Module 9 14 Penicillin Part 2

Question 1

Question

Answer 1

Answer

Question 2

What severe reactions can result from inadvertent injection into an artery?

Answer 2

Inadvertent injection into an artery can lead to severe reactions, including gangrene, tissue necrosis, and sloughing of tissue.

Question 3

Can compounds coadministered with penicillin cause adverse effects?

Answer 3

Yes, compounds coadministered with penicillin can cause adverse effects.

Question 4

What unusual effects can the procaine component of procaine penicillin G cause when given in large doses?

Answer 4

The procaine component can cause bizarre behavioral effects when administered in large doses.

Question 5

What can rapid administration of large intravenous doses of potassium penicillin G lead to?

Answer 5

Rapid administration of large intravenous doses of potassium penicillin G can lead to hyperkalemia.

Question 6

What are the potential consequences of hyperkalemia caused by potassium penicillin G?

Answer 6

Hyperkalemia can potentially result in dysrhythmias and even cardiac arrest.

Question 7

What electrolyte imbalances may arise from the use of intravenous sodium penicillin G?

Answer 7

Intravenous sodium penicillin G use may lead to electrolyte imbalances.

Question 8

In which patient population should caution be exercised when using sodium penicillin G?

Answer 8

Sodium penicillin G should be used with caution in patients on sodium-restricted diets.

Question 9

What is the most common cause of drug allergies?

Answer 9

Penicillins are the most common cause of drug allergies.

Question 10

What percentage of patients who receive penicillins may experience an allergic reaction?

Answer 10

Allergic reactions to penicillins occur in a range of 0.4% to 7% of patients who receive them.

Question 11

What is the range of severity for allergic reactions to penicillins?

Answer 11

The severity of allergic reactions to penicillins can vary from minor rashes to life-threatening anaphylaxis.

Question 12

Is there a direct relationship between the size of the penicillin dose and the intensity of the allergic response?

Answer 12

No, there is no direct relationship between the dose of penicillin and the intensity of the allergic response.

Question 13

Is prior exposure to penicillins necessary for an allergic reaction to occur?

Answer 13

Yes, prior exposure to penicillins is typically required for an allergic reaction.

Question 14

Can allergic responses to penicillins occur in individuals with no prior penicillin use, and why?

Answer 14

Yes, allergic responses can occur in individuals with no prior penicillin use because they may have been exposed to penicillins produced by fungi or penicillins present in foods of animal origin.

Question 15

Should patients allergic to one penicillin be considered allergic to all other penicillins, and why?

Answer 15

Yes, patients allergic to one penicillin should be considered allergic to all other penicillins due to cross-sensitivity.

Question 16

What percentage of patients may also display cross-sensitivity to cephalosporins?

Answer 16

Approximately 1% of patients may display cross-sensitivity to cephalosporins.

Question 17

Is it generally advisable to use any member of the penicillin family in patients with penicillin allergies?

Answer 17

No, it is generally advisable to avoid using any member of the penicillin family in patients with penicillin allergies.

Question 18

What determines the use of cephalosporins in individuals with penicillin allergies?

Answer 18

The use of cephalosporins depends on the intensity of the allergic response. If the penicillin allergy is mild, using cephalosporins is likely safe. If it’s severe, cephalosporins should be avoided.

Question 19

What should individuals allergic to penicillin be encouraged to do?

Answer 19

Individuals allergic to penicillin should be encouraged to wear a medical identification bracelet to alert healthcare providers to their condition.

Question 20

How are penicillin reactions classified, and what are the three categories?

Answer 20

Penicillin reactions are classified as immediate, accelerated, and delayed.

Question 21

When do immediate penicillin reactions typically occur after drug administration?

Answer 21

Immediate penicillin reactions occur within 2 to 30 minutes after the administration of the drug.

Question 22

What is the time frame for accelerated penicillin reactions?

Answer 22

Accelerated penicillin reactions typically occur within 1 to 72 hours after penicillin exposure.

Question 23

When do delayed penicillin reactions manifest?

Answer 23

Delayed penicillin reactions manifest within days to weeks after penicillin use.

Question 24

What type of antibodies mediate both immediate and accelerated penicillin reactions?

Answer 24

Both immediate and accelerated penicillin reactions are mediated by immunoglobulin E (IgE) antibodies.

Question 25

What is anaphylaxis, and what type of reaction is it?

Answer 25

Anaphylaxis is an immediate hypersensitivity reaction, often severe and life-threatening.

Question 26

Which class of drugs is more frequently associated with anaphylactic reactions than any other?

