Antibiotic Review

Antibiotic Review


General antibiotic review of common antibiotics: Penicillins, Tetracyclines, Macrolides, Fluoroquinolones, Sulfonamides, Aminoglycosides, & Neomycin



Penicillins (beta-lactams)

  • Drug of choice for group A Strep
  • B-Lactam Antibiotic
  • Bactericidal
  • MRSA is resistant to all PCN’s
  • Used for infections caused by aerobic, Gram + organisms
  • Narrow Spectrum penicillin (Gram +) = Penicillin G
  • Extended Spectrum penicillin (GRAM +, SOME GRAM-)= AMOXICILLIN, AMPICILLIN
  • Penicillin+ B-Lactamase inhibitor= AUGMENTIN
  • Renal adjustment needed
  • Beta-lactams are the preferred drug for most people due to high efficacy and cidal nature
  • Common side effects are: anaphylaxis (occurs infrequently), seizures (large doses), electrolyte disturbances, diarrhea


Aminopenicillins (Ampicillin (IV), Amoxicillin(PO)

  • Amoxicillin is the best-absorbed Beta lactam
  • Drug of choice for Enterococcal infections if susceptible
  • Covers some Gram + (Strep, Enterococcus, Listeria) but not MSSA, and limited Gram – coverage
  • Used for: Upper respiratory infections, sinusitis, otitis media, cellulitis, Listeria infections, UTI’s, early Lyme Disease (as alternative to Doxycycline)


Anti-Staphylococcal Penicillins (Methicillin, Nafcillin, Oxacillin (IV), Dicloxacillin (PO)

  • Drug of choice for MSSA infections
  • No MRSA coverage
  • For serious MSSA infections, Anti-Staphylococcal infections must be administered intravenously


Anti-Pseudomonal Penicillins (Piperacillin, Ticarcillin)

  • Usually combined beta lactamase inhibitors for broader coverage
  • If patient only has Pseudomonas, a beta lactamase inhibitor is not needed


Combined Penicillin/ Beta-Lactamase Inhibitors

  • Amoxicillin/Clavulanate (Augmentin)- PO
  • Broad spectrum with some Gram + (MSSA, Strep), some Gram – & anaerobes
  • No Pseudomonal activity
  • Used for: Sinusitis, respiratory infections, otitis media, skin infections (bite wounds).
  • Ampicillin/Sulbactam (Unasyn)- IV
  • Similar to Augmentin, except has activity against most Acinetobacter
  • Used for: Same as Augmentin but when IV administration is more effective
  • Piperacillin/Tazobactam (Zosyn)- IV
  • Covers Gram -, Gram +, Anaerobic coverage, Pseudomonas, and most SPICA A organisms
  • Better Gram – coverage than Unasyn
  • Has a higher dosage for Pseudomonas coverage: 4.5 g Q 6 HRS
  • Requires extended infusion- 3.375 g over 4 hours


Ticarcillin/Clavulanate (Timentin) IV

  • Coverage is similar to Zosyn and also covers Stenotrophomonas


Penicillin Key Notes

  • A major limitation of Penicillins is microbial resistance
  • Staphylococcus aureus is a major resistant organism to PCN
  • Methicillin-resistant Staphylococcus aures (MRSA) is now resistant to most antibiotics & difficult to treat
  • Penicillins are used as a first-choice empirical treatment for many infections
  • Penicillin G (IM) remains the drug of choice for Syphillis
  • The drug of choice for acute pharyngitis is Penicillin
  • Clinicians must be aware of the limitations of cephalosporin effectiveness.
  • Cephalosporins do not exhibit activity against a number of common organisms, including penicillin-resistant Pneumococcus, methicillin-resistant Staphylococcus aureus (MRSA) and staphylococcus epidermidis.



  • Products have triggered seizures in some patients.
  • Coagulation abnormalities have been reported with moxalactam, cefamandole, cefoperazone, ceftriaxone, and cefotetan.
  • Pseudomembranous colitis may occur because of Clostridium difficile.
  • Renal function impairment: Products may be nephrotoxic; use with caution in patients with renal impairment.
  • Hepatic function impairment: Cefoperazone is excreted in bile. Half-life is increased in hepatic disease.




