This summer, I went surfing and developed an ear infection. I was living in Ecuador, where chickens wandered around the open-roof, dirt-floor health clinic. Despite the questionable hygiene, I was prescribed a three-day regimen of the antibiotic Gentamicina. Gentamicina is administered intramuscularly, so the doctor sent me on my way with a 3-inch needle.

Although the first dose was nerve-wracking, I dutifully self-injected the medication each day. Luckily, the ear infection quickly left. It wasn’t until I started losing hearing in my ear that I began to question the efficacy of my medication. A two-hour bus ride to a more urban part of Ecuador revealed that Gentamicina is in fact harmful to one’s kidneys and ears. Wikipedia writes of Gentamicina’s “multiple side effects and high toxicity.” Its use is highly inadvisable and almost outlawed here in the United States.

I was not the only person in Ecuador taking Gentamicina. The general practitioner at the health clinic prescribed it to coughing children, sick mothers and aging grandmothers, because the health clinic lacked updated information on their drug stockpiles. When my friend asked the hospital director about its use, he seemed unconcerned, citing the medication’s availability and low cost. While I was able to return to the United States and check the function of my kidneys, those patients could not.

Misprescribing antibiotics is not just a problem in Ecuador. While the Food & Drug Administration prevents distribution of drugs like Gentamicina, American doctors commonly prescribe antibiotics improperly. It is estimated that 190 million doses of antibiotics are administered each day. Some reports suggest that over 50 percent of those prescriptions are unnecessary.

Part of this is the patient’s fault. We ask for drugs when we feel sick or have the common cold. When NyQuil doesn’t do the trick after the first day, we want something stronger, something official. The quick fix is alluring — after all, penicillin was labeled the “magic bullet” when discovered in the 1940s. But in these circumstances, the bullet misses its target: Since common colds generally arise from viruses, antibiotics are totally ineffective.

Patient compliance is also a significant problem. A recent study found that 19.5 percent of American patients fail to follow their prescriptions. When patients don’t dutifully complete their entire regimen, they expose the bacteria to suboptimal conditions and select for bacteria that are strong enough to overcome the medication. This enables the bacteria to develop resistance, making the drug less effective in its next round of use. The rapid cell cycle of bacteria — some replicate every 40 minutes — only makes this evolution more powerful.

Part of this is also the fault of the doctor. Some physicians will prescribe antibiotics to appease patients. Strapped for time, they don’t have the energy to explain the difference between bacteria and viruses. Or they will prescribe antibiotics to address potential liability. As the number of malpractice lawsuits increases, doctors are looking for ways to cover their bases. Practicing such “defensive medicine” may seem proactive, but it only contributes to cases of antibiotic resistance.

Regardless of its cause, antibiotic resistance is an emerging problem. Last week, the Centers for Disease Control and Prevention reported that at least 2 million Americans fall ill from antibiotic-resistant bacteria every year. This can result in over 23,000 deaths annually. And antibiotic resistance can be significantly more serious than that from a common cold. Tuberculosis strains resistant to routine drugs require longer, more expensive and often less effective treatment courses. MRSA can spread like wildfire in a hospital setting, endangering the lives of many patients and forcing pricey, quarantine-like conditions. CRE, a family of gram-negative bacteria, is now resistant to every class of antibiotics, making it a deadly “superbug.” While it currently only causes 600 deaths a year, it has been identified at health care facilities in over 44 American states.

In her book “The Coming Plague,” Laurie Garrett describes how improper use of antibiotics has contributed to mutations in old diseases. She describes a world weakened by the outbreak of devastating, incurable illnesses. Her forecast is depressing and perhaps exaggerated, but it projects an eerie future. The next time you call Yale Health, think twice before requesting that Z-Pak.

Isabel Beshar is a senior in Saybrook College. Contact her at isabel.beshar@yale.edu.