July 30, 2016
Recommended Topic Related To:


"The U.S. Food and Drug Administration today allowed marketing in the U.S. of the first direct blood test for detection of five yeast pathogens that cause bloodstream infections: Candida albicans and/or Candida tropicalis, Candida parapsilosis, Ca"...



Helidac Side Effects Center

Medical Editor: John P. Cunha, DO, FACOEP

Last reviewed on RxList 9/29/2015

Helidac Therapy (bismuth subsalicylate/metronidazole/tetracycline hydrochloride) is a combination of antibiotics used to treat Helicobacter pylori, a bacterial infection involved in causing stomach ulcers. Common side effects of Helidac Therapy include nausea, vomiting, indigestion, diarrhea, stomach or abdominal pain, constipation, loss of appetite, headache, mouth pain, metallic taste in mouth, trouble swallowing, dizziness, cold symptoms (stuffy nose, sneezing, sore throat), vaginal itching or discharge, swollen tongue, or black or "hairy" tongue.

The recommended adult dosages are: bismuth subsalicylate, 525 mg (two 262.4 mg-chewable tablets), metronidazole, 250 mg (one 250-mg tablet), and tetracycline hydrochloride, 500 mg (one 500-mg capsule) taken four times daily for 14 days plus an H2 antagonist approved for the treatment of acute duodenal ulcer. Helidac may interact with cholestyramine or colestipol, antacids containing aluminum or magnesium, minerals such as iron, zinc, calcium, and magnesium [found in dairy products (milk, cheese, etc.) and over-the-counter vitamin and mineral supplements], anticoagulants, penicillin and cephalosporin antibiotics, birth control pills, disulfiram, cimetidine, lithium, phenytoin or phenobarbital, diabetes medicines, aspirin, probenecid, and sulfinpyrazone. Tell your doctor all medications and supplements you use. Helidac Therapy is not recommended for use during pregnancy because of possible harm to a fetus. Women of child-bearing age should use non-hormonal birth control (e.g., condom, diaphragm with spermicide) while taking this medication. Consult your doctor. This combination product contains drugs that may pass into breast milk and could have undesirable effects on a nursing infant. Breast-feeding is not recommended.

Our Helidac (bismuth subsalicylate/metronidazole/tetracycline hydrochloride) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What is Patient Information in Detail?

Easy-to-read and understand detailed drug information and pill images for the patient or caregiver from Cerner Multum.

Helidac in Detail - Patient Information: Side Effects

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

  • severe diarrhea, or diarrhea that is watery or bloody;
  • confusion, severe headache, ringing in your ears, dizziness;
  • vision problems, pain behind your eyes;
  • nausea, upper stomach pain, itching, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes);
  • seizure (convulsions); or
  • pale skin, feeling light-headed or short of breath, rapid heart rate, trouble concentrating.

Common side effects may include:

  • stomach pain, indigestion, vomiting;
  • constipation, mild diarrhea;
  • cold symptoms such as stuffy nose, sneezing, sore throat;
  • mouth pain, metallic taste in your mouth;
  • vaginal itching or discharge;
  • mild headache; or
  • swollen tongue, black or "hairy" tongue, trouble swallowing.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Read the entire detailed patient monograph for Helidac (Bismuth Subsalicylate)

What is Patient Information Overview?

A concise overview of the drug for the patient or caregiver from First DataBank.

Helidac Overview - Patient Information: Side Effects

SIDE EFFECTS: Nausea, vomiting, diarrhea, abdominal pain, constipation, loss of appetite, headache, metallic taste in mouth, or dizziness may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.

Your tongue may turn dark in color while taking this medication. This is harmless and the effect will disappear when you stop the medication.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor immediately if any of these unlikely but serious side effects occur: ringing in the ears, sore mouth, joint pain, numbness/tingling of arms/legs, frequent/painful urination, discolored teeth, mental/mood changes (e.g., nervousness, irritability, depression).

Tell your doctor immediately if any of these rare but very serious side effects occur: severe headache, stiff/painful neck, difficult/painful swallowing, heartburn, unusual tiredness, change in the amount of urine, dark urine, unusual weakness, yellowing eyes/skin, persistent nausea/vomiting, severe constipation, severe stomach/abdominal pain, signs of infection (e.g., fever, persistent sore throat), easy bruising/bleeding.