  • Acute exacerbation of COPD
  • Sinusitis
  • Pneumonia
  • Chlamydia
  • Rickettsial infections
  • UTIs
  • The two tetracyclines seen in primary care are tetracycline and doxycycline. Doxycycline is by far the most commonly used tetracycline
  • Tetracyclines are active against a wide range of aerobic and gram-positive and gram-negative bacteria. Most gram-positive bacteria are now resistant to tetracyclines. These are not the drugs of choice for Streptococcus or Staphylococcus.
  • Their greatest usefulness is against rickettsia, mycoplasma, protozoa, and chlamydia.
  • Tetracyclines are not active against fungi or viruses.
  • Another major restriction is the contraindication for use in children younger than 8 years old and in pregnant women. If used in children or in pregnant women, the drug may permanently stain teeth.
  • They are one of the drugs of first choice for acute bacterial exacerbation of COPD, chlamydia, and rickettsial infections.
  • Doxycycline and minocycline are the two most commonly used tetracyclines. Most tetracyclines must not be taken with milk or antacids.


Long-term Usage of Tetracyclines

  • Obtain baseline tests for renal, hepatic function, and CBC every 3 months for patients on long-term therapy. May cause increased AST, ALT, serum alkaline phosphatase, bilirubin, and amylase concentrations. All tetracyclines, except doxycycline, may increase serum BUN
  • Loss of appetite, jaundice, or abdominal pain may indicate possible hepatotoxicity.
  • Minocycline: A change in mental status could indicate possible intracranial hypertension.


Patient Variables To Consider When Prescribing

  • Tetracyclines are well absorbed in the elderly.
  • Doxycycline or minocycline would be a good choice of a tetracycline in the elderly.
  • Tetracyclines should never be given to pregnant patients.
  • Relatively high concentrations of tetracyclines are excreted in breast milk. These drugs are contraindicated during lactation.
  • Except for doxycycline and minocycline, high doses of tetracyclines can cause liver failure
  • Patients should report any signs and symptoms of hepatotoxicity (e.g., persistent nausea, vomiting, anorexia with or without yellow coloring of the skin or eyes, dark urine, pale stools) and should stop taking the medication.
  • Reduction in dosing and/or interval is required in renal impairment, except with doxycycline and minocycline.


Tetracycline Dosages

  • With the exception of doxycycline and minocycline, it is critical that tetracyclines not be taken together with products that contain calcium, magnesium, zinc, or iron (e.g., antacids, milk products, calcium- or iron-containing supplements, iron preparations).
  • Doxycyline is the only drug in this class that must not be taken with food and requires dosing adjustment in renal impairment.
  • Doxycycline (Vibramycin, Doxy Caps) is associated with fewer reports of renal failure than the other tetracyclines. It also offers the advantage of twice-daily dosing.
  • Doxycycline is recommended for the treatment of patients with community-acquired methicillin-resistant Staphylococcus aureus (MRSA).



  • Erythromycin, azithromycin, and clarithromycin are commonly used in primary care. They have primary indications and are used as an alternative to penicillin in sensitive patients.
  • Major limitation to erythromycin use is the occurrence of GI side effects and drug interactions. The newer macrolides (azithromycin and clarithromycin) rarely cause problematic GI side effects.
  • Macrolides affect the cytochrome P450 3A4 system, thereby inhibiting the metabolism of certain drugs.


Macrolide: erythromicin

  • Upper respiratory infection mild to moderate, lower respiratory infection, Adult: 250–500 mg QID × 10 days.
  • Respiratory tract, Adult: 500 mg qid × 5–10 days
  • Skin and skin structure, Adult: 250–500 mg qid × 10 days.
  • Whooping cough, Adult: 500 mg qid × 14 days.
  • Diphtheria; eradicate carriers, Adult: 500 mg q6h × 10 days


Biaxin (clarithromycin)

  • Pharyngitis, tonsillitis, 250 mg q12h × 10 days
  • Acute sinusitis, 500 mg q12h × 14 days
  • Acute exacerbation of COPD, 500 mg q12h × 7–14 days
  • CAP (pneumonia), 250 mg q12h × 7 days
  • Skin, 250 mg q12h × 7–14 days


Zithromax (azithromycin)

  • Acute exacerbation of COPD, CAP, pharyngitis, tonsillitis, skin, Adult: 500 mg × 1 day, then 250 mg × 4 days.
  • Otitis media, Child (>6 mo): 30 mg/kg (maximum, 1500 mg) × one dose, or 10 mg/kg (maximum, 500 mg) once daily × 3 days.
  • CAP, Child: 10 mg/kg × 1 day, then 5 mg/kg × 4 days