Answer 26

Anaphylactic reactions occur more frequently with penicillins than with any other drugs.

Question 27

What is the estimated incidence of anaphylaxis associated with penicillins, and how does it relate to mortality risk?

Answer 27

The estimated incidence of penicillin-related anaphylaxis is between 0.004% and 0.04%, but the risk of mortality is high, approximately 10%.

Question 28

What is the primary treatment for anaphylaxis, and how can it be administered?

Answer 28

The primary treatment for anaphylaxis is epinephrine, which can be administered subcutaneously (subQ), intramuscularly (IM), or intravenously (IV).

Question 29

Besides epinephrine, what other form of medical support is often required for anaphylactic reactions?

Answer 29

In addition to epinephrine, respiratory support is often necessary for anaphylactic reactions.

Question 30

What is the recommended duration of patient observation after drug injection to monitor for anaphylactic reactions?

Answer 30

Patients should be observed for at least 30 minutes after drug injection to ensure prompt treatment if anaphylaxis should develop.

Question 31

Can small molecules like penicillin induce antibody formation directly?

Answer 31

No, small molecules, including penicillin, are unable to induce antibody formation directly.

Question 32

What must happen for a small molecule like penicillin to promote antibody formation?

Answer 32

To promote antibody formation, the small molecule must first covalently bond to a larger molecule, usually a protein.

Question 33

What is the term used for a small molecule that has covalently bonded to a larger molecule, typically a protein?

Answer 33

When a small molecule is covalently bonded to a larger molecule, it is referred to as a hapten.

Question 34

What constitutes the complete antigen that stimulates antibody formation?

Answer 34

The complete antigen that stimulates antibody formation is the combination of the hapten and the protein to which it has bonded.

Question 35

What are penicillin antibodies primarily directed at?

Answer 35

Penicillin antibodies are not primarily directed at intact penicillin itself.

Question 36

What stimulates the production of penicillin antibodies?

Answer 36

Antibodies to penicillin are typically stimulated by haptens, which are compounds formed as penicillin degrades.

Question 37

What is the main target of most “penicillin antibodies”?

Answer 37

Most “penicillin antibodies” are directed at various degradation products of penicillin, not the intact drug.

Question 38

Can allergic reactions to penicillin decrease over time?

Answer 38

Yes, allergy to penicillin can decrease over time, and a previous intense reaction doesn’t guarantee a severe reaction will recur.

Question 39

How are the current risk of penicillin allergy and the presence of IgE antibodies assessed in patients with a history of penicillin allergy?

Answer 39

Skin tests are used to assess the current risk of penicillin allergy by injecting a small amount of penicillin allergen intradermally and observing for a local allergic response.

Question 40

What does a positive skin test for penicillin allergy indicate?

Answer 40

A positive skin test indicates the presence of IgE antibodies, which can mediate severe penicillin allergy.

Question 41

What does a negative skin test for penicillin allergy suggest?

Answer 41

If the skin test is negative, it suggests that anaphylaxis is unlikely to occur upon penicillin exposure.

Question 42

Why can skin testing for penicillin allergy be dangerous in some patients?

Answer 42

Skin testing can be dangerous in patients with severe penicillin allergy because it may trigger an anaphylactic reaction.

Question 43

What precautions should be taken when performing skin testing for penicillin allergy?

Answer 43

Skin testing for penicillin allergy should only be conducted if epinephrine and facilities for respiratory support are immediately available to manage potential anaphylactic reactions.

Question 44

What does current guidance recommend in terms of skin testing for penicillin allergy?

Answer 44

Current guidelines recommend skin testing with two reagents, which test for the major and minor determinants of penicillin allergy.

Question 45

Which determinant, major or minor, is responsible for most severe penicillin reactions?

Answer 45

The minor determinants, although less common, are responsible for most severe penicillin reactions.

Question 46

What should be done with all patients being considered for penicillin therapy regarding their allergy history?

Answer 46

All patients should be asked if they have a history of penicillin allergy and details about the reaction.

Question 47

What is often considered an appropriate alternative for patients with a mild penicillin allergy?

Answer 47

Cephalosporins are often considered appropriate alternatives for patients with mild penicillin allergies.

Question 48

Why is it prudent to avoid cephalosporins in cases of a history of anaphylaxis or severe allergic reactions to penicillin?

Answer 48

Cephalosporins should be avoided in such cases due to an approximately 1% risk of cross-sensitivity.

Question 49

When cephalosporin therapy is necessary, what route of administration is preferred for patients with a penicillin allergy?

