As a nursing student or nurse, you’ll learn about hundreds of drugs over the span of your career but the ones you’ll know really well are the ones you use on a consistent basis. If you’re just starting out and aren’t sure which drugs to focus on, this list of one dozen common drugs will come in handy in a wide variety of acute care settings. While this article certainly does not convey everything there is to know about each of these medications, it does include the key things to know – what the medication is used for, some specific administration details, and key side effects and assessments.


Why it’s used: You will often see diphenhydramine used to treat pruritus associated with opioid medications and allergic reactions ranging from mild to anaphylaxis. Many times diphenhydramine is administered prior to the patient receiving blood products or medications such as chemotherapy to prevent mild allergic reactions. Though not as common, you may also see it utilized to treat dystonic reactions to medications. Because it causes drowsiness, some patients will take diphenhydramine to help them sleep, but be aware it can cause a paradoxical excitation in children and acute confusion in the elderly. 

Administration details: Diphenhydramine can be administered PO or IV. When diphenhydramine is used to prevent mild allergic reactions, it is given 30 minutes to 1 hour prior to the blood products or chemotherapy treatment.

Side effects and assessment: Drowsiness and dry mouth are two common side effects of diphenhydramine. Monitor elderly patients for acute confusion, which can be quite pronounced.


Why it’s used: Furosemide is a diuretic used to prevent and treat fluid volume overload and hypertension. Typically those who receive furosemide have heart failure, but it may also be utilized in individuals with edema secondary to liver disease or renal impairment.

Administration details: Furosemide can be administered PO or IV. Note that if the medication is given twice per day, the second dose is typically not administered later than 1700 so as to minimize sleep disruption and trips to the bathroom. IV furosemide is usually given as an IV push, but it may be administered as a continuous infusion in critically ill individuals.

Side effects and assessment: Because furosemide exerts its effects on the Loop of Henle, significant potassium losses can occur, so you’ll need to watch your patient for hypokalemia (and possibly replace potassium as well). Additionally, furosemide causes volume losses which can cause hypotension, including orthostatic hypotension. This puts your patient at risk for falls, so teach them to change positions slowly. Key assessments include monitoring your patient’s fluid volume status, potassium level, creatinine level, and blood pressure. If furosemide is being given to treat or prevent pulmonary edema, you’ll also want to auscultate lung sounds, measure SpO2 and observe WOB to ensure the medication is working as intended. 

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Why it’s used: Hydralazine is used to treat hypertension, and it works by causing arterial vasodilation.

Administration details: Hydralazine comes in PO and IV formulations. When giving PO, administer with meals to ensure consistent absorption.

Side effects and assessment: A common side effect of hydralazine is tachycardia, which often prevents it from being used as a first-line agent for hypertension. Other adverse effects include headache, flushing, and dizziness. Your key assessments for a patient taking hydralazine are blood pressure and heart rate.


Why it’s used: Gabapentin is a CNS depressant that is classified in several different ways, making it a diverse and widely used medication. It is in the therapeutic class of anticonvulsants, analgesics and mood stabilizers. Its official indications are to treat seizure, postherpetic neuralgia and restless leg syndrome, but one of the most common uses you’ll see is actually an off-label use and that is for the treatment of neuropathic pain.

Administration details: Gabapentin comes in immediate-release and extended-release PO formulations. Note that some patients will be on significantly high doses and take multiple capsules. However, any time you are opening multiple blister packs, always double check the dose just to be sure.

Side effects and assessment: The key side effect with gabapentin is drowsiness, and it can also cause confusion, dizziness, and ataxia. Note that if your patient is taking other medications that depress the CNS (such as antihistamines or opioids), they are at heightened risk for CNS depression.

Review gabapentin further with the Straight A Nursing DRRUGS framework in the article Focus on Pharm: Gabapentin or listen to Straight A Nursing podcast episode #186: Your Guide to Gabapentin.


Why it’s used: Levothyroxine is used to replace thyroid hormone in individuals with hypothyroidism.

