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Key takeaways
Constipation is the most common side effect of sucralfate, but it is usually mild and manageable.
Serious reactions are rare, but allergic reactions, severe constipation, bezoar formation, or high blood sugar (liquid form) require medical attention.
Take sucralfate on an empty stomach and separate it from other medications to prevent drug interactions.
Sucralfate (generic Carafate) is used to treat ulcers and sometimes GERD. It works by forming a protective barrier over ulcers or inflamed tissue, allowing them to heal.
Most people tolerate sucralfate well. Side effects are uncommon and usually mild. Here’s what you should know.
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There are very few side effects of sucralfate
In clinical trials of more than 2,700 patients treated with sucralfate, less than 5% of participants experienced some form of side effects. Sucralfate side effects were mild and rarely led to discontinuation of the drug.
Constipation is the most common side effect
Constipation was the most common side effect, reported by only 2% of patients, according to the FDA. You may notice hard stools, straining, bloating, or cramping as your body adjusts to sucralfate.
RELATED: Home remedies for constipation
Other mild side effects
These occur in fewer than 0.5% of patients:
- Diarrhea
- Nausea
- Gas or indigestion
- Vomiting
- Dry mouth
- Itching or rash
- Dizziness
- Headache
- Trouble sleeping
- Back pain
These are usually temporary. If symptoms persist or are bothersome, let your provider know.
Serious side effects of sucralfate
Sucralfate has a few rare, but potentially serious side effects, including:
Signs of a severe allergic reaction (call 911):
- Hives
- Swelling of the face, lips, tongue, or throat
- Trouble breathing
Severe constipation or bowel blockage:
- Severe abdominal pain
- Vomiting
- Inability to pass stool or gas
Bezoar formation (rare):
This is a hard lump formed by undissolved medication particles, usually in the stomach. Symptoms can include:
- Severe stomach pain
- Nausea
- Vomiting
High blood sugar (oral suspension only):
The liquid form of sucralfate commonly contains sugar or sugar substitutes. Even if the amount of sugar per dose is relatively small, taking the medication three or four times daily every day can raise a person’s blood sugar. If you have diabetes, monitor your blood sugar closely and report unusual elevations.
How long do sucralfate side effects last?
- Mild effects like constipation often improve within days to weeks.
- Serious reactions require medical treatment.
- Call 911 immediately if you have signs of an allergic reaction.
- Bezoar formations may require removal during an upper endoscopy.
- Sucralfate does not cause long-term side effects after stopping the medication.
Who should use caution?
There are several contraindications for taking sucralfate, including hypersensitivity to any of the medication’s components. The benefits of treatment may outweigh the risks in certain patients.
Difficulty swallowing (dysphagia)
Sucralfate is contraindicated in patients with dysphagia without a known cause, a condition in which patients have difficulty swallowing. This is because sucralfate can form a mass in the esophagus if it isn’t completely dissolved before it reaches this area of the body.
On the other hand, dysphagia caused by acid reflux is a condition often treated with sucralfate.
GI obstruction
Patients with known GI obstruction, an intestinal blockage, shouldn’t take sucralfate. This medication can bind to food and other medications, worsening the obstruction if the material cannot pass through the intestine.
Renal impairment
Sucralfate is mainly excreted in the feces rather than through the kidneys. That said, this medication should be used with caution in patients who have known serious kidney disease, kidney failure, or who are on dialysis treatment, as it can lead to elevated aluminum levels in the blood.
Type 2 diabetes
Sucralfate in suspension form can affect blood sugar levels in patients with Type 2 diabetes. The medication has been reported to induce high blood sugar in some diabetic patients due to sugar or sugar substitutes being added to the suspension form. The amount of antidiabetic medication you take may need to be adjusted.
Aspiration risk
Sucralfate can increase the risk of pneumonia and other pulmonary complications in patients who are at increased risk for aspiration. Some conditions may affect the way a patient swallows or even prevent them from swallowing. In these cases, sucralfate should not be taken.
Use caution in those with a tracheostomy, recent intubation, history of aspiration, or difficulty swallowing.
