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Osmoprep

sodium phosphate
Used for Constipation, Colon Cleansing
Used for Constipation, Colon Cleansing

OsmoPrep (sodium phosphate) is a bowel prep that's used to clean out your bowel before a procedure called colonoscopy. A full course of treatment consists of 32 tablets that you take by mouth, but it's divided into two separate doses. Some people might prefer OsmoPrep (sodium phosphate) over liquid bowel prep solutions because even though they have to take a lot of tablets, the taste of the tablets is more tolerable compared with that of the liquids.

Last reviewed on February 4, 2022
basics-icon

What is OsmoPrep (sodium phosphate)?

What is OsmoPrep (sodium phosphate) used for?

  • Cleansing the colon to prepare for colonoscopy

How OsmoPrep (sodium phosphate) works

OsmoPrep (sodium phosphate) is a medication that help clean out your bowel. It belongs to a class called osmotic laxatives, which work by pulling water from your tissues into your colon to make it easier to pass stools.

Are you looking for information on Suprep (sodium sulfate / potassium sulfate / magnesium sulfate) instead?

Drug Facts

Common BrandsOsmoprep
Drug ClassOsmotic laxative
Controlled Substance ClassificationNot a controlled medication
Generic StatusNo lower-cost generic available
AvailabilityPrescription only
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Avg retail price
$325.55(save 15.76%)
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$274.23
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What are the side effects of OsmoPrep (sodium phosphate)?

The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.

Common Side Effects

  • Bloating (31%)
  • Nausea (26%)
  • Stomach pain (23%)

Other Side Effects

  • Vomiting

Serious Side Effects

Contact your healthcare provider immediately if you experience any of the following.
  • Sudden kidney problems: weakness, drowsiness, urinating less than normal, swelling of ankles, feet, and legs
  • Electrolyte imbalance(changes in body fluid and blood salts): vomiting, dizziness, urinating less than normal, fast heart rate, fast breathing, headache, fainting, or lack of energy
  • Bowel damage: severe stomach pain, rectal bleeding
  • Irregular heartbeat
  • Seizures
  • Gagging or choking

Source: DailyMed

The following side effects have also been reported

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

More common

Bloating

stomach pain

Incidence not known

Agitation

bloody or cloudy urine

burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings

confusion

cough

decrease in the frequency or amount of urine

decreased awareness or responsiveness

depression

difficult or labored breathing

difficult or painful urination

difficulty with swallowing

dizziness

fainting

fast, slow, or irregular heartbeat

headache

hives, itching, skin rash

hostility

increased blood pressure

increased thirst

irritability

large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or genitals

loss of appetite

loss of consciousness

lower back or side pain

muscle twitching

nausea

noisy breathing

puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue

rapid weight gain

redness of the skin

seizures

severe sleepiness

sudden decrease in the amount of urine

swelling of the face, ankles, or hands

tightness in the chest

unusual drowsiness, dullness, tiredness, weakness, or feeling of sluggishness

vomiting

Get emergency help immediately if any of the following symptoms of overdose occur:

Symptoms of overdose

Blurred vision

chest pain or discomfort

decreased frequency of urine

dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position

dry mouth

increase in heart rate

increased thirst

lightheadedness

loss of appetite

lower back or side pain

muscle cramps in the hands, arms, feet, legs, or face

muscle pain

pounding or rapid pulse

rapid breathing

restlessness

stomach cramps

sunken eyes

sweating

tremor

weakness

weight gain

wrinkled skin

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

pros-and-cons

Pros and cons of OsmoPrep (sodium phosphate)

thumbs-up

Pros

Doesn't have to be taken with other laxatives

Good option for people who don't like the taste of liquid bowel preps

Less chance of vomiting compared to mixed solutions for bowel prep

thumbs-down

Cons

Have to take a total of 32 tablets

Can be hard to take for people who have trouble swallowing

Only available as brand medication so it might be expensive

pharmacist-tips

Pharmacist tips for OsmoPrep (sodium phosphate)

pharmacist
  • If you feel very thirsty or if you're not making much urine, it might mean your body doesn't have enough fluids (dehydrated). Taking OsmoPrep (sodium phosphate) when you're dehydrated can lead conditions such as kidney damage. Make sure to drink enough water before starting OsmoPrep (sodium phosphate) to lower your chances of kidney damage.

    • OsmoPrep (sodium phosphate) bowel prep is made up of 2 dosages. You take one dose (20 tablets) the day before your colonoscopy. You take the second dose (12 tablets) the morning of your colonoscopy. Make sure you mark your calendars and set reminders of when you need to take your bowel prep.

