Hydrochlorothiazide (HCTZ) is a thiazide diuretic used to treat hypertension (high blood pressure) and manage edema (fluid buildup). HCTZ works by helping the kidneys remove excess salt and water, which lowers blood pressure. Since panic attacks involve intense physical symptoms, it is important to examine the potential connection between this medication and severe anxiety.
Hydrochlorothiazide and General Nervous System Effects
The official listing for hydrochlorothiazide does not include “panic attack” as a direct side effect, but the medication can cause known nervous system disturbances. These documented side effects manifest as physical sensations that mimic a panic episode, including restlessness, vertigo, and dizziness, especially while the body adjusts to the medication.
Other reported effects are lightheadedness and weakness. These physical symptoms, such as feeling unsteady or having a rapid heart rate, can be misinterpreted as signs of danger. This misinterpretation initiates the fight-or-flight response, which is the physiological basis for a panic attack, inadvertently creating conditions for an anxiety spiral.
Electrolyte Imbalance and Anxiety
The most likely mechanism linking HCTZ to severe anxiety is its effect on the body’s fluid chemistry. As a diuretic, HCTZ increases the excretion of key electrolytes, notably potassium (hypokalemia) and sodium (hyponatremia). These minerals are essential for proper nerve signaling and muscle function throughout the body.
Hyponatremia (low sodium) directly affects the central nervous system, causing symptoms like confusion, irritability, fatigue, and anxiety. Hypokalemia (low potassium) causes physical distress, including muscle cramps, weakness, and an abnormal or fast heartbeat.
An irregular or fast heart rhythm is often the precise trigger for a full-blown panic attack. These imbalances create a cascade of physical symptoms—palpitations, muscle twitching, and confusion—that the brain registers as an emergency. This intense physical reaction can be indistinguishable from a panic attack.
Next Steps When Experiencing Symptoms
If you experience new or worsening anxiety, palpitations, or lightheadedness while taking hydrochlorothiazide, contact your prescribing physician immediately. Never stop taking a prescribed blood pressure medication suddenly. Abruptly discontinuing an antihypertensive drug can lead to a dangerous rebound spike in blood pressure.
Your doctor can determine if the symptoms are medication-related by ordering a blood test to check electrolyte levels. If an imbalance is detected, the physician may adjust the dosage, recommend a potassium supplement, or switch you to a different class of medication. Open communication is the most effective way to manage these potential side effects.