Adverse Effects And Allergic Reactions - NCLEX Pn

1. What is the priority action for the nurse?
   Answer: Review the new medication for potential cross-sensitivity with penicillin. Before administering any antibiotic to a client with a documented penicillin allergy, the nurse must review the prescribed medication for potential cross-sensitivity. Certain antibiotic classes — most notably cephalosporins, and to a lesser extent carbapenems — share structural similarities with penicillins (beta-lactam ring) that can trigger cross-reactive allergic responses in sensitized individuals. If cross-sensitivity exists, the nurse must withhold the medication and notify the PHCP before administration. Administering without checking (A) risks a serious or fatal allergic reaction. Asking the client if they are 'still allergic' (C) is inappropriate — allergies are not self-resolving, and the client cannot be expected to know their cross-reactivity profile. Documenting a new allergy before the medication is even given (D) is premature and clinically inaccurate.
2. At 1000, the nurse enters the room and finds the client difficult to arouse, with a respiratory rate of 8 breaths/min and SpO2 of 88%. Which finding is the most critical indicator of an adverse medication effect?
   Answer: The respiratory rate of 8 breaths/min. A respiratory rate of 8 breaths/min — well below the normal adult range of 12 to 20 — is the primary mechanism-specific indicator of opioid-induced respiratory depression. Opioids act centrally to decrease the drive to breathe; the most sensitive and specific clinical marker of this effect is a reduction in respiratory rate, particularly below 10 to 12 breaths/min. The SpO2 of 88% (D) is also a critical and alarming finding that must be addressed, but it is a downstream consequence of the depressed respiratory rate rather than the primary mechanism indicator. When respiratory rate is very low, oxygen saturation will fall as a result. Both are serious; however, RR 8 is the finding that most directly identifies opioid toxicity as the cause. Age and medical history (A and B) are predisposing risk factors, not current clinical findings that indicate the adverse effect.
3. Which immediate action should the nurse include in the updated plan of care for this client?
   Answer: Prepare to administer a prescribed dose of naloxone. Naloxone (Narcan) is a competitive opioid antagonist — it rapidly reverses opioid-induced CNS and respiratory depression by displacing morphine from opioid receptors. It is the specific, targeted pharmacological solution to opioid toxicity and is the most appropriate immediate solution for this client's life-threatening situation. Increasing oxygen (A) may temporarily support SpO2 but does not reverse the underlying cause — the client will continue to have a depressed drive to breathe without reversal of the opioid effect. Incentive spirometry (C) requires an alert and cooperative client — this client is difficult to arouse and cannot perform the maneuver. Prone positioning (D) is not an appropriate intervention for opioid respiratory depression and could compromise the airway in an obtunded client.
4. The nurse should recognize this as a potential indicator of which adverse effect?
   Answer: The development of a secondary Clostridioides difficile infection. Broad-spectrum antibiotics disrupt the normal protective microbiome of the gastrointestinal tract, eliminating competing bacteria and allowing Clostridioides difficile (C. diff) to proliferate and produce toxins that damage the colonic epithelium. The classic presentation is multiple episodes of watery, foul-smelling diarrhea — often described as having a distinctive unpleasant odor — following antibiotic use. This is a recognized and serious complication of antibiotic therapy requiring Contact Precautions, specific treatment (oral vancomycin or fidaxomicin), and hand hygiene with soap and water. Watery diarrhea is not a symptom of allergic reaction to antibiotics (A), which would more typically present as rash or urticaria. It is not a normal response (C); multiple daily episodes with this character require investigation. A diet-drug interaction (D) would not present with this specific clinical picture.