      • Don’t take other oral medications within 1 hour of starting or finishing OsmoPrep (sodium phosphate) because this medication can lower the absorption of other medications.

        • Drink clear liquids, like water, before, during, and after taking OsmoPrep (sodium phosphate) to make sure your body has enough water.

          • Don’t eat or drink any alcohol, milk, anything with red or purple, or food with pulp because they can mess up your colonoscopy results.

            • Don’t take any other laxatives or enemas that have sodium phosphate while taking OsmoPrep (sodium phosphate) because doing so can raise your risk of getting kidney damage.

              • Let your provider know immediately if you vomit a lot or lose a lot of body fluids because this can cause your electrolytes to be out of balance. This can lead to serious side effects such as heartbeat problems or seizures.

                faqs

                Frequently asked questions about OsmoPrep (sodium phosphate)

                What can I eat before my colonoscopy procedure?
                On the day before the colonoscopy, eat a light breakfast before noon, which can include clear soup or plain yogurt. Don’t eat any solid foods on the day before your procedure. After breakfast, stay on a clear liquid diet until after the colonoscopy procedure.
                What does a clear liquid diet mean?
                You should be on a clear liquid diet starting at noon the day before your colonoscopy until after the procedure. This means you can eat or drink anything that is clear or colorless, such as water, clear broth soups, plain gelatin, or watered-down clear fruit juices without pulp. Don’t eat or drink any alcohol, milk, or anything colored red or purple because it can affect your colonoscopy results. If you're not sure about what you can eat, call your provider's office.
                Will my insurance cover OsmoPrep (sodium phosphate)?
                Since every insurance plan is different, check with your pharmacy after your provider writes a prescription for OsmoPrep (sodium phosphate). If this medication not covered by your insurance plan, talk to your provider about switching to a different medication for your procedure.
                How can I tell if OsmoPrep (sodium phosphate) is working correctly?
                OsmoPrep (sodium phosphate) produces bowel movements typically in 1 to 3 hours. Your bowel should start clearing out and the stools will start to become liquid. When your bowel prep is done, the stool should look mostly clear or have a light color without any solids. If you are still passing brown liquids or solids in your stools the morning of your procedure, let your provider know immediately.
                What happens if I throw up while taking OsmoPrep (sodium phosphate)?
                Let your provider know immediately if you threw up after taking OsmoPrep (sodium phosphate). They can let you know if you need to repeat your dose, take an alternative medication, or reschedule your procedure for a different date.
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                What are the risks and warnings for OsmoPrep (sodium phosphate)?

                OsmoPrep (sodium phosphate) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.

                risk-warning

                Sudden kidney damage

                • Risk factors: Older adult | Not enough fluids in your body | Bowel obstruction (blockage) | Colitis (bowel inflammation) | Kidney problems | Heart failure | Taking other medications that lower kidney function

                  Although rare, bowel preps that contain sodium phosphate, including OsmoPrep (sodium phosphate), have caused sudden kidney damage called acute phosphate nephropathy. This typically happens within days after taking OsmoPrep (sodium phosphate), but can sometimes happen months later. Sometimes, the damage is permanent and might require long-term dialysis treatment. You're at higher risk for kidney damage if you're also taking other medications that affect your kidneys, such as diuretics (water pills), angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs). It’s important to follow your provider’s directions on how to properly take this medication. Drink enough water before, during, and after taking OsmoPrep (sodium phosphate) to avoid getting dehydrated. Don’t take any other sodium phosphate medications or enema products with this bowel prep. Let your provider know right away if you feel tired, drowsy, have a hard time urinating, or have swelling in your legs and feet.

                  risk-warning

                  Loss of body fluids and electrolyte problems

                  • Risk factors: Kidney problems | Taking other medications that can affect electrolytes

                    OsmoPrep (sodium phosphate) can cause a lot of fluid loss (dehydration) and an imbalance in body salts (electrolytes). This can lead to problems such as abnormal heartbeat, seizures, and kidney problems. If you experience a lot of vomiting or signs of dehydration, let your provider know immediately. They might need to order lab work to check your electrolytes and kidney function.

                    risk-warning

                    Heartbeat problems

                    • Risk factors: Taking medications that affect heartbeat | Electrolyte not in balance | History of heart attack or heart failure

                      Although rare, OsmoPrep (sodium phosphate) might cause changes in your heartbeat because it can affect the balance of electrolytes in your body. Your risk of heart problems is higher if you're taking other medications that affect your heartbeat. If you have a history of heart problems, tell your provider before starting OsmoPrep (sodium phosphate) because they might need to check your heart before and after you use this medication.

                      risk-warning

                      Seizures

                      • Risk factors: Electrolytes not in balance | History of seizures | Taking other medications that raise your risk of seizures | Withdrawal from alcohol or certain medications

                        Taking OsmoPrep (sodium phosphate) can affect the balance of fluids and electrolytes in your body and can raise your risk for seizures, even if you've never had seizures before. Your risk is higher if you're also taking other medications that might cause seizures, such as tricyclic antidepressants. Be careful using this medication if you have a history of seizures. Get medical help right away if you feel like fainting.

