Nitrofurantoin is considered a narrow-spectrum drug because it is effective against only a limited range of bacteria, mainly gram-negative bacteria that cause urinary tract infections.

Some additional explanations are:

Choice A is wrong becauseCiprofloxacin is a broad-spectrum drug that can affect a wide range of bacteria, both gram-positive and gram-negative.

Choice C is wrong becauseTrimethoprim-sulfamethoxazole is also a broad-spectrum drug that can inhibit the growth of many types of bacteria, including some gram-positive and gram-negative bacteria.

Choice D is wrong because None of them is incorrect because nitrofurantoin is a narrow-spectrum drug as explained above.

Normal ranges for urinary tract infection microorganisms are:

• Escherichia coli: less than 10^5 CFU/mL

• Other bacteria: less than 10^4 CFU/mL

Empiric therapy with a broad-spectrum antimicrobial agent is indicated for situations when the causative microorganism is unknown, when the infection is severe or life-threatening, and when there is a need to cover multiple pathogens.

Choice D is wrong because empiric therapy with a broad-spectrum antimicrobial agent is not indicated for situations when there is a risk of resistance.On the contrary, this approach can drive antimicrobial overuse and resistance and should be accompanied by a commitment to de-escalation and antimicrobial stewardship.

Choice E is wrong because empiric therapy with a broad-spectrum antimicrobial agent is not indicated for situations when there is a synergistic effect between two or more agents.

Synergistic effect means that the combined effect of two or more agents is greater than the sum of their individual effects.

This may be desirable in some cases, but it is not a reason to use empiric therapy with a broad-spectrum antimicrobial agent.

This drug has a short half-life, so it needs to be taken frequently to maintain effective levels in your body.The half-life of amoxicillin is61.3 minutes, which means that half of the drug is eliminated from the body in about an hour. To keep a constant amount of the drug in the blood and tissues, it needs to be taken every 8 hours or three times a day.

Choice B is wrong because the minimum bactericidal concentration (MBC) is the lowest concentration of an antibiotic that kills 99.9% of bacteria.

Amoxicillin has a low MBC, which means it is effective at killing bacteria at low doses.

Choice C is wrong because the therapeutic index (TI) is the ratio of the toxic dose to the effective dose of a drug.

Amoxicillin has a high TI, which means it has a wide margin of safety and is unlikely to cause toxicity.

Choice D is wrong because the spectrum of activity refers to the range of bacteria that an antibiotic can kill or inhibit.

Amoxicillin has a broad spectrum of activity, which means it can target many types of bacteria, including gram-positive and gram-negative ones.

Normal ranges for amoxicillin are 5 to 25 mcg/mL for peak levels and less than 0.5 mcg/mL for trough levels.

Peak levels are measured 1 to 2 hours after taking the drug, and trough levels are measured just before the next dose.

Slow down the infusion and administer an antihistamine.The client has developedred man syndrome, which is a common adverse reaction to vancomycin that occurs when the drug is infused too rapidly.It is not a serious or life-threatening condition and can be managed by slowing down the infusion rate and giving an antihistamine to relieve the symptoms.

Choice A is wrong because stopping the infusion and notifying the prescriber immediately is indicated for a severe allergic reaction or anaphylaxis, which is characterized by hypotension, bronchospasm, and laryngeal edema.

Red man syndrome does not cause these signs.

Choice C is wrong because continuing the infusion and documenting the findings is not appropriate for red man syndrome, which requires intervention to prevent further discomfort and complications.

Choice D is wrong because increasing the infusion rate and monitoring vital signs would worsen red man syndrome and increase the risk of ototoxicity and nephrotoxicity, which are serious adverse effects of vancomycin.

Gentamicin is an aminoglycoside antibiotic that can causekidney damage, reduced urine output, blood in the urine, andnephrotoxicity.Patients with impaired renal function, advanced age, dehydration, and those who receive high doses or prolonged therapy are at an increased risk of toxicity.Serum concentrations of gentamicin should be monitored when feasible to assure adequate levels and to avoid potentially toxic levels.

Choice B is wrong because Hepatic is wrong because gentamicin does not have a significant adverse effect on the liver.However, some rare cases of transient hepatomegaly and splenomegaly have been reported.

Choice C is wrong because Cardiac is wrong because gentamicin does not directly affect the heart.However, it can cause electrolyte imbalance (low levels of calcium, potassium, or magnesium in the blood) which can affect the cardiac rhythm.It can also cause hypotension or hypertension in some cases.

Choice D is wrong because Hematologic is wrong because gentamicin does not cause blood disorders.However, it can cause anemia, leukopenia, granulocytopenia, and thrombocytopenia in patients with preexisting renal impairment or who receive concomitant therapy with other nephrotoxic or hematotoxic drugs.It can also cause bleeding due to hypoprothrombinemia in patients with renal failure or who are on anticoagulant therapy.