Module 9 14 Penicillin Part 2 Flashcards
Question
Answer
What severe reactions can result from inadvertent injection into an artery?
Inadvertent injection into an artery can lead to severe reactions, including gangrene, tissue necrosis, and sloughing of tissue.
Can compounds coadministered with penicillin cause adverse effects?
Yes, compounds coadministered with penicillin can cause adverse effects.
What unusual effects can the procaine component of procaine penicillin G cause when given in large doses?
The procaine component can cause bizarre behavioral effects when administered in large doses.
What can rapid administration of large intravenous doses of potassium penicillin G lead to?
Rapid administration of large intravenous doses of potassium penicillin G can lead to hyperkalemia.
What are the potential consequences of hyperkalemia caused by potassium penicillin G?
Hyperkalemia can potentially result in dysrhythmias and even cardiac arrest.
What electrolyte imbalances may arise from the use of intravenous sodium penicillin G?
Intravenous sodium penicillin G use may lead to electrolyte imbalances.
In which patient population should caution be exercised when using sodium penicillin G?
Sodium penicillin G should be used with caution in patients on sodium-restricted diets.
What is the most common cause of drug allergies?
Penicillins are the most common cause of drug allergies.
What percentage of patients who receive penicillins may experience an allergic reaction?
Allergic reactions to penicillins occur in a range of 0.4% to 7% of patients who receive them.
What is the range of severity for allergic reactions to penicillins?
The severity of allergic reactions to penicillins can vary from minor rashes to life-threatening anaphylaxis.
Is there a direct relationship between the size of the penicillin dose and the intensity of the allergic response?
No, there is no direct relationship between the dose of penicillin and the intensity of the allergic response.
Is prior exposure to penicillins necessary for an allergic reaction to occur?
Yes, prior exposure to penicillins is typically required for an allergic reaction.
Can allergic responses to penicillins occur in individuals with no prior penicillin use, and why?
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.
Should patients allergic to one penicillin be considered allergic to all other penicillins, and why?
Yes, patients allergic to one penicillin should be considered allergic to all other penicillins due to cross-sensitivity.
What percentage of patients may also display cross-sensitivity to cephalosporins?
Approximately 1% of patients may display cross-sensitivity to cephalosporins.
Is it generally advisable to use any member of the penicillin family in patients with penicillin allergies?
No, it is generally advisable to avoid using any member of the penicillin family in patients with penicillin allergies.
What determines the use of cephalosporins in individuals with penicillin allergies?
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.
What should individuals allergic to penicillin be encouraged to do?
Individuals allergic to penicillin should be encouraged to wear a medical identification bracelet to alert healthcare providers to their condition.
How are penicillin reactions classified, and what are the three categories?
Penicillin reactions are classified as immediate, accelerated, and delayed.
When do immediate penicillin reactions typically occur after drug administration?
Immediate penicillin reactions occur within 2 to 30 minutes after the administration of the drug.
What is the time frame for accelerated penicillin reactions?
Accelerated penicillin reactions typically occur within 1 to 72 hours after penicillin exposure.
When do delayed penicillin reactions manifest?
Delayed penicillin reactions manifest within days to weeks after penicillin use.
What type of antibodies mediate both immediate and accelerated penicillin reactions?
Both immediate and accelerated penicillin reactions are mediated by immunoglobulin E (IgE) antibodies.
What is anaphylaxis, and what type of reaction is it?
Anaphylaxis is an immediate hypersensitivity reaction, often severe and life-threatening.
Which class of drugs is more frequently associated with anaphylactic reactions than any other?
Anaphylactic reactions occur more frequently with penicillins than with any other drugs.
What is the estimated incidence of anaphylaxis associated with penicillins, and how does it relate to mortality risk?
The estimated incidence of penicillin-related anaphylaxis is between 0.004% and 0.04%, but the risk of mortality is high, approximately 10%.
What is the primary treatment for anaphylaxis, and how can it be administered?
The primary treatment for anaphylaxis is epinephrine, which can be administered subcutaneously (subQ), intramuscularly (IM), or intravenously (IV).
Besides epinephrine, what other form of medical support is often required for anaphylactic reactions?
In addition to epinephrine, respiratory support is often necessary for anaphylactic reactions.
What is the recommended duration of patient observation after drug injection to monitor for anaphylactic reactions?
Patients should be observed for at least 30 minutes after drug injection to ensure prompt treatment if anaphylaxis should develop.
Can small molecules like penicillin induce antibody formation directly?
No, small molecules, including penicillin, are unable to induce antibody formation directly.
What must happen for a small molecule like penicillin to promote antibody formation?
To promote antibody formation, the small molecule must first covalently bond to a larger molecule, usually a protein.