Administration details: Levothyroxine is administered in IV or PO form and typically around 0600 before the first meal of the day. If taken PO, the individual should wait 30 to 60 minutes prior to eating breakfast. Note that foods and medications containing iron, calcium, magnesium or zinc can bind levothyroxine and prevent its full absorption, so supplements and even dairy products should be avoided for about four hours before or after levothyroxine administration.

Side effects and assessment: Side effects from levothyroxine are typically only noted if doses are excessive and resemble hyperthyroidism – tachycardia, sweating, diarrhea, and heat intolerance.

Review levothyroxine further with the Straight A Nursing DRRUGS framework in the article Focus on Pharm: Levothyroxine or tune in to the Straight A Nursing podcast, episode 219.


Why it’s used: Lisinopril is an ACE inhibitor used to treat hypertension and heart failure. It works by disrupting the RAAS pathway – it inhibits angiotensin converting enzyme, which blocks the conversion of angiotensin I to angiotensin II. The overall effect is vasodilation and lower blood pressure.

Administration details: Lisinopril comes in PO form as tablets or an oral solution.

Side effects and assessment: One of the most common side effects of ACE inhibitors is a dry cough that, for many people, is troublesome enough for them to seek alternative therapies. And, of course, as an antihypertensive agent, it can also cause hypotension and dizziness. Lisinopril and other ACE inhibitors can also cause renal impairment and hyperkalemia, so if your patient is also taking potassium supplements or a potassium-sparing diuretic, they will be at especially high risk. Key assessments include potassium levels and blood pressure. 


Why it’s used: Metformin is used to maintain optimal blood glucose levels in individuals with Type 2 diabetes. It works by decreasing hepatic glucose production, decreasing intestinal glucose absorption, and increasing insulin sensitivity.

Administration details: Metformin is administered in PO form and is held if the patient receives IV contrast due to the heightened risk for acute kidney injury.

Side effects and assessment: The most common complaints related to metformin are GI related – abdominal bloating, diarrhea, and nausea/vomiting. It may also cause a metallic taste in the mouth. Monitor your patient’s bowel habits and fluid volume status if diarrhea and vomiting are present. You will also, of course, monitor your patient’s blood glucose levels, especially if they are taking other glucose-lowering medications.


Why it’s used: Metoprolol is a beta blocker that lowers heart rate and blood pressure. It is primarily used to treat hypertension, angina pectoris and heart failure. Some off-label uses include tachycardia, tremors and anxiety due to its effects on the sympathetic nervous system.

Administration details: Metoprolol may be administered PO or IV. Because this medication causes a slowing of the heart rate, assess pulse prior to administration as the order should have a hold parameter if the heart rate is below 50 or 60 bpm.

Side effects and assessment: Common side effects of metoprolol include bradycardia, fatigue, and weakness. Because of metoprolol’s mechanism of action, monitor your patient’s heart rate and blood pressure while taking this medication. 


Why it’s used: Morphine is an opioid analgesic used to treat pain.

Administration details: Morphine comes in IV, epidural, intrathecal, rectal, and PO formulations, with extended release tablets available. PO morphine may be administered with food or milk to minimize GI upset.

Side effects and assessment: The key side effects you’re watching for with morphine (or any opioid) are respiratory depression and sedation. Note that these effects are increased when morphine is taken along with other opioids or other medications that cause CNS depression such as benzodiazepines. Other common side effects include hypotension, nausea, and pruritus. In addition to monitoring respiratory status and blood pressure, you’ll also need to assess your patient’s pain to determine if the medication is effective.


Why it’s used: Prednisone is used in a wide variety of conditions such as autoimmune disease, asthma, allergies, and inflammatory conditions.

Administration details: Prednisone comes in tablet and oral solution formulations. If the dose is ordered daily (or less frequently) the dose is administered in the morning to coincide with the body’s normal cortisol release. Prednisone is administered with meals to minimize potential GI upset.