Impaired gag reflex
Certain types of anesthesia, Parkinson’s disease, a history of stroke, or esophageal surgery may alter gag reflexes. Sucralfate is not recommended for patients with these conditions, as they are at increased risk of aspiration and bezoar formation.
Pregnancy and breastfeeding
Sucralfate is safe to take during pregnancy if clearly needed, according to the drug label. It is not known to cause birth defects and should be used during pregnancy only if the benefits outweigh the risks. Human studies show minimal drug absorption into the bloodstream.
Most providers consider sucralfate to be safe to use while breastfeeding since there is minimal drug absorption. While no human data is available, the medication poses a low risk to the infant when used during this time.
Mothers may need additional fluids while taking sucralfate to prevent constipation, which may occur with its use.
How to take sucralfate with other medications
It’s important to take sucralfate on an empty stomach and separate it from other medications by at least two hours (before or after). Do not take antacids within 30 minutes of sucralfate.
“[Sucralfate] should be separated from both other medications and also food, by at least one to two hours, making it quite difficult for some patients to incorporate it into their daily regimen,” says Jesse P. Houghton, MD, FACG, the senior medical director of gastroenterology at Southern Ohio Medical Center. “The reason for this need to separate sucralfate from medications and food is that, because it coats the stomach, it can prevent the absorption of anything ingested at the same time as the medication.”
Most common sucralfate interactions |
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|---|---|---|
| Medication | What Happens | Clinical Note |
| Xofluza (baloxavir marboxil) | Sucralfate decreases baloxavir absorption | May reduce antiviral effectiveness |
| Deferasirox | Sucralfate decreases deferasirox absorption | May reduce iron chelation effectiveness |
| Naproxen | Sucralfate binds naproxen in the GI tract | Can reduce pain-relief effect |
| Potassium phosphate / Sodium phosphate | Binding reduces phosphate levels absorbed | May weaken therapeutic effect |
| Tetracycline and related antibiotics | Sucralfate binds tetracycline in the stomach | May cause antibiotic treatment failure |
| Digoxin | Sucralfate decreases digoxin absorption | May reduce heart-failure and arrhythmia control |
| Cimetidine | Gastric binding lowers drug absorption | May reduce acid-reduction effect |
| Ketoconazole | Requires acidic environment; sucralfate interferes | May reduce antifungal effectiveness |
| Levothyroxine | Sucralfate binds thyroid hormone | Can cause undertreated hypothyroidism |
This is not a complete list of drug interactions (see more here). Always give your doctor and pharmacist a full list of everything you take.
Tips to reduce side effects
- Give your doctor a full list of your medical conditions and medications.
- Take sucralfate exactly as prescribed.
- Take it on an empty stomach at least two hours before or after a meal or medication.
- Do not crush sucralfate tablets (unless directed otherwise). Swallow tablets whole with enough water to ensure they’re completely swallowed.
- Shake the liquid well before measuring using the dosing syringe or cup provided with the medication. Do not use a household spoon.
- Stay well hydrated to reduce risk and severity of constipation.
- Take a missed dose as soon as possible. Do not double doses if you miss one.
- Do not stop early just because symptoms improve. Ulcers need the full treatment course (often six to eight weeks) to heal completely.
When to call your doctor
Contact your provider if you have:
- Severe or persistent constipation
- Ongoing nausea or vomiting
- High blood sugar (if diabetic)
- Any unusual or worsening symptoms
Call 911 for signs of a serious allergic reaction.
Expert takeaway
“I, like many other gastroenterologists, find sucralfate to be an invaluable component of treating peptic ulcer disease and GERD, especially when either of these conditions has been refractory to conventional treatment with a PPI (proton pump inhibitor). The main obstacle to patient adherence is the difficult schedule of administration. Sucralfate is typically given three and even four times daily. As you can imagine, taking any medication four times daily can be difficult. Combine that with the need to separate the medication from other prescription and OTC medications and food throughout the day, and you can see how patients may struggle with this schedule,” says Jesse P. Houghton, MD, FACG, a member of the SingleCare Medical Review Board
- Carafate drug label, FDA
- Sucralfate, StatPearls (2024)
- Sucralfate, Drugs and Lactation Database (LactMed) (2021)