What is the term used for a small molecule that has covalently bonded to a larger molecule, typically a protein?
When a small molecule is covalently bonded to a larger molecule, it is referred to as a hapten.
What constitutes the complete antigen that stimulates antibody formation?
The complete antigen that stimulates antibody formation is the combination of the hapten and the protein to which it has bonded.
What are penicillin antibodies primarily directed at?
Penicillin antibodies are not primarily directed at intact penicillin itself.
What stimulates the production of penicillin antibodies?
Antibodies to penicillin are typically stimulated by haptens, which are compounds formed as penicillin degrades.
What is the main target of most “penicillin antibodies”?
Most “penicillin antibodies” are directed at various degradation products of penicillin, not the intact drug.
Can allergic reactions to penicillin decrease over time?
Yes, allergy to penicillin can decrease over time, and a previous intense reaction doesn’t guarantee a severe reaction will recur.
How are the current risk of penicillin allergy and the presence of IgE antibodies assessed in patients with a history of penicillin allergy?
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.
What does a positive skin test for penicillin allergy indicate?
A positive skin test indicates the presence of IgE antibodies, which can mediate severe penicillin allergy.
What does a negative skin test for penicillin allergy suggest?
If the skin test is negative, it suggests that anaphylaxis is unlikely to occur upon penicillin exposure.
Why can skin testing for penicillin allergy be dangerous in some patients?
Skin testing can be dangerous in patients with severe penicillin allergy because it may trigger an anaphylactic reaction.
What precautions should be taken when performing skin testing for penicillin allergy?
Skin testing for penicillin allergy should only be conducted if epinephrine and facilities for respiratory support are immediately available to manage potential anaphylactic reactions.
What does current guidance recommend in terms of skin testing for penicillin allergy?
Current guidelines recommend skin testing with two reagents, which test for the major and minor determinants of penicillin allergy.
Which determinant, major or minor, is responsible for most severe penicillin reactions?
The minor determinants, although less common, are responsible for most severe penicillin reactions.
What should be done with all patients being considered for penicillin therapy regarding their allergy history?
All patients should be asked if they have a history of penicillin allergy and details about the reaction.
What is often considered an appropriate alternative for patients with a mild penicillin allergy?
Cephalosporins are often considered appropriate alternatives for patients with mild penicillin allergies.
Why is it prudent to avoid cephalosporins in cases of a history of anaphylaxis or severe allergic reactions to penicillin?
Cephalosporins should be avoided in such cases due to an approximately 1% risk of cross-sensitivity.
When cephalosporin therapy is necessary, what route of administration is preferred for patients with a penicillin allergy?
For patients with penicillin allergy, oral cephalosporin administration is preferred as it carries a lower risk of severe reactions compared to parenteral therapy.
What are some effective and safe alternatives for patients with penicillin allergy for treating many infections?
Vancomycin, erythromycin, and clindamycin are effective and safe alternatives for patients with penicillin allergy in treating many infections.
In what circumstances might a patient with a history of anaphylaxis require penicillin therapy, even though there is a risk of an allergic reaction?
A patient with a history of anaphylaxis may need penicillin therapy for life-threatening infections when alternative treatments are ineffective.
What is the approach to minimize the risk of anaphylactic reactions when using penicillin therapy in such cases?
To minimize the risk of anaphylactic reactions, penicillin should be administered according to a desensitization schedule.
How does the desensitization procedure for penicillin therapy work?
The desensitization procedure involves starting with a small dose and gradually increasing it at 60-minute intervals until the full therapeutic dose is achieved.
What precautions should be taken when implementing the desensitization procedure for penicillin therapy?
The procedure is not without risk, so facilities for immediate administration of epinephrine and respiratory support should be readily available.
Are penicillins considered safe for use in infants with bacterial infections?
Yes, penicillins are used safely in infants with bacterial infections, including syphilis, meningitis, and group A streptococcus.
Which age group commonly receives penicillins for the treatment of bacterial infections?
Penicillins are commonly used to treat bacterial infections in children and adolescents.
Is there evidence of second or third trimester fetal risk associated with penicillin use in pregnant women?
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.
Is amoxicillin safe for use in breastfeeding mothers?
Amoxicillin is considered safe for use in breastfeeding mothers. However, data regarding the transmission of some other penicillins through breast milk are lacking.
What care concern should be addressed when prescribing penicillins to older adults?
Doses of penicillins should be adjusted in older adults with renal dysfunction.
How is penicillin V (penicillin VK) similar to penicillin G?
Penicillin V is similar to penicillin G in most respects.
What is the principal difference between penicillin V and penicillin G?
