Readi-Cat 2 Side Effects | What Most Patients Notice

Most people get brief stomach upset or constipation after oral barium; rare reactions include allergy, breathing trouble, or bowel blockage.

Readi-Cat 2 is an oral barium sulfate contrast used for certain CT scans of the abdomen. You drink it so the GI tract shows up clearly on imaging. For many patients, the rough part is the prep and the taste, not the contrast itself.

Side effects can still happen. Some are mild and pass the same day. A few are rare but serious and need fast care. This article lays out what can happen, what it tends to feel like, and what to do if something feels off.

What Readi-Cat 2 Is And Why Side Effects Happen

Readi-Cat 2 is a barium sulfate suspension. Barium isn’t absorbed into the bloodstream in normal use; it stays in the gut and exits in stool. That local action is one reason many people do fine with it. The flip side is that the thick liquid can slow bowel movement and cause bloating or cramps for a short time.

Most reactions fall into three buckets: (1) the gut getting irritated or slowed down, (2) a sensitivity reaction in a small number of people, or (3) a complication tied to an existing GI problem, like narrowing, blockage, or a weak spot in the bowel wall. The prescribing information lists these risk areas and the situations where extra screening matters. FDA prescribing information for READI-CAT 2 lists warnings and contraindications.

Readi-Cat 2 Side Effects In Real Life: What To Expect

Many people notice a full belly, mild cramps, nausea, or constipation later that day. Some get loose stools instead, especially if a laxative is part of the imaging prep. You may also see pale or white stools for a day or two because barium is light colored.

If you want the label wording in one place, the product page on DailyMed’s READI-CAT 2 listing summarizes reported reactions and safety warnings used in hospitals.

Common, Usually Mild Reactions

• Constipation later the same day or the next day.
• Stomach cramps or a “gassy” feeling.
• Nausea, sometimes with a single vomit episode.
• Diarrhea or urgency, often tied to prep instructions.
• Temporary stool color change (pale/white) for a short time.

Less Common Reactions People Still Report

Some people feel weak, sweaty, or light-headed around the time of the scan. Fasting, stress, and drinking a larger volume can all play a part. If you get shaky when you skip meals, tell the imaging team before you start.

Rare Reactions That Need Fast Attention

Serious events are uncommon, but they’re the reason radiology teams ask screening questions. Warning signs can include hives, swelling of the face or throat, wheezing, severe belly pain that keeps building, no bowel movement or gas by the next day, repeated vomiting, or blood in stool.

For a patient-friendly list of “get help now” symptoms linked to oral barium, MedlinePlus’ barium sulfate page lists reactions people are told to report.

Side Effect Details With Practical Next Steps

This section gets specific. It tells you what each reaction tends to feel like, what you can try at home, and when it’s smarter to call the imaging center or seek urgent care.

Constipation And Stool Changes

Constipation is the side effect people talk about most. Barium is thick and can slow movement in the bowel, especially if you were already dehydrated from fasting. Stool may look pale or chalky until the barium clears.

Many people improve with water, warm drinks, and normal meals once allowed. If your site gave you a laxative plan, follow their timing. If you have no bowel movement or can’t pass gas the day after the scan, call the imaging team.

Nausea, Vomiting, And Stomach Cramps

Nausea is often short-lived and tied to volume, taste, or drinking too quickly. Slow, steady sips can help if your instructions allow it. If you vomit and can’t keep the contrast down, tell the staff right away so they can adjust the plan.

Diarrhea Or Urgency

Some people get loose stools. That can come from prep meds, sweeteners, or a gut reaction to the suspension. Mild diarrhea that settles quickly is usually not a problem. Ongoing watery stools paired with dizziness, dry mouth, or dark urine can signal dehydration, so push fluids if you’re allowed to drink after the scan.

Allergic-Type Reactions

Barium sulfate itself isn’t absorbed, yet products can contain flavoring agents and other ingredients that some people react to. Allergic-type reactions can show up as hives, itching, rash, swelling, hoarseness, or trouble breathing. Treat that as urgent. Tell staff on site, or seek emergency care if you’re already home and breathing feels tight.

Aspiration Into The Lungs

Aspiration means liquid goes into the airway while swallowing. It’s more likely if you have swallowing problems, altered alertness, or a high vomiting risk. If you choke badly during the drink, keep coughing, or feel short of breath after, alert staff right away.

Bowel Blockage, Impaction, Or Perforation

These are rare, but they’re the scenarios clinicians watch for. Barium can harden, especially with dehydration, and form a plug. It can also worsen a partial blockage that was already there. If there is a known or suspected tear in the GI tract, barium in the wrong place can cause severe harm, which is why the label lists it as a “do not use” situation.