Answer 49

For patients with penicillin allergy, oral cephalosporin administration is preferred as it carries a lower risk of severe reactions compared to parenteral therapy.

Question 50

What are some effective and safe alternatives for patients with penicillin allergy for treating many infections?

Answer 50

Vancomycin, erythromycin, and clindamycin are effective and safe alternatives for patients with penicillin allergy in treating many infections.

Question 51

In what circumstances might a patient with a history of anaphylaxis require penicillin therapy, even though there is a risk of an allergic reaction?

Answer 51

A patient with a history of anaphylaxis may need penicillin therapy for life-threatening infections when alternative treatments are ineffective.

Question 52

What is the approach to minimize the risk of anaphylactic reactions when using penicillin therapy in such cases?

Answer 52

To minimize the risk of anaphylactic reactions, penicillin should be administered according to a desensitization schedule.

Question 53

How does the desensitization procedure for penicillin therapy work?

Answer 53

The desensitization procedure involves starting with a small dose and gradually increasing it at 60-minute intervals until the full therapeutic dose is achieved.

Question 54

What precautions should be taken when implementing the desensitization procedure for penicillin therapy?

Answer 54

The procedure is not without risk, so facilities for immediate administration of epinephrine and respiratory support should be readily available.

Question 55

Are penicillins considered safe for use in infants with bacterial infections?

Answer 55

Yes, penicillins are used safely in infants with bacterial infections, including syphilis, meningitis, and group A streptococcus.

Question 56

Which age group commonly receives penicillins for the treatment of bacterial infections?

Answer 56

Penicillins are commonly used to treat bacterial infections in children and adolescents.

Question 57

Is there evidence of second or third trimester fetal risk associated with penicillin use in pregnant women?

Answer 57

Although there are no well-controlled studies in pregnant women, available evidence suggests there is no second or third trimester fetal risk associated with penicillin use.

Question 58

Is amoxicillin safe for use in breastfeeding mothers?

Answer 58

Amoxicillin is considered safe for use in breastfeeding mothers. However, data regarding the transmission of some other penicillins through breast milk are lacking.

Question 59

What care concern should be addressed when prescribing penicillins to older adults?

Answer 59

Doses of penicillins should be adjusted in older adults with renal dysfunction.

Question 60

How is penicillin V (penicillin VK) similar to penicillin G?

Answer 60

Penicillin V is similar to penicillin G in most respects.

Question 61

What is the principal difference between penicillin V and penicillin G?

Answer 61

The principal difference is their acid stability: Penicillin V is stable in stomach acid, whereas penicillin G is not.

Question 62

Why has penicillin V replaced penicillin G for oral therapy?

Answer 62

Penicillin V has replaced penicillin G for oral therapy due to its acid stability.

Question 63

Can penicillin V be taken with meals?

Answer 63

Yes, penicillin V may be taken with meals.

Question 64

How have pharmaceutical chemists addressed the inactivation of penicillins by β-lactamases?

Answer 64

They have created penicillins with altered side chains that are highly resistant to β-lactamase inactivation.

Question 65

What are the names of the three penicillinase-resistant penicillins available in the United States?

Answer 65

The three penicillinase-resistant penicillins in the United States are nafcillin, oxacillin, and dicloxacillin.

Question 66

Against which strains of staphylococci are penicillinase-resistant penicillins typically used?

Answer 66

Penicillinase-resistant penicillins are used specifically against penicillinase-producing strains of staphylococci, including S. aureus and S. epidermidis.

Question 67

Why are penicillinase-resistant penicillins considered the drugs of choice for most staphylococcal infections?

Answer 67

They are the drugs of choice because they are highly effective against penicillinase-producing staphylococci.

Question 68

Is it appropriate to use penicillinase-resistant penicillins against infections caused by non–penicillinase-producing staphylococci?

Answer 68

No, these agents should not be used against such infections because they are less active against non–penicillinase-producing staphylococci compared to penicillin G.

Question 69

What does the term MRSA stand for in the context of staphylococcal strains?

Answer 69

MRSA stands for Methicillin-Resistant Staphylococcus aureus.

Question 70

What characterizes MRSA strains in terms of antibiotic susceptibility?

Answer 70

MRSA strains lack susceptibility to methicillin and all other penicillinase-resistant penicillins.

Question 71

What is the proposed mechanism of resistance in MRSA?

Answer 71

Resistance in MRSA is believed to result from the production of penicillin-binding proteins (PBPs) that are inaccessible to penicillinase-resistant penicillins.

Question 72

What is considered the treatment of choice for MRSA infections?

