal amebiasis and tapeworm infections
3) oral neomycin often used prior to surgery of GI tract to suppress normal flora, and topically to treat infections of eye, ear, skin
4) streptomycin used, along w/ other meds, to treat active TB and a variety of other serious infections caused by gram-positive, gram-negative, and acid-fast bacteria.


adverse effects and nursing interventions/client education

1) ototoxicity-cochlear damage (hearing loss) and vestibular damage (loss of balance)--monitor for tinnitus (ringing in the ear), headache, hearing loss, nausea, dizziness, vertigo; instruct clients to notify provider if tinnitus, hearing loss, or headaches occur; STOP aminoglycoside if manifestations occur.
2) nephrotoxicity r/t high total cumulative dose resulting in acute tubular necrosis (proteinuria, casts in urine, dilute urine, elevated BUN, creatinine levels)--monitor I&O, BUN, and creatinine levels; report hematuria and/or cloudy urine
3) intensified neuromuscular blockade resulting in respiratory depression or muscle weakness--closely monitor use in clients w/ myasthenia gravis, clients taking skeletal muscle relaxants, and those receiving general anesthetics
4) hypersensitivity (rash, pruritis, paresthesia of hands and feet, urticaria)--monitor clients for allergic reactions


adverse effects and nursing interventions/client education

1) neurologic disorder (peripheral neuritis, optic nerve dysfunction, tingling/numbness of hands and feet)--instruct clients to promptly report any manifestations to provider


Aminoglycosides: contraindications/precautions

1) use cautiously in those who have kidney impairment, pre-existing hearing loss, or myasthenia gravis
2) use cautiously in those taking ethacrynic acid (increases risk for ototoxicity), amphotericin B, cephalosporins, vancomycin (increases risk for nephrotoxicity), and neuromuscular blocking agents such as tubocurarine
3) clients with kidney impairment should receive reduced doses of amnoglycosides


Aminoglycosides: interactions

1) penicillin will inactivate aminoglycosides when mixed in same IV solution--DO NOT mix aminoglycosides and penicillins in the same IV solution
2) When administered concurrently w/ other ototoxic medications (loop diuretics), risk for ototoxicity greatly increases--assess frequently for hearing loss w/ concurrent med use


Aminoglycosides: nursing administration

1) most (gentamicin and amikacin) are administered only by IM or IV routes. Others (neomycin) can be administered orally or topically
2) measure aminoglycoside levels based on dosing schedules
-once-a-day dosing: only trough level needs to be measured
-divided doses:
-peak; 30 min after administration of aminoglycoside IM or 30 min after IV infusion has finished
-trough: right before next dose