                        risk-warning

                        Damage to your bowels

                        Osmotic laxatives, such as OsmoPrep (sodium phosphate), can cause damage in your bowels. Let your provider know if you have stomach ulcers, blockage, or inflammation before taking OsmoPrep (sodium phosphate), and report any signs of severe stomach pain or blood in your stools.

                        risk-warning

                        Gagging or choking

                        If you have trouble swallowing or have problems with your gag reflex, let your provider know. Because you need to swallow many tablets and a lot of liquid with this bowel prep, this medication might put you at risk for gagging or choking. If you use OsmoPrep (sodium phosphate), you might need a caregiver or loved one to check on you as you take this medication in case you need medical attention. If you have trouble taking OsmoPrep (sodium phosphate), let your provider know as soon as possible.

                        dosage

                        OsmoPrep (sodium phosphate) dosage forms

                        The average cost for 32 tablets of 1.5g of OsmoPrep (sodium phosphate) is $274.23 with a free GoodRx coupon. This is 15.76% off the average retail price of $325.55.
                        tablet
                        Tablet
                        DosageQuantityPrice as low asPrice per unit
                        1.5g32 tablets$274.23$8.57

                        Typical dosing for OsmoPrep (sodium phosphate)

                        Each Osmoprep tablet contains 1.5 grams of sodium phosphate. To prep and empty your bowels before the colonoscopy, you'll need to take a total of 32 Osmoprep tablets, divided into two doses.

                        Dose 1: Evening before your colonoscopy (20 tablets total)

                        • Take 4 tablets by mouth with 8 ounces of clear liquids every 15 minutes for a total of 20 tablets.

                        Dose 2: The day of your colonoscopy (12 tablets total)

                        • Starting 3 to 5 hours before colonoscopy, take 4 tablets by mouth with 8 ounces of clear liquids every 15 minutes for a total of 12 tablets.

                        interactions

                        Interactions between OsmoPrep (sodium phosphate) and other drugs

                        OsmoPrep (sodium phosphate) may interact with certain medications or supplements. Always let your doctor and pharmacist know about any other medications or supplements (including prescribed and over-the-counter medications, vitamins, and dietary or herbal supplements) that you are currently taking. The list below does not include all possible drug interactions with OsmoPrep (sodium phosphate). Please note that only the generic name of each medication is listed below.

                        Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.

                        Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

                        Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

                        • Aluminum Carbonate, Basic
                        • Aluminum Hydroxide
                        • Aluminum Phosphate
                        • Calcium Acetate
                        • Calcium Carbonate
                        • Calcium Citrate
                        • Dihydroxyaluminum Aminoacetate
                        • Dihydroxyaluminum Sodium Carbonate
                        • Magaldrate
                        • Magnesium Carbonate
                        • Magnesium Hydroxide
                        • Magnesium Oxide
                        • Magnesium Trisilicate
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                        How much does OsmoPrep (sodium phosphate) cost?

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                        contraindications-icon

                        OsmoPrep (sodium phosphate) contraindications

                        Contraindications are specific health conditions or situations in which a person should not take a medication due to safety concerns. If you have any of the following conditions or if any of the following apply to you, let your healthcare provider know because OsmoPrep (sodium phosphate) will not be safe for you to take.
                        • History of acute phosphate nephropathy (sudden kidney problem caused by phosphate products)

                        • Gastrointestinal (GI) obstruction (stomach block)

                        • Gastric bypass or stapling surgery

                        • Bowel perforations (opening in the wall of your intestine)

                        • Toxic colitis (severely inflamed colon)

                        • Toxic megacolon (very dilated intestine)

                        alternatives

                        What are alternatives to OsmoPrep (sodium phosphate)?

                        There are a number of medications that your doctor can prescribe in place of OsmoPrep (sodium phosphate). Compare a few possible alternatives below.
                        OsmoPrep (sodium phosphate)
                        Used for:
                        • Cleansing the colon to prepare for colonoscopy

                        $274.23 Lowest GoodRx priceView Prices
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                        $145.09 Lowest GoodRx priceView Prices
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                        $12.46 Lowest GoodRx priceView Prices

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