Signs that need urgent assessment include swelling or severe belly pain that climbs, repeated vomiting, fever, fainting, blood in stool, or no gas and no stool after the test.

For general safety notes on oral barium products written for patients, Mayo Clinic’s barium sulfate overview describes common reactions and cautions about how it’s given under medical supervision.

Table Of Symptoms, What They Often Mean, And What To Do

The table below helps you sort “normal and annoying” from “call now.” It’s not a diagnosis tool. It’s a practical triage map based on how oral barium reactions are described in official labeling and patient instructions.

What You Notice	What It Can Point To	What To Do Next
Pale or white stool for 1–2 days	Barium passing through	Drink fluids, resume meals as allowed, watch for return to normal color
Mild cramps or gas	Gut irritation or slowed movement	Walk a bit, sip water, eat lightly once cleared
Constipation for less than 24 hours	Temporary slow-down from barium	Increase fluids, follow site instructions on stool softener if given
No stool and no gas the next day	Impaction or worsening blockage	Call the imaging center or your clinician the same day
Repeated vomiting	Intolerance, dehydration risk	Contact the imaging team; seek urgent care if you can’t keep fluids down
Hives, face swelling, throat tightness	Allergic-type reaction	Seek emergency care; tell staff you took oral barium contrast
Choking during drink, new wheeze, short breath	Aspiration into airway	Tell staff right away; urgent evaluation may be needed
Severe belly pain, fever, blood in stool	Serious GI complication	Go to urgent care or emergency department

Who Should Flag Their History Before Drinking It

Most adults and children can take oral barium safely when the team screens for red flags. Some histories raise the odds of trouble. The imaging team may change the plan or pick a different contrast.

GI Issues That Can Raise Risk

• Known or suspected bowel blockage or severe narrowing.
• Known or suspected perforation of the GI tract.
• Severe constipation, slow motility, or prior impaction.
• Active bowel inflammation with severe belly tenderness.
• Recent GI surgery where healing tissue is still fragile.

Swallowing Or Breathing Concerns

• Trouble swallowing or frequent choking with drinks.
• High aspiration risk from neurologic conditions or weak cough.
• Severe reflux with repeated vomiting.

Medication And Hydration Factors

Dehydration makes constipation and impaction more likely. If you’re on a diuretic, have kidney disease, or you’re older and get dehydrated easily, tell the team. If they ask you to fast, ask what fluids are still allowed and when you can drink again after the scan.

What To Do Before, During, And After The Scan

Most mild side effects are easier to avoid than to treat. A few small choices around timing, hydration, and pacing the drink can make the day smoother.

Before You Arrive

• Read the prep sheet early so fasting instructions don’t catch you off guard.
• If you tend to get constipated, ask whether a stool softener plan is expected after the test.
• Bring a list of allergies, past contrast reactions, and GI surgeries.

While You Drink The Contrast

• Drink at the pace your staff asks for. If nausea hits, pause and tell them.
• If you start coughing or choking, stop drinking and alert staff right away.
• Ask if you can rinse your mouth or take small sips of water after each dose.

After The Scan

• Drink water through the rest of the day unless your clinician told you not to.
• Eat a normal meal when cleared. Fiber can help stool move along.
• Expect lighter stool color for a short time.
• Call the imaging center if you have severe pain, repeated vomiting, rash, swelling, or no bowel movement by the next day.

Table Of Timing: What’s Normal, What’s Not, And When To Call

Timing is a big clue. Mild gut upset right after the drink is common. Symptoms that get worse over hours, or that block stool and gas, need attention.

Time After The Scan	Often Normal	Call Or Seek Care If
0–6 hours	Full feeling, mild cramps, mild nausea	Breathing trouble, severe swelling, repeated vomiting
6–24 hours	Pale stool, mild constipation, mild diarrhea	Severe belly pain, fever, blood in stool
24–48 hours	Stool color returning to normal	No stool and no gas, worsening bloating, ongoing vomiting
48+ hours	Back to baseline bowel pattern	Constipation that won’t budge, new weakness, signs of dehydration

A Simple After-Scan Checklist

This checklist keeps you focused on the few signals that matter most after you leave the imaging center.

• Drink extra water across the day.
• Notice your stool pattern and whether you can pass gas.
• Watch for rash, hives, swelling, or breathing changes.
• Pay attention to belly pain that keeps building instead of easing.
• Follow any laxative or diet plan your clinic gave you.