Colazid (Balsalazide Disodium)

What Is Colazid and What Is It Used For?

Colazid (balsalazide disodium) is an aminosalicylate (5-ASA) anti-inflammatory medicine used to treat ulcerative colitis, a chronic inflammatory bowel disease that causes inflammation and ulcers in the lining of the large intestine. It is available as 750 mg hard capsules for oral use and requires a prescription.

Colazid belongs to a class of medications known as aminosalicylates, which are the first-line treatment for mild-to-moderate ulcerative colitis according to guidelines from the British Society of Gastroenterology (BSG), the American Gastroenterological Association (AGA), and the European Crohn's and Colitis Organisation (ECCO). The active ingredient, balsalazide disodium, is a prodrug that is designed to deliver mesalazine (also known as 5-aminosalicylic acid or 5-ASA) directly to the colon.

Unlike some other mesalazine preparations that may be partially absorbed in the upper gastrointestinal tract, balsalazide passes through the stomach and small intestine essentially intact. When it reaches the colon, bacteria naturally present in the large intestine contain enzymes called azoreductases that cleave the azo bond in the balsalazide molecule, releasing the active mesalazine and an inert carrier molecule called 4-aminobenzoyl-beta-alanine. This targeted delivery mechanism ensures that the anti-inflammatory drug reaches the site of disease in high concentrations.

Mesalazine works locally on the colonic mucosa (the inner lining of the large intestine) through several mechanisms. It inhibits the cyclooxygenase and lipoxygenase pathways, which are responsible for producing pro-inflammatory prostaglandins and leukotrienes. It also acts as a scavenger of reactive oxygen species (free radicals) that contribute to tissue damage in ulcerative colitis. Additionally, mesalazine may inhibit the nuclear factor kappa-B (NF-kB) signalling pathway, a key regulator of inflammatory gene expression.

Colazid is used in two main clinical settings. First, it is prescribed for the treatment of active ulcerative colitis – when patients are experiencing a flare with symptoms such as bloody diarrhea, abdominal pain, and urgency. Second, it is used as maintenance therapy to keep the disease in remission and prevent future flares. Clinical studies have demonstrated that aminosalicylates like balsalazide can maintain remission in approximately 40-50% of patients over a 12-month period, which is significantly better than placebo.

What Should You Know Before Taking Colazid?

Before starting Colazid, your doctor needs to know your complete medical history, current medications, and whether you have any allergies to salicylates. Blood and urine tests will be taken before treatment begins and at regular intervals during therapy to monitor your liver, kidney, and blood cell function.

Contraindications

You must not take Colazid if any of the following apply to you:

• Allergy to balsalazide disodium or any of the other ingredients in the capsules (including gelatin, magnesium stearate, colloidal anhydrous silica, shellac, titanium dioxide E171, and iron oxides E172)
• Allergy to mesalazine (5-aminosalicylic acid), acetylsalicylic acid (aspirin), or other salicylates – since balsalazide releases mesalazine in the colon, cross-reactivity is possible
• Severe liver disease – because impaired hepatic function may affect the processing and elimination of the drug
• Moderate or severe kidney impairment – as the kidneys play a role in eliminating mesalazine and its metabolites, and renal toxicity has been reported with aminosalicylates
• Pregnancy or breastfeeding – the safety of balsalazide has not been adequately established in pregnant or lactating women

Warnings and Precautions

Tell your doctor or pharmacist before taking Colazid if you have or have ever had any of the following conditions, as they may require special precautions or closer monitoring:

• Asthma – patients with asthma may be at increased risk of hypersensitivity reactions to salicylates, and bronchospasm has been reported
• Blood disorders – aminosalicylates can rarely cause changes in blood cell counts, including leucopenia (low white blood cells), agranulocytosis, and thrombocytopenia (low platelets)
• Mild kidney disease – even mild renal impairment warrants closer monitoring during treatment, as aminosalicylates have been associated with nephrotoxicity including interstitial nephritis
• Confirmed liver disease – hepatic function should be closely monitored as hepatitis and elevated liver enzymes have been reported
• Active peptic ulcer disease – the salicylate component may worsen gastric or duodenal ulcers

Monitoring During Treatment

Your doctor will order blood and urine tests before you start treatment with Colazid. These tests check your kidney function, liver function, and blood cell counts. During treatment, your doctor will continue to monitor these parameters at regular intervals. This is particularly important during the first few months of therapy, when the risk of adverse effects may be highest.