Macrolides Key Notes

  • Most practitioners consider the macrolides to be a safe first-line choice for patients with uncomplicated infection
  • When a macrolide is prescribed, caution should be taken with dosing in the presence of severe renal or hepatic impairment.
  • Erythromycin is a first-choice drug for the treatment of children with pneumonia (ages 3 months to 5 years) Erythromycin is an alternative treatment for impetigo, cellulitis, otitis media, pharyngitis, chlamydia, and Lyme disease. Erythromycin also provides alternative treatment for the prevention of bacterial endocarditis in patients allergic to penicillin.
  • Azithromycin is another first-choice drug for the treatment of pneumonia in children (ages 6 months to 5 years and older). Azithromycin also is a first-choice drug for the treatment of chlamydia in adults and is used alternative treatment for patients with impetigo, cellulitis, sinusitis, pharyngitis, acute exacerbations of COPD, and traveler’s diarrhea.
  • Clarithromycin is used in adults for pharyngitis, sinusitis, otitis media, acute exacerbation of COPD, pneumonia, and skin infection.
  • The macrolides are active primarily against gram-positive organisms, including Streptococcus pyogenes and S. pneumoniae.
  • The newer macrolides have added effectiveness against gram-negative bacteria and anaerobes.
  • Macrolides are of value for their unique ability to treat atypical pathogens such as M. pneumonia, which are seen in community-acquired pneumonias.
  • Azithromycin and clarithromycin have significantly increased potency against gram-negative bacteria and anaerobes and generally are reserved for more complicated infections such as community-acquired pneumonia, exacerbation of COPD, and sinusitis.
  • When used long term, monitoring of hepatic function is prudent, especially for erythromycin estolate.
  • Lower doses of macrolides generally are not necessary in the elderly, provided they do not have severe renal or hepatic impairment.
  • Check renal and hepatic function before beginning treatment with the drug.
  • These drugs should not be used in pregnancy except in clinical circumstances when no alternative is available
  • Renal/hepatic function impairment: Erythromycin is excreted by the liver. Exercise caution in administering to patients with impaired hepatic function.
  • Azithromycin is eliminated principally via the liver, exercise caution when administering to patients with impaired hepatic function.
  • Clarithromycin is excreted principally via the liver and kidney and may be administered without dosage adjustment to patients with hepatic impairment and normal renal function. However, in severe renal impairment, the dosage should be halved or dosing intervals doubled.



  • Older Macrolides: ↑ Oral anticoagulants, benzodiazepines, buspirone, carbamazepine, cyclosporine, digoxin, disopyramide, ergot alkaloids,statins, and theophylline.
  • Erythromycin: ↑ bromocriptine, felodipine, grepafloxacin, sparfloxacin, methylprednisolone, ↓ clindamycin.
  • Newer Macrolides: ↑ omeprazole
  • Clarithromycin: Increase digoxin, 3A4 drugs
  • Azithromycin: Increase cisapride, phenothiazine, pimozide(Orap)
  • Pimozide (Orap): ↑ Macrolides
  • Rifampin, theophylline: ↓ Macrolides
  • Fluconazole: ↑ Newer macrolides





Fluoroquinolones = Quinolones

  • Lower respiratory infections
  • Skin and skin structure infections
  • Bone/joint infections
  • Infectious diarrhea
  • Sexually transmitted diseases
  • Complicated urinary tract infections
  • Prostatitis
  • Otitis media, otitis externa
  • Conjunctivitis, corneal ulcers
  • The fluoroquinolones are a group of potent antibiotics with a wide spectrum of action against gram-positive and gram-negative organisms.
  • The primary care provider should be familiar with ciprofloxacin, moxifloxacin, and levofloxacin.
  • Fluoroquinolones have a good safety profile and excellent absorption after oral administration.
  • Headache and dizziness occur in up to 11% of patient.
  • Quinolones are active against aerobic gram-negative bacilli, especially Enterobacter, Haemophilus, and gram-negative cocci such as Neisseria and M.Catarrhalis. They are active against Staphylococcus and Mycoplasma.
  • Ciprofloxacin and levofloxacin are the only quinolones active against Pseudomonas aeruginosa.