The principal difference is their acid stability: Penicillin V is stable in stomach acid, whereas penicillin G is not.
Why has penicillin V replaced penicillin G for oral therapy?
Penicillin V has replaced penicillin G for oral therapy due to its acid stability.
Can penicillin V be taken with meals?
Yes, penicillin V may be taken with meals.
How have pharmaceutical chemists addressed the inactivation of penicillins by β-lactamases?
They have created penicillins with altered side chains that are highly resistant to β-lactamase inactivation.
What are the names of the three penicillinase-resistant penicillins available in the United States?
The three penicillinase-resistant penicillins in the United States are nafcillin, oxacillin, and dicloxacillin.
Against which strains of staphylococci are penicillinase-resistant penicillins typically used?
Penicillinase-resistant penicillins are used specifically against penicillinase-producing strains of staphylococci, including S. aureus and S. epidermidis.
Why are penicillinase-resistant penicillins considered the drugs of choice for most staphylococcal infections?
They are the drugs of choice because they are highly effective against penicillinase-producing staphylococci.
Is it appropriate to use penicillinase-resistant penicillins against infections caused by non–penicillinase-producing staphylococci?
No, these agents should not be used against such infections because they are less active against non–penicillinase-producing staphylococci compared to penicillin G.
What does the term MRSA stand for in the context of staphylococcal strains?
MRSA stands for Methicillin-Resistant Staphylococcus aureus.
What characterizes MRSA strains in terms of antibiotic susceptibility?
MRSA strains lack susceptibility to methicillin and all other penicillinase-resistant penicillins.
What is the proposed mechanism of resistance in MRSA?
Resistance in MRSA is believed to result from the production of penicillin-binding proteins (PBPs) that are inaccessible to penicillinase-resistant penicillins.
What is considered the treatment of choice for MRSA infections?
Vancomycin is considered the treatment of choice for MRSA infections.
What are the two broad-spectrum penicillins available in the medical field?
The two broad-spectrum penicillins are ampicillin and amoxicillin.
How does the antimicrobial spectrum of ampicillin and amoxicillin compare to that of penicillin G?
Ampicillin and amoxicillin have the same antimicrobial spectrum as penicillin G.
Which gram-negative bacilli are these drugs particularly effective against?
They exhibit increased activity against certain gram-negative bacilli, including Haemophilus influenzae, Escherichia coli, and Salmonella and Shigella species.
What contributes to the broadened spectrum of ampicillin and amoxicillin?
The broadened spectrum is primarily due to their enhanced ability to penetrate the gram-negative cell envelope.
Are ampicillin and amoxicillin susceptible to inactivation by β-lactamases?
Yes, both drugs are readily inactivated by β-lactamases.
What type of infections are ampicillin and amoxicillin ineffective against?
They are ineffective against most infections caused by S. aureus.
Which penicillin was the first broad-spectrum penicillin used in clinical practice?
Ampicillin was the first broad-spectrum penicillin in clinical use.
Against which pathogens is ampicillin effective in treating infections?
Ampicillin is effective against infections caused by Enterococcus fecalis, Proteus mirabilis, E. coli, Salmonella and Shigella species, and H. influenzae.
What are the most common side effects associated with ampicillin, and how do they compare to other penicillins?
The most common side effects of ampicillin are rash and diarrhea, occurring more frequently with ampicillin than with other penicillins.
When does rash typically appear in patients receiving ampicillin therapy, and how can providers differentiate between non-allergic and hypersensitivity-related rash?
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.
What are the available routes of administration for ampicillin, and which penicillin is preferred for oral therapy?
Ampicillin can be administered orally or intravenously. For oral therapy, amoxicillin is preferred.
In patients with normal kidney function, what dosages are recommended for ampicillin, and what should be considered for patients with renal impairment?
Dosages for patients with normal kidney function are provided in Table 71.2. Dosage adjustments are needed for patients with renal impairment.
What is the structural and functional similarity between amoxicillin and ampicillin?
Amoxicillin is structurally and functionally similar to ampicillin.
What is the primary difference between amoxicillin and ampicillin in terms of acid stability?
The primary difference is acid stability, with amoxicillin being more acid stable.
Why is amoxicillin preferred for oral therapy when administered at equivalent doses alongside ampicillin?
Amoxicillin achieves higher blood levels than ampicillin when administered orally at equivalent doses, making it the preferred choice for oral therapy.
How does amoxicillin compare to ampicillin in terms of causing diarrhea, and what may explain this difference?
Amoxicillin is associated with milder diarrhea compared to ampicillin, possibly because less amoxicillin remains unabsorbed in the intestine.
In what form is amoxicillin available in a fixed-dose combination, and what is the role of the accompanying component?
