Long-term lithium and estimated glomerular filtration rate - Authors' reply

Glomerular filtration rate (GFR) can be estimated from serum creatinine using the modification of diet in renal disease (MDRD) formula or the chronic kidney disease–epidemiology collaboration (CKD–EPI) equation. Both methods are widely used in clinical practice to assess kidney function and guide treatment decisions.The MDRD equation does not require weight or height measurements and is normalized to the body surface area of 1.73 m², considered the average adult surface area.

The glomerular filtration rate (GFR) is a critical indicator of kidney health, reflecting how well the kidneys filter blood. Changes in GFR can signal potential kidney impairment, necessitating accurate measurement methods to monitor kidney function effectively.Various molecules can serve as markers for GFR measurement, with the ideal marker meeting several specific criteria. It must freely filter at the glomerulus, avoid reabsorption or secretion by the renal tubules, remain unmetabolized, not...

In geriatric patients, renal physiology undergoes significant changes, including diminished renal blood flow and a lower glomerular filtration rate (GFR), leading to alterations in medication clearance. Drugs such as aminoglycoside antibiotics, lithium, and digoxin, which rely on glomerular filtration for removal from the body, particularly impact pharmacokinetics. These drugs tend to have slower clearance rates in older adults, necessitating careful dosage considerations.Evaluation of renal...

The kidney serves as the primary organ responsible for eliminating drugs and their metabolites from the body. This process, known as renal elimination, starts with glomerular filtration and results in urine formation. Each kidney houses millions of functional units called nephrons, where urine production occurs. A nephron has two main components: a renal corpuscle and a renal tubule.
Drugs gain access to the kidney via the renal artery, which progressively branches off into afferent arterioles....

The Glomerular Filtration Rate (GFR) is a measure of kidney function, reflecting the volume of filtrate formed per minute in the kidneys. On average, GFR is approximately 125 mL/min in males and 105 mL/min in females. Maintaining a relatively constant GFR is essential for the kidneys to effectively regulate body fluid homeostasis and maintain extracellular stability.
GFR regulation involves two primary intrinsic controls: the myogenic and tubuloglomerular feedback mechanisms.
The myogenic...

The glomerular filtration rate (GFR) is a critical marker of kidney function, reflecting the efficiency of filtration by the glomeruli. Renal clearance of specific substances, such as inulin or creatinine, is commonly used to measure GFR.
Renal clearance refers to the volume of plasma cleared of a specific substance, such as creatinine, per unit of time. To measure clearance, urine samples are collected over a 24-hour period during each bladder voiding, followed by a single blood sample at the...