Diuretics, also known in medicine as diuretics, have become a staple in the home medicine cabinets of many Spaniards. They are prescribed for serious conditions such as high blood pressure or heart failure. However, behind their apparent simplicity—the ability to remove excess fluid from the body—lies a complex mechanism that requires strict medical supervision. Improper use of these drugs, especially in the pursuit of rapid weight loss, can lead to serious health consequences. Renowned pharmacist Esther Baste helped shed light on the nuances of using these medications, dispelled popular misconceptions, and explained how to avoid dangerous mistakes.
What underlies the diuretic effect?
Essentially, diuretics make the kidneys work harder to remove excess salt and water through urine. Think of our body as a complex hydraulic system. Sometimes, pressure in this system rises or excess fluid accumulates. Diuretics act like valves that help release the surplus. But not all ‘valves’ are the same. There are different groups of drugs, each working in its own way. Thiazide diuretics, such as hydrochlorothiazide, act gently and gradually and are often prescribed for long-term hypertension control. Loop diuretics, the most well-known being furosemide, work quickly and powerfully, like opening a floodgate all at once. They are used in emergencies when rapid removal of swelling in the legs or lungs is needed. There are also potassium-sparing diuretics, such as spironolactone, which help eliminate water but retain potassium—a mineral vital for heart health. Natural alternatives exist, like pineapple, asparagus, cucumber, or dandelion infusions, but their effect is not comparable to medications and cannot substitute prescribed therapy.
Side Effects and Hidden Risks
Active fluid removal inevitably carries risks. Along with water, the body loses vital electrolytes—potassium, sodium, and magnesium. Their imbalance can seriously disrupt the heart, muscles, and nervous system. The most common side effects of taking diuretics are dehydration, which manifests as fatigue and intense thirst; muscle cramps due to potassium deficiency; and dizziness caused by a sharp drop in blood pressure. With prolonged use without proper monitoring, these conditions can worsen. That is why doctors insist on regular blood tests for patients who take diuretics on a continuous basis. Specialists monitor potassium and sodium levels, as well as creatinine and urea indicators, to evaluate how the kidneys are handling the load. Any alarming symptoms, such as severe dizziness, rapid heartbeat, intense cramps, confusion, or extreme weakness, require immediate medical attention.
Safety guidelines: what the instructions don’t tell you
For treatment to be effective and safe, it is important to follow a few simple rules. Diuretics are recommended to be taken in the morning to avoid frequent nighttime trips to the bathroom. Although the medication removes fluid, it is necessary to maintain proper hydration and drink enough clean water throughout the day. To replenish potassium losses, especially when taking potent diuretics such as furosemide, it’s advisable to enrich your diet with potassium-rich foods, such as bananas and avocados. It’s extremely important to be aware of drug interactions. Combining diuretics with certain anti-inflammatory drugs (ibuprofen, naproxen) can reduce their effectiveness and harm the kidneys. Combining them with other medications to lower blood pressure or treat heart conditions is absolutely normal and often necessary, but only a doctor should select such combinations, as they can properly calculate dosages and monitor the patient’s condition.
The main danger lies in common misconceptions about diuretics. The most widespread myth is that they help with weight loss. It’s important to understand: they remove water, not fat. Any decrease on the scale will be temporary, while the harm from such “weight loss” can be long-term. Using them to “reduce swelling” before an important event means putting your body at unnecessary risk. These medications are a serious tool for doctors to treat specific conditions, not a cosmetic remedy. Stopping treatment as soon as you feel better is also not advisable, as this may lead to the return of symptoms. A responsible approach and strictly following your doctor’s recommendations are key to ensuring the medication provides only benefits.