Amoxicillin is available in a fixed-dose combination with clavulanic acid, an inhibitor of bacterial β-lactamases, marketed as Augmentin.
Is amoxicillin a commonly prescribed antibiotic?
Yes, amoxicillin is one of the most frequently prescribed antibiotics.
What is the only available extended-spectrum penicillin?
Piperacillin is the only available extended-spectrum penicillin.
What organisms are included in the antimicrobial spectrum of piperacillin?
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.
Is piperacillin susceptible to β-lactamases, and how does this affect its effectiveness against Staphylococcus aureus?
Piperacillin is susceptible to β-lactamases, and as a result, it is ineffective against most strains of Staphylococcus aureus.
What is the primary use of piperacillin in the treatment of infections?
Piperacillin is primarily used for infections caused by Pseudomonas aeruginosa.
In which patient population do infections with Pseudomonas often occur, and why can they be challenging to treat?
Infections with Pseudomonas often occur in immunocompromised hosts, and they can be challenging to treat.
How can the effectiveness of piperacillin against Pseudomonas be enhanced, and what class of drugs is commonly added to the regimen?
To enhance the effectiveness of piperacillin against Pseudomonas, an antipseudomonal aminoglycoside (e.g., gentamicin, tobramycin, amikacin, netilmicin) may be added to the treatment regimen.
Why is it important not to mix piperacillin and the aminoglycoside in the same IV solution?
Mixing high concentrations of penicillins with aminoglycosides can lead to the inactivation of aminoglycosides.
What is the antimicrobial spectrum of piperacillin?
Piperacillin has a broad antimicrobial spectrum, making it effective against a wide range of bacteria.
Against which bacterium is piperacillin highly active?
Piperacillin is highly active against Pseudomonas aeruginosa, which is its primary target.
What potential side effect can piperacillin cause due to its impact on platelet function?
Piperacillin can cause bleeding secondary to disrupting platelet function.
How is piperacillin affected by penicillinase enzymes?
Piperacillin is sensitive to penicillinase enzymes.
What is the preferred route of administration for piperacillin, and why?
Piperacillin is administered parenterally, usually via the IV route, because it is acid-labile.
When are dosage adjustments required for piperacillin?
Dosage adjustments are necessary for patients with renal impairment.
What is the fixed-dose combination of piperacillin with a β-lactamase inhibitor, and how is it marketed?
Piperacillin is available in a fixed-dose combination with tazobactam, a β-lactamase inhibitor, and is marketed as Zosyn.
What do β-lactamase inhibitors do in the context of antibiotic therapy?
β-lactamase inhibitors are drugs that inhibit bacterial β-lactamases, enzymes that can degrade certain antibiotics.
Why are β-lactamase inhibitors combined with penicillins?
They are used in combination with penicillinase-sensitive penicillins to extend the antimicrobial spectrum of the penicillin.
What are the three β-lactamase inhibitors used in the United States?
The three β-lactamase inhibitors used in the United States are sulbactam, tazobactam, and clavulanic acid (clavulanate).
Are β-lactamase inhibitors available as standalone drugs, or are they only found in combination products?
β-lactamase inhibitors are not available as standalone drugs; they are found only in fixed-dose combinations with penicillins.
Name some of the fixed-dose combination products that include β-lactamase inhibitors.
Fixed-dose combination products with β-lactamase inhibitors include: Ampicillin/sulbactam (Unasyn)Amoxicillin/clavulanate (Augmentin andClavulin), Piperacillin/tazobactam (Zosyn andTazocin)
What is the primary cause of adverse effects associated with these combination products?
Adverse effects are primarily due to the toxicity of the penicillin component in the combination products.
What is the primary therapeutic goal when prescribing penicillins?
The primary therapeutic goal is to treat infections caused by sensitive bacteria.
Why is it important to collect baseline data when prescribing penicillins?
Baseline data, including samples for microbiologic culture, helps identify the infecting organism, aiding in appropriate treatment selection.
What should be monitored in patients receiving penicillins, and why?
Renal function should be monitored because renal impairment can lead to the accumulation of penicillins to toxic levels.
In which patient population should penicillins be used with extreme caution, and why?
Penicillins should be used with extreme caution in patients with a history of severe allergic reactions to penicillins, cephalosporins, or carbapenems.
What should healthcare providers monitor to assess the therapeutic effects of penicillin therapy?
They should monitor for indications of antimicrobial effects, such as a reduction in fever, edema, pain, and inflammation.
In what situation might a skin test be ordered when prescribing penicillins?
A skin test may be ordered for patients with prior allergic responses to assess their current allergy status and minimize adverse effects.