Seek immediate medical attention if any of these rare but very serious side effects occur: seizures, chest/jaw/left arm pain, confusion, slurred speech, vision changes.

This product can commonly cause dark stools that are usually not serious. However, you may not be able to tell this effect apart from blood in the stool, which could be a sign of a severe reaction. Therefore, tell your doctor immediately if you develop any dark stools.

Tetracycline may rarely cause a serious increase in pressure inside the skull (intracranial hypertension-IH). The risk of this side effect is greater for women of childbearing age who are overweight or who have had IH in the past. If IH develops, it usually goes away after tetracycline is stopped; however, there is a chance of permanent vision loss or blindness. Get medical help right away if you have: persistent/severe headache, vision changes (such as blurred/double vision, decreased vision, sudden blindness), persistent nausea/vomiting.

This medication may rarely cause a severe intestinal condition (Clostridium difficile-associated diarrhea) due to a type of resistant bacteria. This condition may occur weeks to months after treatment has stopped. Tell your doctor immediately if you develop persistent diarrhea, abdominal or stomach pain/cramping, blood/mucus in your stool. Do not use anti-diarrhea products or narcotic pain medications if you have any of these symptoms because these products may make them worse.

Use of this medication for prolonged or repeated periods may result in oral thrush or a new yeast infection. Contact your doctor if you notice white patches in your mouth, a change in vaginal discharge, or other new symptoms.

A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US -

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Read the entire patient information overview for Helidac (Bismuth Subsalicylate)

What is Prescribing information?

The FDA package insert formatted in easy-to-find categories for health professionals and clinicians.

Helidac FDA Prescribing Information: Side Effects
(Adverse Reactions)


The most common adverse reactions ( ≥ 1%) reported in clinical trials when all three components of this therapy were given concomitantly are listed in Table 1 below. The majority of the adverse reactions were related to the gastrointestinal tract, were reversible, and infrequently led to discontinuation of therapy.

Table 1: Incidence of Adverse Reactions Reported in Clinical Trials ( ≥ 1%)†

Adverse Reactions Bismuth Subsalicylate, Metronidazole, and Tetracycline ‡
(N = 266)
% Patients
Nausea 12
Diarrhea 6.8
Abdominal Pain 6.8
Melena 3
Upper Respiratory Infection 2.3
Constipation 1.9
Anorexia 1.5
Asthenia 1.5
Vomiting 1.5
Discolored Tongue* 1.5
Headache 1.5
Dyspepsia 1.5
Dizziness 1.5
Stool Abnormality** 1.1
Duodenal Ulcer 1.1
Sinusitis 1.1
Taste Perversion*** 1.1
Flatulence 1.1
GI Hemorrhage 1.1
Pain 1.1
Insomnia 1.1
Anal Discomfort 1.1
Paresthesia 1.1
* darkening of the tongue
** black or dark stools
*** metallic taste
† Includes reactions reported at ≥ 1% in patients taking bismuth subsalicylate, metronidazole, and tetracycline in Studies 1, 2, 3, and 4 (see Clinical Studies).
‡ In Studies 1, 2, and 3(N = 197), most patients were on concomitant acid suppression therapy.

The additional adverse reactions ( < 1%) reported in clinical trials when all three components of this therapy were given concomitantly are listed below and divided by body system:

Gastrointestinal: dry mouth, dysphagia, eructation, GI monilia, glossitis, intestinal obstruction, rectal hemorrhage, stomatitis

Skin: acne, ecchymosis, photosensitivity reaction (see WARNINGS), pruritus, rash

Cardiovascular: cerebral ischemia, chest pain, hypertension, myocardial infarction

CNS: nervousness, somnolence

Musculoskeletal: arthritis, rheumatoid arthritis, tendonitis

Metabolic:SGOT increase, SGPT increase

Urogenital: urinary tract infection

Other: conjunctivitis, flu syndrome, infection, malaise, neoplasm, rhinitis, syncope, tooth disorder

Other Important Adverse Reactions from Labeling for the Individual Components of HELIDAC Therapy


Blood and Lymphatic system disorders: reversible neutropenia (leucopenia) in cases of prolonged treatment; rarely reversible thrombocytopenia however no persistent haematological abnormalities attributable to metronidazole have been observed. (See PRECAUTIONS)

Cardiac disorders: Flattening of the T-wave may be seen in electrocardiographic tracings.