5. Ten minutes after the intervention, the client is alert, oriented, and has a respiratory rate of 14 breaths/min. The nurse determines the intervention was successful because:
   Answer: The client's vital signs and level of consciousness have stabilized. The success of naloxone in reversing opioid-induced respiratory depression is measured by the return of the two findings that defined the emergency: restoration of an adequate respiratory rate (now 14 breaths/min, within normal range) and return of normal level of consciousness (now alert and oriented). Together, these confirm that the opioid toxicity has been counteracted and vital organ perfusion is being restored. Pain at 3/10 (B) is a relevant clinical concern but does not measure the reversal of the adverse effect — and the opioid reversal may well have unmasked the underlying pain. Range-of-motion ability (C) is not a meaningful outcome measure for this scenario. SpO2 of 92% on room air (D) is a partial improvement but represents a decrease from the client's 0800 baseline of 95% on 2 L/min supplemental oxygen — it does not confirm full recovery, and SpO2 alone does not capture the respiratory rate or consciousness improvements that define successful reversal.
6. The nurse should recognize this as which type of adverse effect?
   Answer: Photosensitivity related to the pharmacological agent. Photosensitivity is a recognized adverse effect of several medication classes, including tetracyclines, sulfonamides, fluoroquinolones, thiazide diuretics, and certain NSAIDs. These agents can absorb UV radiation in the skin and trigger an exaggerated inflammatory response — producing a sunburn-like reaction after even brief, low-level sun exposure. This is not an allergic reaction (B) in the immunological sense — it is a direct pharmacological effect of the drug interacting with UV light. It is not related to absorption rate (C). Critically, it does not resolve on its own while the client continues taking the medication (D) — the nurse must reinforce teaching: wear protective clothing and sunscreen, avoid prolonged sun exposure, and wear a hat outdoors for the duration of the medication course.
7. Which action should the nurse take first?
   Answer: Check the client's most recent serum potassium laboratory result. Loop diuretics (such as furosemide) cause potassium wasting by blocking reabsorption in the loop of Henle. Muscle weakness, leg cramps, and cardiac arrhythmias are the clinical hallmarks of hypokalemia — the nurse must check the current serum potassium level to confirm the suspected adverse effect before taking further action. This focused data collection step takes seconds, provides critical information for the PHCP notification, and guides the urgency of the response. Encouraging ambulation (A) for a client with muscle weakness and arrhythmia could be dangerous. Increasing oral fluids (C) addresses hydration but does not specifically address the suspected electrolyte imbalance. Applying a warm compress (D) treats a symptom while ignoring the potentially life-threatening arrhythmia.
8. Which finding should the nurse identify as a potential allergic reaction rather than a standard adverse effect?
   Answer: The client develops a localized area of hives and intense itching. The critical distinction in pharmacological adverse event reporting is between a predictable dose-dependent pharmacological adverse effect and an immune-mediated allergic (hypersensitivity) reaction. Urticaria (hives) and pruritus (intense itching) are classic IgE-mediated or immune-complex-mediated allergic responses that indicate the immune system is reacting to the medication as a foreign antigen. These findings can herald anaphylaxis and require immediate action. Nausea (A) and dry mouth with metallic taste (D) are standard predictable pharmacological adverse effects related to the drug's mechanisms of action — they are unpleasant but are not immune-mediated hypersensitivity responses. A heart rate decrease from 80 to 72 (C) is an expected pharmacological effect of an antiarrhythmic medication — therapeutic and anticipated, not an adverse event.
9. Which information should the nurse include in the reinforcement?
   Answer: Notify the provider immediately if you experience swelling of your face or tongue. Angioedema — rapid swelling of the face, lips, tongue, or throat — is a rare but potentially life-threatening adverse effect of ACE inhibitors that requires immediate emergency evaluation. It results from ACE inhibitor-induced accumulation of bradykinin, which can cause dangerous airway compromise. This is the most critical safety information to reinforce. Regarding Choice A: a persistent dry cough does affect 10 to 15% of clients on ACE inhibitors (also mediated by bradykinin accumulation) and is a legitimate adverse effect. However, framing it as simply 'normal' is misleading — clients should report it to their provider, as persistent cough may warrant switching to an ARB. A significant increase in heart rate (C) is not an expected effect of ACE inhibitors. Dry, flaky skin (D) is not a recognized ACE inhibitor adverse effect.
