Alternatives to Sodium Phosphate If You Can't Fill Your Prescription

OsmoPrep (sodium phosphate, dibasic/sodium phosphate, monobasic) is an effective colonoscopy prep — but it's not the only one. If your pharmacy doesn't have it, or if your doctor has determined it's not safe for you due to kidney issues or other conditions, you have several solid alternatives. The good news: many of them are easier to find and some are actually preferred by gastroenterologists for certain patients.

Why Might You Need an Alternative to Sodium Phosphate?

There are two main reasons patients end up looking for an alternative to OsmoPrep:

Availability: OsmoPrep is a brand-name product stocked in limited quantities at many pharmacies. When it's out of stock — especially with a colonoscopy approaching — an alternative may be your fastest path forward.

Medical contraindications: Sodium phosphate carries a boxed warning for acute phosphate nephropathy (serious kidney damage). Patients over 55, those with kidney disease, heart failure, dehydration, bowel obstruction, or active colitis are often directed to use an alternative prep that doesn't carry the same risks.

Alternative 1: GoLYTELY / NuLYTELY (Polyethylene Glycol)

GoLYTELY and NuLYTELY are PEG (polyethylene glycol)-based preps. They're considered the gold standard for colonoscopy prep and are widely stocked at virtually every pharmacy. NuLYTELY is a sulfate-free version that many patients find slightly easier to drink.

Format: Powder mixed with water — up to 4 liters of liquid

Best for: Patients with kidney disease, heart failure, or elderly patients who cannot safely use sodium phosphate

Drawback: Large volume (4L); salty taste; patients often rate tolerability lower than tablet options

Cost: Very affordable — as low as $5–$15 with a GoodRx coupon for generic versions

Alternative 2: MoviPrep (Low-Volume PEG)

MoviPrep is a lower-volume PEG prep using only 2 liters of solution plus additional clear liquid. It contains PEG-3350, electrolytes, and ascorbate. Research shows it has high patient tolerability and is one of the better-rated preps compared to GoLYTELY.

Format: Two 1-liter doses of solution plus additional clear liquid

Best for: Patients who want a lower-volume prep without using sodium phosphate

Cost: More expensive than GoLYTELY; typically $40–$80 with coupons

Alternative 3: SUTAB (Sodium Sulfate Tablets)

SUTAB was FDA-approved in 2020 and is a tablet-based prep like OsmoPrep — but it uses sodium sulfate instead of sodium phosphate. This eliminates the risk of acute phosphate nephropathy. Patients who want the convenience of tablets but can't use OsmoPrep due to kidney concerns often find SUTAB to be an excellent alternative. The total tablet count is 24 (vs. 32 for OsmoPrep), and tolerability is generally well-rated.

Format: 24 oral sulfate tablets in two doses with minimum 3 liters water total

Best for: Patients who prefer tablets over liquid but need a safer alternative to sodium phosphate

Cost: Typically $40 or less with manufacturer coupon for insured patients

Alternative 4: Suprep (Sodium Sulfate Solution)

Suprep is a liquid-based prep that uses sodium sulfate, potassium sulfate, and magnesium sulfate. It's lower volume than GoLYTELY and does not carry the same kidney risks as sodium phosphate. Studies show it has high effectiveness and generally better tolerability than GoLYTELY.

Format: Two 6-oz bottles mixed with water; total fluid intake approximately 3 liters

Best for: Patients who want a lower-volume option without sodium phosphate or PEG

Alternative 5: MiraLAX + Gatorade (OTC Combination)

The MiraLAX-and-Gatorade combination is an OTC option widely used in clinical practice, though it is not FDA-approved as a colonoscopy prep. It consists of a 238-gram bottle of MiraLAX mixed into 64 oz of Gatorade (not red or purple), often combined with Dulcolax (bisacodyl) tablets. Patients rate its tolerability highly and it's among the least expensive options. Your doctor must guide you on the specific protocol.

Format: MiraLAX powder in Gatorade; OTC and widely available

Cost: Typically under $20 total; no prescription needed for the prep ingredients (Dulcolax may need a prescription in some cases)

Alternative 6: Clenpiq (Sodium Picosulfate)

Clenpiq is a low-volume liquid prep containing sodium picosulfate, magnesium oxide, and citric acid. It comes in two small 160-mL bottles and requires drinking additional clear liquids. Many patients find the low volume and pleasant taste a real plus. It is not recommended for patients with severe kidney impairment.

Which Alternative Should You Choose?

The right alternative depends on your health history, what's available at a pharmacy near you, and your insurance coverage. Always ask your gastroenterologist or prescriber before switching — they need to approve any change. Most preps can be substituted without rescheduling your colonoscopy as long as you complete the new prep correctly.

If you'd rather stick with OsmoPrep and need help finding it, medfinder can call pharmacies near you to find which ones have it in stock. Or, read our guide on how to find sodium phosphate in stock near you for more strategies.