According to the BSG guidelines, patients on aminosalicylate therapy should have renal function monitored at baseline, at 3 months, at 12 months, and then annually. Full blood counts should be checked if symptoms suggestive of blood disorders develop, such as unexplained bruising, bleeding, sore throat, or fever.

Use in Children

Colazid is not recommended for use in children. The safety and efficacy of balsalazide have not been established in the paediatric population. Alternative aminosalicylate formulations with established paediatric dosing guidelines may be more appropriate. Consult a paediatric gastroenterologist for advice on treating ulcerative colitis in children.

Pregnancy and Breastfeeding

You should not take Colazid during pregnancy or while breastfeeding. If you are pregnant, think you may be pregnant, are planning to become pregnant, or are breastfeeding, consult your doctor before using this medicine. Your doctor may recommend alternative treatments with a more established safety profile during pregnancy, such as other mesalazine preparations that have more extensive safety data in pregnant women.

If you are a woman of childbearing potential, discuss contraception options with your doctor before starting treatment. If you become pregnant while taking Colazid, contact your doctor immediately – do not stop taking the medicine without medical advice, as uncontrolled ulcerative colitis during pregnancy also carries risks.

Driving and Using Machines

There is no evidence that Colazid affects the ability to drive or operate machinery. However, you are ultimately responsible for assessing your own fitness to drive or perform tasks requiring alertness. If you experience side effects such as dizziness or headache that could impair your judgement, refrain from driving until the symptoms resolve. Consult your doctor if you are unsure.

How Does Colazid Interact with Other Drugs?

Colazid can interact with several important medications including digoxin, methotrexate, azathioprine, and 6-mercaptopurine. These interactions can increase the risk of side effects or alter drug effectiveness. Always inform your doctor about all medicines you are taking, including over-the-counter products and supplements.

Drug interactions with balsalazide and its active metabolite mesalazine are clinically significant and should be carefully considered. The interactions primarily involve medications that are commonly used in patients with inflammatory bowel disease (IBD) or co-existing conditions. Understanding these interactions is essential for safe prescribing and patient safety.

Major Interactions

Other Considerations

In addition to the major interactions listed above, patients should be aware of the following pharmacological considerations when taking Colazid:

• Non-steroidal anti-inflammatory drugs (NSAIDs): Concurrent use of NSAIDs such as ibuprofen or diclofenac should be approached with caution, as both NSAIDs and aminosalicylates may affect renal function. There is also a theoretical risk that NSAIDs may exacerbate ulcerative colitis.
• Warfarin and anticoagulants: Although not a formally recognised interaction, the theoretical salicylate component warrants awareness. Monitor INR if used together.
• Folic acid supplementation: Mesalazine may reduce folate absorption to a minor degree. Patients, especially those also taking methotrexate, should ensure adequate folate intake.
• Vaccines: The immunosuppressive effects of aminosalicylates are minimal; however, if you are also taking immunosuppressive drugs like azathioprine, discuss live vaccine administration with your doctor.

Always tell your doctor, pharmacist, or other healthcare professional about all the medicines you are taking, have recently taken, or might take. This includes prescription medicines, over-the-counter products, herbal remedies, and dietary supplements. Bringing a complete list of your medications to every appointment helps ensure your treatment is safe.

What Is the Correct Dosage of Colazid?

For active ulcerative colitis, the recommended dose is 3 capsules (2.25 g balsalazide) three times daily with or after meals, for up to 12 weeks. For maintenance therapy, the starting dose is 2 capsules (1.5 g) twice daily. Capsules should be swallowed whole with water. Always follow your doctor's instructions.

Adults and Elderly Patients

Children

Colazid is not recommended for use in children. There is insufficient evidence on the safety and efficacy of balsalazide in the paediatric population. Alternative treatments with established paediatric dosing are available, and a paediatric gastroenterologist should guide therapy choices for children with ulcerative colitis.