10. A 23-year-old female in an urgent care clinic is prescribed amoxicillin by mouth for sinusitis. Her history includes anaphylaxis to penicillin as a child. Which medication order should the nurse QUESTION based on the client's history?
    Answer: Amoxicillin 500 mg by mouth three times daily This question tests recognition of cross-reactivity between penicillin and other beta-lactam antibiotics requiring medication reconciliation. The client has a history of anaphylaxis to penicillin, and amoxicillin is a penicillin-type antibiotic with high cross-reactivity risk. Questioning the amoxicillin order (A) is appropriate because clients with penicillin anaphylaxis should not receive penicillin derivatives. Acetaminophen (B) is safe and has no cross-reactivity with penicillin. Normal saline nasal spray (C) is a safe symptomatic treatment. Increasing oral fluids (D) is a supportive measure with no allergy concerns. The principle of medication safety is that documented severe allergies must be respected, and cross-reactive medications avoided. A transferable strategy is to recognize that penicillin allergy extends to all penicillin derivatives (amoxicillin, ampicillin) and requires careful consideration of alternative antibiotics.
11. Based on the client's respiratory rate and level of consciousness, which nursing hypothesis is the priority?
    Answer: Impaired gas exchange related to medication-induced respiratory depression. Impaired gas exchange related to medication-induced respiratory depression is the priority nursing hypothesis because it represents an immediately life-threatening condition. At a respiratory rate of 8 breaths/min with an SpO2 of 88%, the client is in acute respiratory compromise with insufficient oxygen delivery to vital organs including the brain. Without immediate intervention, this can progress to respiratory arrest and cardiac arrest. All nursing actions must address this hypothesis first. Risk for infection (A) is a valid post-operative concern but is a lower-acuity hypothesis that does not threaten immediate survival. Acute pain (C) is contradicted by the current presentation — a client in respiratory depression from opioid excess is not experiencing inadequate analgesia. Fluid volume deficit (D) may be a concurrent concern but is secondary to the life-threatening respiratory emergency.
12. A 34-year-old female in an emergency department is treated for pneumonia and has a documented allergy to azithromycin (hives). The medication administration record shows an order for azithromycin 500 mg by mouth now. Which action is the PRIORITY for the nurse?
    Answer: Hold the dose and notify the registered nurse of the allergy This question tests recognition of medication allergy documentation and the nurse's responsibility to prevent allergic reactions. The client has a documented allergy to azithromycin with a previous reaction of hives, and the same medication has been ordered. Holding the dose and notifying the registered nurse (B) is the priority to prevent re-exposure to a known allergen that previously caused an allergic reaction. Administering the medication (A) violates the principle of allergy avoidance and could cause a severe reaction. Asking if the client is willing to take it (C) is inappropriate as it puts the client at risk. Giving with food (D) doesn't prevent allergic reactions. The principle of medication safety is that documented allergies must be strictly observed, and the nurse has a duty to advocate for safe medication administration. A transferable strategy is to always verify allergies before administration and recognize that the nurse must refuse to give medications to which the client has documented allergies.
13. The nurse recognizes that the client's current status is most likely a direct result of which medication?
    Answer: The morphine being delivered via the PCA pump. Morphine is an opioid analgesic that acts as a central nervous system depressant. Its most dangerous adverse effect is respiratory depression — it reduces the brain's sensitivity to carbon dioxide and decreases the drive to breathe, causing both decreased rate and depth of respirations. A PCA pump allows client-controlled dosing that can accumulate to toxic levels, particularly in older adults, clients with COPD (who have reduced respiratory reserve), and those who are sleeping or sedated. The combination of difficulty arousing, RR 8, and SpO2 88% in a client receiving continuous opioid access is the classic presentation of opioid-induced respiratory depression. Surgical prophylactic antibiotics (A) do not cause respiratory depression or altered consciousness. COPD medications (C) such as bronchodilators or inhaled corticosteroids do not cause this pattern. A stool softener (B) has no CNS or respiratory effects.
