Bismuth subsalicylate belongs to a class of medications called antacids and antidiarrheals. It is used to help relieve heartburn, indigestion, upset stomach, nausea, and diarrhea. How bismuth subsalicylate works is not completely understood, but it is thought to work by coating the stomach and intestines (protecting them from stomach acid), by reducing inflammation in the stomach, and by killing certain bacteria.

Bismuth subsalicylate has also been used to treat and prevent travelers' diarrhea and, along with antibiotics, to treat ulcers believed to be caused by the bacteria H. pylori. In both cases, other treatments are generally more effective.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. As well, some forms of this medication may not be used for all of the conditions discussed here. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor or pharmacist has not recommended it.

Caplets: The usual recommended dose for adults is 525 mg (2 caplets) every 30 minutes as needed, up to a maximum of 16 caplets in 24 hours. For children 10 to 12 years of age, the usual dose is 262 mg (1 caplet) every 30 minutes as needed, up to a maximum of 8 caplets in 24 hours. Children 2 to 9 years of age should use the liquid form of this medication.

Liquid: The usual dose of regular strength liquid for adults is 2 tablespoons (30 mL). For children 10 to 12 years of age, the usual dose is 1 tablespoon (15 mL). For children 5 to 9 years of age, the usual dose is 1½ teaspoons (7.5 mL). For children 2 to 4 years of age, the recommended dose is 1 teaspoon (5 mL). The recommended dose can be given every 30 minutes to a maximum of 8 doses in 24 hours for the regular-strength liquid, and 4 doses in 24 hours for the extra-strength liquid.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

Shake the liquid well before use. To measure the dose correctly, use a medication measuring cup or oral syringe. Household teaspoons and tablespoons do not provide accurate dosing.

It is important to take this medication exactly as recommended by your doctor or pharmacist. This medication is often taken on an "as needed" schedule, however your doctor or pharmacist may recommend that you take it regularly. If you miss a dose, take it as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature, protect it from light and moisture, and keep it out of the reach of children.

Do not use this medication if you:

• are allergic to bismuth subsalicylate or any ingredients of the medication
• are allergic to other salicylate products (e.g., ASA)
• have a bleeding problem
• have a stomach or intestinal ulcer
• have bloody or black stools
• have bleeding in the digestive system
• have decreased kidney function
• are in the second half of pregnancy

Do not give this medication to children or adolescents with flu-like symptoms or chickenpox.

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• constipation
• dark tongue
• grey or dark stools
• headache

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• anxiety
• muscle spasms
• muscle weakness
• severe constipation

Stop taking the medication and seek immediate medical attention if any of the following occur:

• symptoms of a severe allergic reaction (hives, swelling of the mouth or throat, difficulty breathing)
• symptoms of taking too much of this medication (seizures, extreme drowsiness, fast breathing, ringing in the ears, confusion, hearing loss)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Bleeding problems: Bismuth subsalicylate should not be used without a doctor's recommendation if you have ulcers, bleeding disorders, or bloody or black stools.

Diabetes: Salicylate medications can cause decreased blood glucose control. If you have diabetes, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Diarrhea: If you have mucus in your diarrhea or if you also have a fever, contact your doctor before using this medication. Diarrhea can cause dehydration, so ensure you are drinking enough fluids (e.g., oral rehydration solution). If you experience symptoms of dehydration (e.g., dry mouth, excessive thirst, decreased urine production, dizziness, lightheadedness), contact your doctor.

If you have diarrhea that lasts more than 2 days or your symptoms get worse, contact your doctor.

Gout: Salicylate medications can make symptoms of gout worse or cause an attack of gout. If you have gout, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Kidney function: If you have reduced kidney function or kidney disease, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Liver function: Bismuth subsalicylate can build up in the body when the liver is not working properly. If you have reduced liver function or liver disease, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Reye's syndrome: Children and adolescents who have or are recovering from chickenpox or other flu-like symptoms should not use this medication as it may cause Reye's syndrome, a rare but serious condition. If you notice behavior changes along with nausea and vomiting in your child after treating with bismuth subsalicylate, contact your doctor immediately.

Pregnancy: This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: It is not known if bismuth subsalicylate passes into breast milk. If you are breast-feeding and are taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using this medication have not been established for children less than 2 years of age.

Seniors: Seniors may be more at risk of side effects from this medication.

There may be an interaction between bismuth subsalicylate and any of the following:

• acetazolamide
• acetylsalicylic acid (ASA)
• angiotensin converting enzyme inhibitors (ACEIs; captopril, ramipril)
• anticoagulants (e.g., apixaban, dabigatran, edoxaban, fondaparinux, heparin, enoxaparin, rivaroxaban, tinzaparin, warfarin)
• bromocriptine
• celecoxib
• chloroquine
• clopidogrel
• corticosteroids (e.g., dexamethasone, hydrocortisone, prednisone)
• diabetes medications (e.g., acarbose, canagliflozin, glyburide, insulin, linagliptin, lixisenatide, metformin)
• dipyridamole
• furosemide
• influenza virus vaccine
• methotrexate
• non-steroidal anti-inflammatory medications (NSAIDs; e.g., diclofenac, ibuprofen, ketorolac, naproxen)
• potassium phosphate
• prasugrel
• selective serotonin reuptake inhibitors (SSRIs; e.g., citalopram, fluoxetine, paroxetine, sertraline)
• serotonin-norepinephrine reuptake inhibitors (SNRIs; desvenlafaxine, duloxetine, venlafaxine)
• somatostatin analogues (e.g., lanreotide, octreotide, pasireotide)
• sulfamethoxazole
• tetracycline antibiotics (e.g., doxycycline, minocycline, tetracycline)
• ticagrelor
• topiramate
• valproate medications (e.g., divalproex, valproic acid)
• varicella virus-containing vaccines

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.