Side effects and assessment: Some common side effects to watch for with your patient include mood swings, hypertension, hyperglycemia, and nausea. Patients taking prednisone long term can develop osteoporosis, poor wound healing, muscle wasting, and cushingoid appearance (buffalo hump and moon face). Keep a close eye on blood glucose levels, blood pressure, and skin integrity while caring for a patient taking prednisone.


Why it’s used: Simvastatin is used to treat hyperlipidemia and ultimately prevent complications such as myocardial infarction and stroke.

Administration details: Simvastatin comes in tablet form and as an oral suspension. It is generally administered once daily in the evening and patients should avoid grapefruit juice as this can lead to toxicity. 

Side effects and assessment: Common side effects include rash, abdominal cramps, diarrhea, and constipation. Monitor your patient’s lipid levels, bowel habits, and for any signs of muscle weakness. If your patient develops muscle weakness this could be a sign of a serious reaction including rhabdomyolysis. 


Why it’s used: Warfarin is an anticoagulant used to prevent blood clots and pulmonary embolism as well as thrombotic stroke in patients with atrial fibrillation. It is also used to prevent thrombus formation after prosthetic valve placement.

Administration details: Warfarin comes in PO form and the dose is variable depending on the patient’s INR. This means the dose could change as frequently as daily, so careful attention must be given to lab results and administration instructions.

Side effects and assessment: The key thing to watch for in your patient taking warfarin is bleeding. You’ll also be checking the INR daily in the clinical setting to ensure the medication is at therapeutic levels and to assess bleeding risk (higher INR means higher risk for bleeding). In general, a therapeutic INR for most patients will be between 2 and 3, but this can vary depending on why the medication is being utilized.

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Review the key things to know about these drugs on the go by tuning in to episode 331 of the Straight A Nursing podcast. Listen from any podcast platform, or straight from the website here.


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Vallerand, A. H., Sanoski, C. A., & Quiring, C. (2023a). Diphenhydramine. In Davis’s Drug Guide (18th ed.). F.A. Davis Company.

Vallerand, A. H., Sanoski, C. A., & Quiring, C. (2023b). Furosemide. In Davis’s Drug Guide (18th ed.). F. A. Davis Company.

Vallerand, A. H., Sanoski, C. A., & Quiring, C. (2023c). Gabapentin. In Davis’s Drug Guide (18th ed.). F. A. Davis Company.

Vallerand, A. H., Sanoski, C. A., & Quiring, C. (2023d). Hydralazine. In Davis’s Drug Guide (18th ed.). F. A. Davis Company.

Vallerand, A. H., Sanoski, C. A., & Quiring, C. (2023e). Lisinopril. In Davis’s Drug Guide (18th ed.). F. A. Davis Company.

Vallerand, A. H., Sanoski, C. A., & Quiring, C. (2023f). Metformin. In Davis’s Drug Guide (18th ed.). F. A. Davis Company.

Vallerand, A. H., Sanoski, C. A., & Quiring, C. (2023g). Morphine. In Davis’s Drug Guide (18th ed.). F. A. Davis Company.

Vallerand, A. H., Sanoski, C. A., & Quiring, C. (2023h). Prednisone (Rayos). In Davis’s Drug Guide (18th ed.). F.A. Davis Company.

Vallerand, A. H., Sanoski, C. A., & Quiring, C. (2023i). Simvastatin. In Davis’s Drug Guide (18th ed.). F. A. Davis Company.

Vallerand, A. H., Sanoski, C. A., & Quiring, C. (2023j). Warfarin (Coumadin, Jantoven). In Davis’s Drug Guide (18th ed.). F. A. Davis Company.

Vallerand, A. H., Sanoski, C., & Quiring, C. (2023k). Levothyroxine. In Davis’s Drug Guide (18th ed.). F. A. Davis Company.

Vallerand, A. H., Sonaski, C. A., & Quiring, C. (2023). Metoprolol. In Davis’s Drug Guide (18th ed.). F. A. Davis Company.