14. A 76-year-old female in a long-term care facility takes digoxin for heart failure. This morning she reports nausea, poor appetite, and seeing "yellow halos" around lights; apical pulse is 52/min, blood pressure 118/64 mm Hg. Laboratory results show digoxin level 2.6 ng/mL and potassium 3.1 mEq/L. The nurse should IMMEDIATELY report which finding to the registered nurse?
    Answer: Digoxin level 2.6 ng/mL with apical pulse 52/min This question tests recognition of digoxin toxicity and the importance of therapeutic drug monitoring. The client is experiencing classic signs of digoxin toxicity including nausea, anorexia, visual disturbances (yellow halos), and bradycardia with a toxic digoxin level and hypokalemia that potentiates toxicity. The digoxin level of 2.6 ng/mL with bradycardia (B) is the most critical finding as it confirms digoxin toxicity (therapeutic range 0.5-2.0 ng/mL) with cardiac effects. Blood pressure (A) is within acceptable limits. Poor appetite (C) alone could have many causes. The client's age and medication regimen (D) are risk factors but not acute findings. The principle of drug toxicity management is that supratherapeutic levels with symptoms require immediate intervention to prevent serious cardiac arrhythmias. A transferable strategy is to recognize that digoxin has a narrow therapeutic index, and toxicity risk increases with hypokalemia, requiring careful monitoring of both drug levels and electrolytes.
15. While waiting for the reversal agent to be delivered, which action should the nurse take first?
    Answer: Stop the PCA pump infusion immediately. While waiting for naloxone to arrive, the nurse must stop the PCA pump immediately to prevent further opioid delivery. Stopping the source of the medication is a critical step that prevents the adverse effect from worsening while the reversal agent is in transit. Even brief continuation of the PCA pump allows additional morphine to be delivered to a client already in respiratory depression. Assessing bowel sounds (B) is not a relevant or urgent priority in an acute respiratory emergency. Notifying the family (C) is appropriate at some point but is not the first action while the client is in active respiratory compromise. Documentation (D) is necessary but follows clinical intervention — documenting while the source of harm continues puts the documentation before the client's safety.
16. Which action should the nurse take next?
    Answer: Withhold the digoxin dose and notify the primary health care provider (PHCP). Nausea and xanthopsia — the perception of a yellow or yellow-green tint to vision — are hallmark early signs of digoxin toxicity. Digoxin has a narrow therapeutic index, meaning the difference between a therapeutic and toxic dose is small. Administering another dose to a client already showing toxicity symptoms could cause serious cardiac arrhythmias. The nurse must withhold the dose, check the most recent digoxin serum level and electrolytes (especially potassium), and notify the PHCP immediately. Administering the digoxin (A) would worsen the toxicity. Offering food before the dose (B) treats the nausea symptom while ignoring the diagnostic significance of the visual disturbance. Documenting refusal (D) misattributes the problem to the client's appetite rather than recognizing it as an adverse effect.
17. An LPN/LVN on a telemetry unit is caring for four clients. Which client should the nurse see FIRST? 1) A 64-year-old male who received intravenous ceftriaxone 10 minutes ago and now has wheezing, facial flushing, and oxygen saturation 89% on room air. 2) A 41-year-old female taking metformin who reports mild nausea after breakfast; blood glucose is 122 mg/dL. 3) A 70-year-old male taking furosemide who reports increased urination; potassium is 3.6 mEq/L. 4) A 58-year-old female taking diphenhydramine who is drowsy but arousable; respiratory rate is 14/min.
    Answer: Client 1 with wheezing and oxygen saturation 89% after ceftriaxone This question tests prioritization of clients experiencing medication-related adverse effects using the ABCs (airway, breathing, circulation) framework. Client 1 is experiencing signs of anaphylaxis (wheezing, facial flushing) with hypoxemia (oxygen saturation 89%) after receiving ceftriaxone, indicating respiratory compromise. Client 1 with wheezing and low oxygen saturation (C) requires immediate intervention due to airway/breathing compromise. Client 2's mild nausea (A) is a common side effect of metformin that doesn't require urgent intervention. Client 4's drowsiness (B) is an expected effect of diphenhydramine with stable respirations. Client 3's increased urination (D) is the expected therapeutic effect of furosemide with acceptable potassium level. The principle of prioritization is that respiratory compromise always takes precedence over expected side effects or therapeutic responses. A transferable strategy is to use ABC prioritization and recognize that beta-lactam antibiotics like ceftriaxone can cause immediate hypersensitivity reactions requiring emergency intervention.
