Understanding Osp Laxatives: How Do They Work?

Oral sodium phosphate (OSP) is a laxative used for bowel cleansing before colonoscopy or other medical procedures. It is the most commonly used osmotic laxative for colonic and gynecological surgery. OSP works by causing fluid loss, so patients are advised to drink large quantities of clear liquids during the bowel preparation. However, OSP has been associated with serious adverse effects, including acute phosphate nephropathy, a type of acute renal failure. This condition can lead to kidney failure and has been observed in patients with impaired renal function, dehydration, or electrolyte abnormalities. It is important for patients to be aware of the risks associated with OSP and to consult a healthcare professional before use.

OSP laxatives are used for bowel cleansing before a colonoscopy or other medical procedures

Oral sodium phosphate (OSP) products are used for bowel cleansing prior to a colonoscopy or other medical procedures. OSPs are available both with and without a prescription and are taken by mouth.

The laxatives work by making bowel movements frequent, loose, and runny, and they do this by causing fluid loss. Therefore, it is recommended that patients drink large quantities of clear liquids as part of the bowel preparation.

The U.S. Preventive Services Task Force (USPSTF) recommends that clinicians screen men and women aged 50 and above for colorectal cancer using one of several tests, including a colonoscopy. Colon cancer is treatable when detected early, and the best treatment is to identify and remove precancerous polyps before they progress to cancer. A high-quality and safe colon cleansing preparation is important for colon cancer screening using colonoscopy.

However, it is important to note that there are some risks associated with the use of OSPs. The FDA has issued a warning about a possible sudden loss of kidney function or acute kidney injury, as well as blood mineral disturbances, for patients with chronic kidney disease (CKD) who use bowel cleansing products. This condition is called acute phosphate nephropathy and is caused by phosphate crystal deposition in the kidneys.

Other adverse reactions or quality problems experienced with the use of OSP products may be reported to the FDA's MedWatch Adverse Event Reporting program.

OSP can cause hyperphosphatemia and hypocalcemia due to excessive absorption of phosphates

Oral sodium phosphate (OSP) is a laxative used for colon cleansing before colonoscopy or other medical procedures. OSP is the most commonly used osmotic laxative for this purpose due to its small volume and good tolerance.

However, OSP can cause hyperphosphatemia and hypocalcemia due to excessive absorption of phosphates. Hyperphosphatemia is when there are abnormally high serum phosphate levels, and it can be caused by increased phosphate intake, decreased phosphate excretion, or a shift of phosphate from intracellular to extracellular space. Hypocalcemia is when there are abnormally low levels of ionized calcium.

In a study of 100 low-risk patients who were administered OSP, 87% developed hyperphosphatemia, with the highest serum phosphate level recorded being 9.6 mg/dL. The study also found that hyperphosphatemia was inversely correlated with body weight, suggesting that OSP-induced hyperphosphatemia is related to body weight.

The serious adverse effects of OSP have led to the withdrawal of some OSP products from the market. It is recommended to perform a preoperative evaluation to avoid administering OSP laxatives to patients at risk, reduce the dose for low-weight patients, and ensure adequate oral intake of clear liquids to avoid dehydration.

There have been reports of deaths and irreversible dialysis-requiring renal insufficiency caused by OSP

Oral sodium phosphate (OSP) is an osmotic laxative commonly used for colon cleansing before colonoscopies and other medical procedures. While generally well-tolerated due to its small volume, OSP can induce hyperphosphatemia and hypocalcemia due to excessive phosphate absorption. This has been linked to reports of deaths and irreversible renal insufficiency requiring dialysis.

Hyperphosphatemia, or elevated serum phosphate levels, is a serious condition that can have life-threatening consequences. In the context of OSP usage, it is often associated with conditions that increase intestinal phosphate absorption or hinder its elimination. These conditions include ulcerative colitis, Crohn's disease, ischemic colitis, kidney disease, dehydration, and aging. Additionally, an overdose of OSP (greater than 60g) can lead to hyperphosphatemia.