Elderly Patients

The same dosage recommendations apply to elderly patients as for younger adults. However, elderly patients are more likely to have reduced renal or hepatic function, so closer monitoring may be warranted. Your doctor will assess your kidney and liver function before starting treatment and may adjust the dose if necessary.

Staying Hydrated

It is important to drink sufficient fluids while taking Colazid to maintain adequate hydration. This is especially crucial during episodes of severe or prolonged vomiting and/or diarrhea, high fever, or heavy sweating. Adequate hydration helps protect kidney function, which is particularly relevant since aminosalicylates can occasionally affect the kidneys. Aim for at least 6-8 glasses of water per day, and more if you are experiencing active symptoms.

Missed Dose

If you forget to take a dose at the right time, take it as soon as possible after your next meal. If you miss an entire dose, do not take a double dose to make up for it. Simply take the next dose at your regular time. Consistent dosing is important for maintaining therapeutic drug levels in the colon, so try to establish a routine to help you remember your doses.

Overdose

If you have taken more Colazid than prescribed, or if a child has accidentally ingested the medicine, contact a doctor, hospital emergency department, or poison control centre immediately for an assessment of risk and advice. Take any remaining capsules and the packaging with you. Symptoms of overdose with aminosalicylates may include nausea, vomiting, abdominal pain, and potentially renal impairment. Early medical intervention helps ensure the best outcome.

What Are the Side Effects of Colazid?

Like all medicines, Colazid can cause side effects, although not everyone gets them. The most commonly reported side effects include diarrhea, abdominal pain, nausea, vomiting, and headache. Rare but serious side effects include blood disorders, myocarditis, hepatitis, pancreatitis, and kidney problems. Seek immediate medical attention for signs of severe allergic reactions or blood disorders.

The side effect profile of balsalazide is broadly similar to other aminosalicylates. Most side effects are mild to moderate and often resolve on their own or with dose adjustment. However, some side effects are serious and require immediate medical attention. Understanding the frequency and nature of potential side effects helps patients make informed decisions and recognise warning signs early.

Reporting Side Effects

If you experience any side effects, including those not listed above, report them to your doctor or pharmacist. You can also report suspected side effects directly to your national medicines regulatory authority. Reporting side effects helps to gather more information about the safety of this medicine and allows ongoing monitoring of its benefit-risk balance. In the United Kingdom, reports can be made via the Yellow Card Scheme; in other countries, consult your local reporting system.

How Should You Store Colazid?

Store Colazid at room temperature with no special storage conditions required. Keep the medicine out of the sight and reach of children. Do not use after the expiry date printed on the packaging. Do not dispose of medicines via wastewater or household waste – return unused medicines to your pharmacy.

Colazid does not require any special storage conditions. Store the capsules in their original container with the child-resistant cap securely fastened. Keep the medicine at room temperature, away from excessive heat and moisture. The bathroom medicine cabinet is generally not recommended for storage due to the humidity from showering and bathing.

Always check the expiry date printed on the carton (labelled "EXP"). The expiry date refers to the last day of the stated month. Do not take Colazid after this date, as the medicine may no longer be effective or safe. Colazid is supplied in bottles containing 130 capsules with child-resistant screw caps.

When you have finished your treatment, or if you have capsules that have expired, do not throw them in the bin or flush them down the toilet. Return unused or expired medicines to your local pharmacy for safe disposal. This protects the environment and prevents accidental ingestion by children or animals.

What Does Colazid Contain?

Each Colazid capsule contains 750 mg of balsalazide (as balsalazide disodium) as the active ingredient. The capsule also contains several inactive ingredients (excipients) including magnesium stearate, colloidal anhydrous silica, gelatin, shellac, titanium dioxide (E171), and red, yellow, and black iron oxide (E172).

Active Ingredient

The active substance is balsalazide, present as balsalazide disodium (the disodium salt form). Each hard capsule contains exactly 750 mg of balsalazide (as balsalazide disodium). Balsalazide is a prodrug – it is not pharmacologically active itself but is converted by colonic bacteria into the active anti-inflammatory compound mesalazine (5-aminosalicylic acid).