18. Which clinical findings should the nurse monitor for as indicators of NMS?
    Answer: High fever, muscle rigidity, and altered mental status. Neuroleptic Malignant Syndrome (NMS) is a rare but potentially fatal idiosyncratic reaction to antipsychotic medications. The clinical hallmarks are the tetrad of: hyperthermia (high fever, often above 38.5 C), severe muscle rigidity (lead-pipe rigidity), altered mental status (ranging from confusion to coma), and autonomic instability (diaphoresis, tachycardia, blood pressure lability). Any combination of these findings — especially fever with rigidity — in a client receiving an antipsychotic requires immediate discontinuation of the medication and emergency evaluation. Hypotension with bradycardia (A) is not the NMS pattern; NMS typically produces autonomic instability with tachycardia. A widespread itchy rash with hives (C) describes an allergic/hypersensitivity reaction, not NMS. Drowsiness and decreased urination (D) are nonspecific findings that do not constitute the NMS presentation.
19. A 67-year-old female in a long-term care facility started trimethoprim-sulfamethoxazole by mouth yesterday for a urinary tract infection; history includes sulfonamide allergy (hives). Today she reports itching and has raised, red wheals on her chest and arms; vital signs are temperature 98.6°F (37°C), heart rate 96/min, blood pressure 128/76 mm Hg, respiratory rate 18/min, oxygen saturation 97% on room air. Which action is the PRIORITY for the nurse?
    Answer: Hold the medication and notify the registered nurse immediately This question tests recognition of allergic reactions to medications and appropriate nursing response when a contraindicated drug has been administered. The client has a documented sulfonamide allergy and is now experiencing urticaria (hives) after receiving trimethoprim-sulfamethoxazole, which contains a sulfonamide component. Holding the medication and notifying the registered nurse immediately (A) is the priority action to prevent progression to a more severe allergic reaction. Documenting and reassessing in 1 hour (B) delays necessary intervention when an allergic reaction is occurring. Administering the next dose with food (C) is dangerous as it continues exposure to the allergen. Requesting a different antibiotic (D) is appropriate but not the immediate priority when an active allergic reaction is present. The principle of prioritization in adverse reactions is to stop the offending agent immediately and seek appropriate help. A transferable strategy is to always verify allergies before administration and recognize that any new symptoms after starting a medication could indicate an adverse reaction requiring immediate action.
20. A 60-year-old female in a primary care clinic is starting nitrofurantoin by mouth for an uncomplicated urinary tract infection. She has chronic kidney disease; laboratory results show creatinine 2.3 mg/dL. Which symptom should the nurse instruct the client to report IMMEDIATELY as a possible serious adverse effect?
    Answer: New shortness of breath or persistent cough This question tests recognition of pulmonary toxicity as a serious adverse effect of nitrofurantoin, especially in clients with renal impairment. The client's elevated creatinine (2.3 mg/dL) indicates significant kidney disease, which increases the risk of nitrofurantoin accumulation and toxicity. New shortness of breath or persistent cough (A) could indicate pulmonary fibrosis or pneumonitis, serious adverse effects of nitrofurantoin requiring immediate medical attention. Darker yellow urine (B) is an expected harmless effect of nitrofurantoin. Mild loss of appetite (C) is a minor side effect not requiring immediate reporting. Headache relieved by rest (D) is not concerning if self-limiting. The principle of adverse effect monitoring is that respiratory symptoms with nitrofurantoin require immediate evaluation due to potential for irreversible lung damage. A transferable strategy is to recognize that clients with renal impairment are at higher risk for drug toxicity and require closer monitoring for serious adverse effects.

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