Answer 72

Vancomycin is considered the treatment of choice for MRSA infections.

Question 73

What are the two broad-spectrum penicillins available in the medical field?

Answer 73

The two broad-spectrum penicillins are ampicillin and amoxicillin.

Question 74

How does the antimicrobial spectrum of ampicillin and amoxicillin compare to that of penicillin G?

Answer 74

Ampicillin and amoxicillin have the same antimicrobial spectrum as penicillin G.

Question 75

Which gram-negative bacilli are these drugs particularly effective against?

Answer 75

They exhibit increased activity against certain gram-negative bacilli, including Haemophilus influenzae, Escherichia coli, and Salmonella and Shigella species.

Question 76

What contributes to the broadened spectrum of ampicillin and amoxicillin?

Answer 76

The broadened spectrum is primarily due to their enhanced ability to penetrate the gram-negative cell envelope.

Question 77

Are ampicillin and amoxicillin susceptible to inactivation by β-lactamases?

Answer 77

Yes, both drugs are readily inactivated by β-lactamases.

Question 78

What type of infections are ampicillin and amoxicillin ineffective against?

Answer 78

They are ineffective against most infections caused by S. aureus.

Question 79

Which penicillin was the first broad-spectrum penicillin used in clinical practice?

Answer 79

Ampicillin was the first broad-spectrum penicillin in clinical use.

Question 80

Against which pathogens is ampicillin effective in treating infections?

Answer 80

Ampicillin is effective against infections caused by Enterococcus fecalis, Proteus mirabilis, E. coli, Salmonella and Shigella species, and H. influenzae.

Question 81

What are the most common side effects associated with ampicillin, and how do they compare to other penicillins?

Answer 81

The most common side effects of ampicillin are rash and diarrhea, occurring more frequently with ampicillin than with other penicillins.

Question 82

When does rash typically appear in patients receiving ampicillin therapy, and how can providers differentiate between non-allergic and hypersensitivity-related rash?

Answer 82

Rash generally appears 3 to 10 days after initiating ampicillin therapy. Providers should evaluate to differentiate between non-allergic rash and rash related to a hypersensitivity reaction.

Question 83

What are the available routes of administration for ampicillin, and which penicillin is preferred for oral therapy?

Answer 83

Ampicillin can be administered orally or intravenously. For oral therapy, amoxicillin is preferred.

Question 84

In patients with normal kidney function, what dosages are recommended for ampicillin, and what should be considered for patients with renal impairment?

Answer 84

Dosages for patients with normal kidney function are provided in Table 71.2. Dosage adjustments are needed for patients with renal impairment.

Question 85

What is the structural and functional similarity between amoxicillin and ampicillin?

Answer 85

Amoxicillin is structurally and functionally similar to ampicillin.

Question 86

What is the primary difference between amoxicillin and ampicillin in terms of acid stability?

Answer 86

The primary difference is acid stability, with amoxicillin being more acid stable.

Question 87

Why is amoxicillin preferred for oral therapy when administered at equivalent doses alongside ampicillin?

Answer 87

Amoxicillin achieves higher blood levels than ampicillin when administered orally at equivalent doses, making it the preferred choice for oral therapy.

Question 88

How does amoxicillin compare to ampicillin in terms of causing diarrhea, and what may explain this difference?

Answer 88

Amoxicillin is associated with milder diarrhea compared to ampicillin, possibly because less amoxicillin remains unabsorbed in the intestine.

Question 89

In what form is amoxicillin available in a fixed-dose combination, and what is the role of the accompanying component?

Answer 89

Amoxicillin is available in a fixed-dose combination with clavulanic acid, an inhibitor of bacterial β-lactamases, marketed as Augmentin.

Question 90

Is amoxicillin a commonly prescribed antibiotic?

Answer 90

Yes, amoxicillin is one of the most frequently prescribed antibiotics.

Question 91

What is the only available extended-spectrum penicillin?

Answer 91

Piperacillin is the only available extended-spectrum penicillin.

Question 92

What organisms are included in the antimicrobial spectrum of piperacillin?

Answer 92

The antimicrobial spectrum of piperacillin includes organisms susceptible to the aminopenicillins, as well as Pseudomonas aeruginosa, Enterobacter species, Proteus species (indole positive), Bacteroides fragilis, and many Klebsiella species.

Question 93

Is piperacillin susceptible to β-lactamases, and how does this affect its effectiveness against Staphylococcus aureus?

Answer 93

Piperacillin is susceptible to β-lactamases, and as a result, it is ineffective against most strains of Staphylococcus aureus.