  • E. coli, Klebsiella, Proteus, Enterobacter, Uncomplicated UTI, Cystitis (mild/moderate), Cystitis (severe): 250 mg bid × 3 days, 250 mg bid × 7–14 days, 500 mg bid × 7–14 days.
  • M. catarrhalis, H. influenzae, M. pneumoniae, Listeria, Legionella, Staphylococcus , Lower respiratory tract, skin, and skin structure: 500–750 mg bid × 7–14 days.
  • Sinusitis: 500 mg q12h × 10 days
  • Shigella, Serratia, Salmonella , Infectious diarrhea; intraabdominal, 500 mg bid × 5–7 days (Salmonella), 500 mg bid × 3 days (Shigella)



  • Same ciprofloxin plus GABHS(group A β-hemolytic Streptococcus pyogenes)., many gram-negative bacteria.
  • Acute exacerbation of COPD
  • CAP (community-acquired pneumonia)
  • Sinusitis
  • Skin, soft tissue
  • Uncomplicated UTI

500 mg once daily × 7–14 days,500 mg once daily × 10–14 days,

500 mg once daily × 7–10 days, 250 mg once daily × 3 days.



  • Same as ciprofloxacin plus anaerobic activity (Bacteroides spp), Uncomplicated UTI 400 mg once daily × 3 days.
  • Sinusitis, 400 mg once daily × 3 days,400 mg once daily × 10 days.
  • Acute exacerbation of COPD, 400 mg once daily × 5 days.
  • CAP, 400 mg once daily × 7–14 days.
  • Skin and soft tissue (uncomplicated), 400 mg once daily × 7 days



  • Same as ciprofloxin plus GABHS (group A β-hemolytic Streptococcus pyogenes), many gram-negative
  • CAP: 320 mg po once daily × 7 days.
  • Acute exacerbation of COPD: 320 mg po once daily × 5 days.
  • CAP, Community-acquired pneumonia; GABHS, group A β-hemolytic Streptococcus pyogenes.


Fluroquinolone Key Notes

  • Fluoroquinolones should not be considered first-line antibiotics for mild infection; however, they are often the agent of first choice for UTIs and pyelonephritis because of the frequency of resistant bacteria with these conditions.
  • They should be reserved for moderate infections and bacterial infections that are resistant to other antibiotics.
  • Because fluoroquinolones have good tissue penetration, they provide effective treatment for skin, bone, and genital infections.
  • Considered first-choice drugs for empirical treatment of complicated sinusitis, severe diarrhea, UTIs, pyelonephritis, and prostatitis.
  • They are acceptable as an alternative treatment for dog bite, acute sinusitis, severe sinusitis, and chlamydia.
  • Are active against many gram-positive organisms; gram-negative organisms, including M. catarrhalis, H. influenzae, E.coli, chlamydia, and M. pneumoniae; and anaerobes.
  • Monitor renal, hepatic, and hematopoietic function during prolonged therapy.
  • Patients on warfarin anticoagulation should be monitored closely for prothrombin times and INR at baseline daily for the first week of therapy, and weekly thereafter.
  • Patients on any theophylline product should have serum theophylline levels monitored because theophylline clearance may be decreased with concomitant fluoroquinolone use.
  • Evaluate renal and hepatic function at baseline and every 6 weeks if therapy is to be continue
  • Monitor hematology parameters periodically for evidence of leukopenia, hemolytic anemia, and thrombocytopenia.
  • Monitor for CNS side effects such as headache, weakness, shaking, dizziness, drowsiness, and confusion.
  • Elderly patients are more likely than others to have reduced renal function, which increases the half-life of the fluoroquinolone.
  • Dosages should be adjusted in patients with impaired renal function. Also, older adults are more prone to develop tendon rupture and adverse CNS reactions.
  • Use during pregnancy only if the potential benefit justifies the potential risk to the fetus.
  • Fluoroquinolones reach breast milk concentrations equal to serum levels within 2 hours of administration. Because of the association of fluoroquinolones with articular damage, these agents are not recommended for use in nursing mothers.
  • Even though the fluoroquinolones are metabolized in the liver, elimination depends on renal function. Fluoroquinolones are excreted primarily through the renal system; adjustment of the dose is essential in patients with impaired renal function.
  • Warnings have been issued for some fluoroquinolone antibiotics for the increased risk of tendon ruptures of shoulder, hand, Achilles, and other tendons in people older than 65 years, especially those receiving concomitant treatment with corticosteroids.
  • These may occur during therapy or up to several months after discontinuation of drugs. There also may be at risk for serious and potentially fatal adverse events that may occur after repeated doses.
  • Patients should be advised to discontinue therapy if they experience related symptoms and to rest and avoid exercise until tendonitis and tendon rupture have been ruled out.
  • The products identified with increased risk are second-generation quinolones ciprofloxacin (Cipro); and ofloxacin (Floxin) and the third-generation quinolone levofloxacin (Levaquin)





