10 drugs every physician should know

Although it’s highly unlikely that any physician is familiar with all of the over 19,000 prescription drug products currently approved by the FDA, it’s important for all doctors to know about the most important drugs, ones which have either multiple uses, dangerous side effects, or, in some cases, are highly addictive and should not be prescribed. Many of them are “wonder drugs” and others are on the list of “drugs to avoid.”

As such, we’ve compiled a list of 11 drugs that every physician should be familiar with. For optimal patient management, physicians should know the benefits and risks of all these drugs, as well as their indications, contraindications, and possible side effects. 

Gabapentin

The anticonvulsant gabapentin is one of the most commonly prescribed medications, and has broad uses. Although still unclear, gabapentin’s mechanism of action involves neuron excitability. It increases gamma aminobutyric acid (GABA) levels to help with pain reduction. It also suppresses the release of norepinephrine, glutamate, and substance P. Gabapentin can help with neuropathic pain, and may be beneficial in treating some sleep disturbances (eg, insomnia) and anxiety. However, it may cause adverse drug-drug interactions with pain medications, naproxen, and some heartburn medications.

Amoxicillin

Like gabapentin, amoxicillin is another commonly prescribed drug. It’s used to treat a gamut of infections, including bronchitis and pneumonia, as well as ear, nose, throat, skin and urinary tract infections. As such, physicians across specialties are comfortable prescribing it. Amoxicillin is usually well-tolerated, but can cause nausea, vomiting, headache, changes in taste, and other unharmful symptoms. More serious adverse effects include hypersensitivity, which occurs only in 0.1% of patients. The elderly, children, and patients with liver disease, diabetes, kidney disease, and other chronic medical conditions are more likely to experience negative side effects.

Amphotericin B

Amphotericin is a heavy hitter—a drug that is both feared and respected. It is used to treat very severe fungal infections such as fungal meningitis. Its adverse effects are common, quick onset, and lethal; they include fever, hypotension, nausea, vomiting, headache, dyspnea, chills, weakness, and tachypnea. Sometimes these adverse effects occur with subsequent doses. These negative side effects may be due to histamine release and prostaglandin production. Potentially lethal febrile responses need to be managed ASAP.

Cephalexin

This orally administered first-generation cephalosporin is a useful tool to treat a broad range of infections, including respiratory, genitourinary, ear, and skin and soft tissue, as well as strep throat. Like amoxicillin, it represents another drug that could be an easy fix for physicians of any stripe. Got a minor skin infection that doesn’t require the attention of a dermatologist? Bam! Unfortunately, cephalexin can have adverse interactions with multivitamins, minerals, several vaccines, warfarin, and metformin, just to name a few.

Amitriptyline

Chances are that, whatever your specialty, you have encountered patients with depression. If you decide to treat the depression in-house, monotherapy with the tricyclic antidepressant amitriptyline is remarkably effective. Remember to caution your patients that this drug shouldn’t be mixed with alcohol, monoamine oxidase inhibitors (MAOIs), or selective serotonin reuptake inhibitors (SSRIs; ie, serotonin syndrome). This drug can also boost the risk of sunburn, so it’s a good idea to warn your patients to wear protective clothing and sunscreen (SPF 30) while taking it. Common adverse effects include nausea, vomiting, constipation, decreased sex drive, and rash. Hypersensitivity reactions are serious and require immediate medical attention.

Statins

Statins like atorvastatin and simvastatin help prevent heart attack and stroke. But how do they work? Plaques are stabilized or even regressed with statin therapy. Statins’ various mechanisms of action likely include decreased inflammation, enhanced endothelial function, and decreased lipid accumulation around a necrotic lipid core. Since grapefruit juice can decrease the ability of the liver to metabolize some statins, including atorvastatin, simvastatin, and lovastatin, it shouldn’t be consumed while taking a statin medication. Statins have also been associated with increased fasting blood glucose levels, HbA1C, and diabetes, as well as memory loss, forgetfulness, and confusion.

Fentanyl

The opioid crisis has changed the fabric of American society. It’s swallowed whole communities, and disproportionately impacted the disenfranchised. Here’s one to beware of and avoid at all costs: Fentanyl is 50 to 100 times stronger than morphine, and contributes to more than half of American drug overdose deaths in some states. In addition to prescription, this synthetic opioid is also manufactured illegally, and used as a cutting agent to increase heroin potency. Because they are so strong, synthetic opioids need escalating doses of naloxone to treat respiratory depression.

Tetracycline

Inflammatory acne is commonly treated with tetracycline. But, this potent antibiotic has a slew of nasty side effects frequent among users, including gastrointestinal upset, skin rashes, fever, photosensitivity (ie, sunburn), as well as overgrowth of yeasts on the vagina and anus. It also shouldn’t be taken by pregnant women because exposure to the fetus can result in permanent yellow-gray tooth discoloration.

Warfarin

Did you know that some rat poisons contain the blood-thinner warfarin (Coumadin)? When rats squeeze through little holes and crevices they break blood vessels and bleed to death. Which brings to mind how warfarin was discovered in the first place. In the prairies of Depression-era America, cattle began to die from internal bleeding with no overt cause. It turned out that they were eating moldy—not fresh—sweet clover hay because of financial hardship. This moldy hay was later found to contain coumarin.

Physicians should pay close attention to whether their patients are on warfarin. Not only does it increase bleeding risk and require routine INR monitoring but changes in diet can increase vitamin K levels, a clotting agent. Foods that can increase vitamin K levels include beef liver, tofu, broccoli, Brussels sprouts, cabbage, green tea, soy oil, kale, chickpeas, lettuce, seaweed, turnip greens, and spinach.

Metformin

This drug is the most commonly prescribed drug for type 2 diabetes, which makes sense because it is cheap and generic. You may think that metformin is a no-brainer as a first-line therapy, but lots of people can’t stomach it because of gastrointestinal disturbance, including diarrhea, flatulence, stomach pain, nausea, and vomiting. Why people experience these adverse effects is unknown and could be due to genotype, comorbidities, and other medications. Possible means of overcoming metformin tolerance include titration and extended-release formulations. Or, patients can be switched to a much more expensive medication such as sitagliptin.