The risk of hyperphosphatemia is particularly prominent in patients with pre-existing renal insufficiency or kidney disease. OSP use in these patients can lead to acute phosphate nephropathy, a condition characterized by phosphate crystal deposition in the kidneys, resulting in sudden loss of kidney function and potential kidney failure. This is especially pertinent for individuals with chronic kidney disease (CKD), as highlighted by an FDA warning.

The fatal outcomes associated with OSP-induced hyperphosphatemia are primarily attributed to arrhythmia or heart attacks triggered by electrolyte imbalances and dehydration. These severe complications underscore the necessity of careful patient selection and diligent monitoring of kidney function, especially for those at high risk.

To mitigate the risks associated with OSP usage, it is recommended to perform preoperative evaluations to identify patients who may be at risk for adverse effects. For patients with low body weight, reducing the dose of OSP is advised. Additionally, maintaining adequate hydration by consuming sufficient clear liquids is crucial to prevent dehydration and its associated complications.

OSP products are available both with and without a prescription

Oral sodium phosphate (OSP) products are used for bowel cleansing before a colonoscopy or other medical procedures. They are osmotic laxatives that work by making bowel movements frequent, loose, and runny. This is achieved by causing fluid loss, so it is recommended that patients drink large quantities of clear liquids during bowel preparation. OSP products are available both with and without a prescription.

Visicol® and OsmoPrep® are OSP products that are available by prescription only. Other similar OSP products are non-prescription and can be used as a laxative at low doses. However, due to a recent warning by the FDA regarding the risk of acute phosphate nephropathy, non-prescription OSP products should only be used as laxatives and not for bowel cleansing. The FDA suggests that consumers get a prescription from a healthcare professional when considering a bowel cleansing procedure.

The possible risks associated with the use of OSP products include hyperphosphatemia and hypocalcemia due to excessive absorption of phosphates. There have also been reports of deaths and irreversible dialysis-requiring renal insufficiency. The risk of these adverse reactions is higher in certain patient groups, including those with dehydration, bowel obstruction, delayed bowel emptying, or active colitis. Additionally, those taking certain medications, such as diuretics, angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), and nonsteroidal anti-inflammatory drugs (NSAIDs), are also at increased risk.

It is important to note that children under 18 years of age should not use OSP products alone or in combination with other laxatives containing sodium phosphate. Furthermore, patients with chronic kidney disease (CKD) who use bowel cleansing products should be aware of the recent FDA warning regarding the risk of acute kidney injury and blood mineral disturbances.

OSP is not suitable for children under 18 or people with dehydration, bowel obstruction, or delayed bowel emptying

Oral sodium phosphates (OSPs) are a type of laxative commonly used for colon cleansing before colonoscopies and colonic and gynaecological surgeries. They work by causing fluid loss, leading to frequent, loose, and runny bowel movements.

While OSPs are effective in clearing the bowel, they are not suitable for everyone. OSPs are not recommended for children under 18 years old, even when used in combination with other laxatives containing sodium phosphate. This is because children's bodies and digestive systems are still developing, and the use of laxatives may interfere with their natural bowel function and have adverse effects on their health.

Additionally, OSPs are not suitable for individuals with dehydration. As OSPs work by causing fluid loss, using them in individuals who are already dehydrated can further deplete their fluid levels and lead to serious health complications. Dehydration can be assessed by observing symptoms such as an eagerness to drink, lethargy, cool and moist extremities, weak or absent radial pulse, and reduced or absent urine flow.

People with bowel obstruction or delayed bowel emptying are also advised against using OSPs. Bowel obstruction is a condition where the small or large intestine is partially or completely blocked, preventing the normal passage of stool. Since OSPs increase bowel movements, using them in individuals with bowel obstruction can worsen the condition and lead to potential intestinal damage. Delayed bowel emptying, also known as slow transit, is a condition where the movement of stool through the colon is slower than normal, leading to hard and dry stools. OSPs are not recommended in this case as they can further slow down the bowel movement and cause discomfort.

Frequently asked questions