  • Oral: Suppression of oral bacterial flora
  • Topical: Irrigation of infected wounds
  • Parenteral: Complicated UTIs, complicated respiratory infections, skin/bone/soft tissue infections, CNS infection, GI infection (peritonitis)


Aminoglycosides Susceptible Organisms

  • Acinetobacter
  • Enterobacter
  • Escherichia coli
  • Klebsiella
  • Proteus
  • Pseudomonas
  • Serratia
  • Staphylococcus aureus
  • P. aeruginosa
  • Reserved for the treatment of patients with serious gram-negative infections that are resistant to other antibiotics. They normally are not used in primary care, but they are important antibiotics, and all providers should be familiar with their use.
  • Are more potent than other antibiotics and are used systemically for serious infections. Aminoglycosides have a narrow therapeutic window, so careful dosing based on the pharmacokinetics of the drug is required.
  • These agents are associated with significant nephrotoxicity , ototoxicity , and neuromuscular blockade (extremely rare).
  • Aminoglycosides interact with β-lactam antibiotics. destroying the β-lactam ring, an amino group that renders both antibiotics inactive.
  • They are excreted by the kidneys, so patients with impaired renal function is at increased risk for drug toxicity
  • Aminoglycosides are not first-line drugs and are used only in patients with life-threatening infection.
  • Irreversible deafness or renal failure may result from extremely high concentrations of aminoglycosides in the blood.
  • Their use in infections: either IV, IM, or topically.
  • Death may occur as the result of neuromuscular blockade following irrigation of small and large surgical fields with an aminoglycoside preparation.
  • Oral Use:for suppression of GI bacterial flora and in the treatment of patients with hepatic coma.
  • Topical Use: have a wide variety of topical uses.
  • Clinically significant serum levels have occurred following topical use of aminoglycosides for surgical procedures (e.g., gut sterilization)
  • Irreversible deafness or renal failure may result from extremely high concentrations of aminoglycosides in the blood.
  • Consider potential toxicity when ordering aminoglycoside irrigation of a wound.
  • Parenteral Use: are reserved for short-term treatment (<10 to 14 days) of patients with serious infection caused by susceptible strains of gram-negative bacteria, to minimize the risk of toxicity.
  • The decision to continue therapy with a particular drug should be based on the results of susceptibility tests, the severity of infection, the response of the patient, and the important additional considerations of state of hydration, renal status, and other medications that may be taken concomitantly


Patient Variables To Consider When Prescribing Aminoglycosides

  • Serum peak (drawn approximately 30 to 45 minutes after IV dosing; 60 minutes after IM dosing) and trough (drawn immediately before dosing) levels should be monitored after the second or third dose and every 3 to 4 days thereafter for the duration of therapy.
  • During treatment,collect urine specimens for examination during therapy.
  • Monitor serum calcium, magnesium, and sodium.
  • Test eighth cranial nerve function by serial audiometric testing. Hearing loss in the high-frequency range usually occurs.
  • Monitor kidneys through creatinine and BUN values.
  • Geriatrics: Diminished glomerular filtration rate related to aging may prolong the drug’s half-life and increase the risk of toxicity.
  • Pregnancy & lactation: Category C drugs: gentamicin, tobramycin, and amikacin , Category D: neomycin, streptomycin, and kanamycin
  • Aminoglycosides are associated with significant nephrotoxicity and ototoxicity.
  • Carefully monitor BUN, creatinine, and creatinine clearance values. Recovery of renal function occurs if the drug is stopped at the first sign of renal impairment
  • Electrolyte imbalance may be seen as decreased serum levels of sodium, potassium, calcium, and magnesium.
  • It is essential to maintain adequate hydration, especially with the elderly.
  • Neuromuscular blockade can occur and may result in respiratory paralysis.