Inactive Ingredients (Excipients)

The other ingredients in Colazid capsules are:

• Magnesium stearate – a lubricant that prevents the capsule contents from sticking during manufacture
• Colloidal anhydrous silica – a flow agent that ensures uniform filling of capsules
• Gelatin – the capsule shell material
• Shellac – used in the capsule printing ink
• Titanium dioxide (E171) – a white colorant used in the capsule shell
• Red, yellow, and black iron oxide (E172) – colorants that give the capsule its characteristic beige colour

Appearance and Packaging

Colazid capsules are hard, beige-coloured gelatin capsules. They are supplied in bottles with child-resistant screw caps, each bottle containing 130 capsules. The capsules are printed with identification markings for easy identification.

Brand Names by Country

Balsalazide disodium is marketed under different brand names in various countries within the European Economic Area:

• United Kingdom: Colazide 750 mg Capsules
• Sweden: Colazid 750 mg capsules
• Denmark: Premid 750 mg capsules

The marketing authorisation holder is Almirall, S.A., based in Barcelona, Spain. The capsules are manufactured by Catalent Germany Schorndorf GmbH in Germany.

How Does Colazid Work in the Body?

Colazid (balsalazide) is a prodrug that passes through the upper gastrointestinal tract intact. In the colon, bacterial enzymes cleave the molecule to release mesalazine (5-ASA), which acts locally to reduce inflammation in the colonic mucosa by inhibiting prostaglandin and leukotriene synthesis and scavenging damaging free radicals.

Understanding how Colazid works helps explain both its therapeutic benefits and its favourable side effect profile compared to some systemic treatments for ulcerative colitis. The pharmacology of balsalazide can be broken down into three key stages: delivery, activation, and local anti-inflammatory action.

Targeted Drug Delivery

Balsalazide consists of the active drug mesalazine linked via an azo bond to an inert carrier molecule called 4-aminobenzoyl-beta-alanine. This molecular design serves a critical purpose: the azo bond is resistant to the acidic environment of the stomach and the enzymes of the small intestine. As a result, the drug passes through the upper gastrointestinal tract essentially intact, with very little systemic absorption. Studies have shown that only about 1% of orally administered balsalazide is absorbed, making it a truly colon-targeted therapy.

Activation in the Colon

When balsalazide reaches the colon, it encounters the rich bacterial flora that naturally inhabits the large intestine. These bacteria produce enzymes called azoreductases, which cleave the azo bond and release two molecules: the active drug mesalazine (5-aminosalicylic acid) and the inert carrier 4-aminobenzoyl-beta-alanine. The carrier molecule is pharmacologically inactive and is primarily excreted in the faeces. Each 750 mg capsule of balsalazide delivers approximately 262 mg of mesalazine to the colon.

Anti-inflammatory Action

Once released, mesalazine acts locally on the colonic mucosa through several complementary mechanisms:

• Cyclooxygenase (COX) inhibition: Reduces the production of pro-inflammatory prostaglandins (particularly PGE2) in the colonic tissue
• Lipoxygenase inhibition: Decreases the synthesis of leukotrienes, particularly leukotriene B4, a potent chemotactic agent that attracts neutrophils to sites of inflammation
• Free radical scavenging: Mesalazine acts as an antioxidant, neutralising reactive oxygen species (ROS) that are produced in excess by inflammatory cells and contribute to tissue damage
• NF-kB pathway modulation: Mesalazine may inhibit the nuclear factor kappa-B signalling pathway, which controls the expression of genes involved in the inflammatory response
• PPAR-gamma activation: Some evidence suggests that mesalazine activates peroxisome proliferator-activated receptor gamma (PPAR-gamma), which has anti-inflammatory effects in the colonic epithelium

The combination of these mechanisms results in a reduction of mucosal inflammation, healing of ulcers, and relief of symptoms such as bloody diarrhea, abdominal pain, and urgency. With sustained use, mesalazine helps maintain the colonic mucosa in a state of remission, preventing future flares of ulcerative colitis.

Frequently Asked Questions About Colazid