Question 94

What is the primary use of piperacillin in the treatment of infections?

Answer 94

Piperacillin is primarily used for infections caused by Pseudomonas aeruginosa.

Question 95

In which patient population do infections with Pseudomonas often occur, and why can they be challenging to treat?

Answer 95

Infections with Pseudomonas often occur in immunocompromised hosts, and they can be challenging to treat.

Question 96

How can the effectiveness of piperacillin against Pseudomonas be enhanced, and what class of drugs is commonly added to the regimen?

Answer 96

To enhance the effectiveness of piperacillin against Pseudomonas, an antipseudomonal aminoglycoside (e.g., gentamicin, tobramycin, amikacin, netilmicin) may be added to the treatment regimen.

Question 97

Why is it important not to mix piperacillin and the aminoglycoside in the same IV solution?

Answer 97

Mixing high concentrations of penicillins with aminoglycosides can lead to the inactivation of aminoglycosides.

Question 98

What is the antimicrobial spectrum of piperacillin?

Answer 98

Piperacillin has a broad antimicrobial spectrum, making it effective against a wide range of bacteria.

Question 99

Against which bacterium is piperacillin highly active?

Answer 99

Piperacillin is highly active against Pseudomonas aeruginosa, which is its primary target.

Question 100

What potential side effect can piperacillin cause due to its impact on platelet function?

Answer 100

Piperacillin can cause bleeding secondary to disrupting platelet function.

Question 101

How is piperacillin affected by penicillinase enzymes?

Answer 101

Piperacillin is sensitive to penicillinase enzymes.

Question 102

What is the preferred route of administration for piperacillin, and why?

Answer 102

Piperacillin is administered parenterally, usually via the IV route, because it is acid-labile.

Question 103

When are dosage adjustments required for piperacillin?

Answer 103

Dosage adjustments are necessary for patients with renal impairment.

Question 104

What is the fixed-dose combination of piperacillin with a β-lactamase inhibitor, and how is it marketed?

Answer 104

Piperacillin is available in a fixed-dose combination with tazobactam, a β-lactamase inhibitor, and is marketed as Zosyn.

Question 105

What do β-lactamase inhibitors do in the context of antibiotic therapy?

Answer 105

β-lactamase inhibitors are drugs that inhibit bacterial β-lactamases, enzymes that can degrade certain antibiotics.

Question 106

Why are β-lactamase inhibitors combined with penicillins?

Answer 106

They are used in combination with penicillinase-sensitive penicillins to extend the antimicrobial spectrum of the penicillin.

Question 107

What are the three β-lactamase inhibitors used in the United States?

Answer 107

The three β-lactamase inhibitors used in the United States are sulbactam, tazobactam, and clavulanic acid (clavulanate).

Question 108

Are β-lactamase inhibitors available as standalone drugs, or are they only found in combination products?

Answer 108

β-lactamase inhibitors are not available as standalone drugs; they are found only in fixed-dose combinations with penicillins.

Question 109

Name some of the fixed-dose combination products that include β-lactamase inhibitors.

Answer 109

Fixed-dose combination products with β-lactamase inhibitors include: Ampicillin/sulbactam (Unasyn)Amoxicillin/clavulanate (Augmentin andClavulin), Piperacillin/tazobactam (Zosyn andTazocin)

Question 110

What is the primary cause of adverse effects associated with these combination products?

Answer 110

Adverse effects are primarily due to the toxicity of the penicillin component in the combination products.

Question 111

What is the primary therapeutic goal when prescribing penicillins?

Answer 111

The primary therapeutic goal is to treat infections caused by sensitive bacteria.

Question 112

Why is it important to collect baseline data when prescribing penicillins?

Answer 112

Baseline data, including samples for microbiologic culture, helps identify the infecting organism, aiding in appropriate treatment selection.

Question 113

What should be monitored in patients receiving penicillins, and why?

Answer 113

Renal function should be monitored because renal impairment can lead to the accumulation of penicillins to toxic levels.

Question 114

In which patient population should penicillins be used with extreme caution, and why?

Answer 114

Penicillins should be used with extreme caution in patients with a history of severe allergic reactions to penicillins, cephalosporins, or carbapenems.

Question 115

What should healthcare providers monitor to assess the therapeutic effects of penicillin therapy?

Answer 115

They should monitor for indications of antimicrobial effects, such as a reduction in fever, edema, pain, and inflammation.

Question 116

In what situation might a skin test be ordered when prescribing penicillins?

Answer 116

A skin test may be ordered for patients with prior allergic responses to assess their current allergy status and minimize adverse effects.