Neomycin (ingredient in Cortisporin,Neosporin)

  • Oral administration of neomycin decreases intestinal bacterial levels and may be useful in treating patients with bacterial diarrhea or preoperative bowel sterilization.
  • Used topically and ophthalmologically for superficial infection of the skin, ears, and eyes.
  • Irrigation of the urinary bladder with neomycin is effective in preventing bacteriuria in patients with indwelling urinary catheters.
  • An irrigant is intended only for genitourinary use because irrigation of other wounds or sites increases the risk of systemic absorption.




  • UTIs
  • Acute exacerbation of COPD
  • Pneumonia
  • Traveler’s diarrhea
  • Diverticulitis
  • Sinusitis
  • Have a wide antibacterial spectrum that includes both gram-positive and gram-negative organisms; they are most commonly used for UTI’s
  • Continues to have a place in the treatment or prophylaxis of specific clinical conditions such as Pneumocystis pneumonia, toxoplasmosis, typhoid fever, pertussis, and (CA-MRSA).
  • Sulfonamides and tetracycline antibiotics remain valuable low-cost agents for use with most CA-MRSA soft tissue and skin infections.
  • Frequent allergic reactions and drug resistance limit extensive use of sulfonamides.
  • Sulfamethoxazole is combined with trimethoprim (TMP/SMX) for its synergistic effect and is the most commonly used of the sulfonamides.
  • Silver sulfadiazine is frequently used in wound infections and burns.
  • Topicals include sulfonamides that are not absorbed systemically; these are used topically, particularly in the eye and ear.
  • Sulfisoxazole: H. influenza, S. pneumoniae, Pneumocystis pneumonia, toxoplasmosis, typhoid fever, Pertussis, UTI, otitis media, bronchitis, pneumonia, traveler’s diarrhea, diverticulitis, sinusitis, dog bite.
  • Sulfamethoxazole :Same as above. Adult: 2 g initially, maintenance dose 1 g bid.
  • Sulfadiazine: same as above, Adult: Loading dose 2–4 g, then 2–4 g/day in three to six divided doses
  • TMP/SMX: Same as above plus Shigella: dog bite, UTI and otitis media, shigellosis (× 5 days), Adult: 160 TMP/800 SMX q12h × 10–14 days
  • The increasing frequency of resistant organisms has limited the usefulness of the sulfonamides. Resistance develops quickly to sulfonamide alone, and cross-resistance is common.
  • The addition of trimethoprim improves sulfonamide activity somewhat. Sulfonamide allergy is fairly common and can be serious with severe skin reactions. This also limits its usefulness.
  • TMP/SMX is the first-line treatment for acute bacterial exacerbation of COPD and diverticulitis. It is an alternative treatment for dog and human bites, acute sinusitis, diarrhea, UTIs, and pyelonephritis.
  • Sulfonamides are active against some gram-positive and some gram-negative bacteria, but not against anaerobes.


Variables To Consider When Prescribing Sulfonamides

  • Sulfonamide or “sulfa” allergy is fairly common, occurring in about 6% of the general population.
  • Blood levels should be measured in patients receiving sulfonamides for serious infection.
  • TMP/SMX should be used with caution in patients with impaired renal or liver function and in those with chronic folate deficiency, asthma, or severe allergy. Use with caution in (elderly, chronic alcoholics, anticonvulsant therapy, malabsorption de, malnutrition).
  • The use of TMP/SMX in the elderly results in an increased risk of severe reactions, especially when used in conjunction with other drugs or in those with impaired renal or liver function.
  • The most frequently reported severe adverse reactions in the elderly include skin reactions, bone marrow depression, and decreased platelets, with/without purpura. The elderly patient who is also taking certain diuretics, especially thiazides, may have an increased incidence of thrombocytopenia with purpura.
  • Category C/D: Do not use at term (category D). Because TMP/SMX may interfere with folic acid metabolism, use during pregnancy only if the potential benefits outweigh the potential hazards to the fetus.
  • Lactation: Excreted in breast milk
  • Patients should be instructed to drink one 8-ounce glass of water with each dose and several times a day to prevent crystalluria.
  • Patients should avoid prolonged exposure to sunlight because photosensitivity may occur.
  • Patients should notify the provider if hematuria, rash, tinnitus, dyspnea, fever, chills, or sore throat
  • Hypersensitivity: Although rare, fatalities associated with the sulfonamides have occurred as the result of hypersensitivity of the respiratory tract.
  • Stevens-Johnson syndrome, hepatic necrosis may occur.
  • Rash, sore throat, fever, arthralgia, cough, shortness of breath, pallor, purpura, and jaundice may be early signs of serious reactions. The drug should be discontinued at the first sign of any adverse reaction.