Gastrointestinal disorders: Furry tongue, glossitis, stomatitis; these may be associated with a sudden overgrowth of candida which may occur during therapy; epigastric distress (See PRECAUTIONS)

Immune system disorders: Urticaria, erythematous rash, Stevens-Johnson Syndrome, toxic epidermal necrolysis, flushing, nasal congestion, dryness of the mouth (or vagina or vulva) and fever (See CONTRAINDICATIONS)

Metabolism and nutrition disorders: Cases of pancreatitis have been reported, which abated on withdrawal of the drug, have been reported.

Nervous system disorders: The most serious adverse reactions reported in patients treated with metronidazole have been convulsive seizures, encephalopathy, aseptic meningitis, optic and peripheral neuropathy, the latter characterized mainly by numbness or paresthesia of an extremity. In addition, patients have reported syncope, vertigo, incoordination, ataxia, confusion, dysarthria, irritability, depression, weakness, and insomnia. (See WARNINGS)

Renal disorders: Dysuria, cystitis, polyuria, incontinence, and a sense of pelvic pressure. Instances of darkened urine have been reported by approximately one patient in 100,000. Although the pigment which is probably responsible for this phenomenon has not been positively identified, it is almost certainly a metabolite of metronidazole and seems to have no clinical significance.

Other: Proliferation of Candida in the vagina, dyspareunia, decrease of libido, proctitis, and fleeting joint pains sometimes resembling “serum sickness.” Crohn's disease patients are known to have an increased incidence of gastrointestinal and certain extraintestinal cancers. There have been some reports in the medical literature of breast and colon cancer in Crohn's disease patients who have been treated with metronidazole at high doses for extended periods of time. A cause and effect relationship has not been established.

Tetracycline Hydrochloride

Blood and lymphatic system disorders: Hemolytic anemia, thrombocytopenia, thrombocytopenic purpura, neutropenia, and eosinophilia.

Gastrointestinal disorders: Anorexia, nausea, epigastric distress, glossitis, black hairy tongue, dysphagia, enterocolitis, and inflammatory lesions (with monilial overgrowth) in the anogenital region. Rare instances of esophagitis and esophageal ulceration have been reported in patients taking the tetracycline-class antibiotics in capsule and tablet form. Most of the patients who experienced esophageal irritation took the medication immediately before going to bed. Permanent discoloration of teeth may be caused when tetracycline is used during tooth development. Enamel hypoplasia has also been reported. (See WARNINGS)

Hypersensitivity: urticaria, angioneurotic edema, anaphylaxis, anaphylactoid purpura, pericarditis, exacerbation of systemic lupus erythematosus and serum sickness-like reactions, as fever, rash, and arthralgia.

Liver disorders: Hepatotoxicity and liver failure have been observed in patients receiving large doses of tetracycline and in tetracycline-treated patients with renal impairment. Increases in liver enzymes and hepatic toxicity have been reported rarely.

Nervous system disorders: Pseudotumor cerebri (benign intracranial hypertension) in adults and bulging fontanels in infants, Visual disturbances. Tinnitus and myasthenic syndrome have been reported rarely.

Renal and urinary disorders: Rise in BUN has been reported and is possibly dose related (See CONTRAINDICATIONS)

Skin and subcutaneous tissue disorders: Maculopapular and erythematous rashes have been reported. Stevens-Johnson syndrome, toxic epidermal necrolysis, and erythema multiforme have been reported. Onycholysis, discoloration of the nails, exfoliative dermatitis, and photosensitivity have been rarely reported. (See PRECAUTIONS)

Other: When given over prolonged periods, tetracyclines have been reported to produce brown-black microscopic discoloration of thyroid glands. No abnormalities of thyroid function studies are known to occur.

Read the entire FDA prescribing information for Helidac (Bismuth Subsalicylate)

Helidac - User Reviews

Helidac User Reviews

Now you can gain knowledge and insight about a drug treatment with Patient Discussions.

Here is a collection of user reviews for the medication Helidac sorted by most helpful. Patient Discussions FAQs

Report Problems to the Food and Drug Administration


You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

Women's Health

Find out what women really need.