Lasix Does Not Directly Cause Shivering, But Can Cause Tachycardia Through Volume Depletion
Lasix (furosemide) is not recognized as a direct cause of shivering, but tachycardia is a well-documented adverse effect, particularly when excessive diuresis leads to fluid and electrolyte depletion.
Tachycardia as a Recognized Side Effect
The FDA drug label explicitly lists tachycardia as a sign of fluid or electrolyte imbalance that should be monitored in all patients receiving Lasix therapy 1. This occurs through several mechanisms:
Primary Mechanisms of Furosemide-Induced Tachycardia:
- Volume depletion: Excessive diuresis reduces blood volume, triggering compensatory tachycardia to maintain cardiac output 1
- Electrolyte disturbances: Hypokalemia and hypomagnesemia can predispose to arrhythmias and tachycardia 2, 3
- Reflex sympathetic activation: Blood volume reduction activates compensatory mechanisms that increase heart rate 4
Clinical Evidence:
Research demonstrates that furosemide's effect on heart rate varies with the degree of volume loss. When blood volume reduction exceeds approximately 5%, heart rate significantly increases at higher work intensities 4. Additionally, continuous furosemide infusions have been associated with supraventricular tachycardia in pediatric cardiac surgery patients, particularly when diuresis is brisk (8-10 ml/kg/hr) 5.
In acute myocardial infarction patients, high-dose furosemide prophylaxis (120 mg in 24 hours) resulted in increased heart rates and more frequent supraventricular tachyarrhythmias compared to low-dose therapy 6.
Shivering: Not a Documented Side Effect
Shivering is not listed in the FDA drug label or major clinical guidelines as an adverse effect of furosemide 1. The documented adverse effects include:
- Electrolyte depletion (hypokalemia, hyponatremia, hypomagnesemia)
- Hypotension
- Azotemia
- Rashes
- Hearing difficulties (with very high doses)
- Arrhythmias
However, one isolated case report mentions "flushing, sweating attacks, restlessness, nausea, increase in blood pressure, and tachycardia" when furosemide was given intravenously within 24 hours of chloral hydrate administration 1. This is not shivering per se, and represents a specific drug interaction rather than a direct effect of furosemide.
Clinical Monitoring Recommendations
All patients receiving Lasix should be monitored for signs of fluid or electrolyte imbalance, including tachycardia 1. The ACC/AHA guidelines emphasize that excessive diuretic use can decrease blood pressure and impair renal function, with hypotension and tachycardia serving as warning signs 2.
Key Monitoring Parameters:
- Heart rate and blood pressure
- Serum electrolytes (particularly potassium and magnesium)
- Renal function (creatinine, BUN)
- Daily weights
- Signs of volume depletion (oliguria, hypotension, tachycardia)
Important Caveat:
If a patient presents with both shivering and tachycardia while on furosemide, consider alternative explanations such as:
- Infection/sepsis
- Thyroid dysfunction
- Anxiety or withdrawal states
- Other medications
- Underlying cardiac arrhythmias unrelated to furosemide
The tachycardia may be furosemide-related through volume depletion, but the shivering requires investigation for other causes.