Sufonamide D-I

  • ↑ Oral anticoagulants, hydantoins, methotrexate, sulfonylureas, tolbutamide, uricosuric agents.
  • ↓ cyclosporine
  • TMP/SMX: ↑ Diuretics, zidovudine(Retrovir)
  • Thiazide diuretics, indomethacin, probenecid, salicylates ↑ Sulfonamides


Aminoglycoside Key Notes

  • The correct time to draw the peak and trough levels for aminoglycosides: medication is given prior to dosing for the trough and 60 minutes after administration for the peak.
  • Aminoglycosides are associated with ototoxicity and nephrotoxicity.May cause hearing loss
  • Amikacin , gentamicin, and tobramycin are used to tx urosepsis.
  • Geriatric patients are susceptible to the toxic effects of aminoglycoides, monitor kidney function and hydration.
  • May cause hearing loss


Sulfonamide Key Notes

  • The patient must maintain adequate levels of hydration to prevent the development of crystalluria.
  • A sore throat could be indicative of an adverse reaction
  • Sulfonamide or sulfadiazine are considered 1st line choice agents, given in 4 to 6 divided doses is most appropriate for a child who has experienced a dog bite.
  • Silver sulfadiazine is used to tx wound infections and burns.
  • Symptoms that would indicate an elderly pt has a severe adverse rxn to TMP/SMX are skin reactions, bone marrow depression, and decreased platelets.
  • UTIs,acute exacerbation of COPD, pneumonia, sinusitis, traveler’s diarrhea are conditions that can be treated w/ a sulfonamide.


Penicillin Key Notes

  • Unlabeled uses: prophylactic treatment of children with sickle cell anemia.
  • Dexamethasone may be added to therapy in children with bacterial H. influenza meningitis to decrease the risk of hearing loss in children.
  • A pregnant female in her last week of pregnancy with a UTI, should not be treated with Macrodantin (nitrofurantoin).
  • Mild or mod C.difficle –infections can be treated with oral metronidazole.
  • DOC for acute pharyngitis is Penicillin.


Macrolide Key Notes

  • Azithromycin(Zithromax) is the macrolide that requires administration of a loading dose.
  • Hearing loss can occur with the use of erythromycin.
  • Azithromycin should not be used not used w/ a pt who has been given the diagnosis of pneumonia and for whom oral treatment is inappropriate.
  • Erythromycin is the first-choice drug for treatment of pneumonia in children (ages 3 months to 5 years).
  • Azithromycin is used for chlamydia infections.


Fluoroquinolone Key Notes

  • Rashes are the most common reaction to these drugs.
  • Always give the fluoroquinolones orally.
  • Be careful with the elderly patients esp. those with joint and tendon dysfunction.
  • Dose must be adjusted with impaired renal function.


Cephlasporin Key Notes

  • The symptom most commonly associated w/ over dosage of cephalexin (Keflex) is a development of seizures.
  • Cefaclor(Ceclor) may cause serum sickness.
  • Cefixime (Suprax) can cause diarrhea severe enough to discontinue the drug.
  • Only cefuroime Ceftin and ceftriaxone(Rocephin) are administered by the IM or IV route.


Tetracycline Key Points

  • Use of the TCNs is contraindicated in children younger than age 8 because of permanent staining of the teeth.
  • Doxycycline can be administered safely with either milk or an antacid. The other TCNs can not
  • When treating a patient with minocycline, a change in mental status could indicate possible intracranial hypertension
  • Doxycycline can be used to treat Lyme’s de, chlamydia infections, nongonococcal urethritis.
  • If a patient is allergic to PCN than Doxycycline is used 10-14 days.



Edmunds, M. W., & Mayhew, M. S. (2014). Pharmacology for the primary care provider

(4th ed.). St. Louis, MO: Elsevier Mosby

Harvey, R. A., Clark, M. A., Finkel, R., Rey, J. A., & Whalen, K. (2012). Drugs affecting the cardiovascular system. In Pharmacology (pp. 193-218). Baltimore, MD: Wolters Kluwer/Lippincott Williams & Wilkins.