Quadruple therapy for H. pylori (with PPI) Pregnancy: Contraindicated in women who are pregnant. Fetal toxicity: advise pregnant women of the risk throughout pregnancy of retardation of skeletal development seen in animal studies, and of permanent discoloration of teeth with tetracycline if used during the second or third trimester. Maternal toxicity: risk of hepatotoxicity with high doses of intravenous tetracycline, also resulting in stillbirth or premature birth.

Bismuth subcitrate potassium with metronidazole and tetracycline hydrochloride

Brand names: Pylera

Used in: Acute Appendicitis

This fixed combination of bismuth subcitrate potassium, metronidazole and tetracycline, given with an acid-suppressing agent, is used as quadruple therapy for the eradication of Helicobacter pylori.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: Three capsules four times a day (after the morning meal, after lunch, after the evening meal and at bedtime) for 10 days. Each capsule contains bismuth subcitrate potassium 140 mg, metronidazole 125 mg and tetracycline hydrochloride 125 mg. Give with omeprazole 20 mg twice a day, after the morning and evening meal, for 10 days.

Route: Oral (swallow the capsules whole with a full glass of water, 8 ounces)

Frequency: Four times daily (after meals and at bedtime) for 10 days

Adequate fluid intake, particularly with the bedtime dose, is recommended to reduce the risk of oesophageal irritation and ulceration by tetracycline hydrochloride. If a dose is missed, continue the normal dosing schedule until the medication is gone; do not take double doses. If more than 4 doses are missed, the prescriber should be contacted. Indication in the fetched label is Helicobacter pylori eradication (studied as bismuth/metronidazole/tetracycline plus omeprazole, OBMT). SOURCE CAVEAT: no eMC/UK SPC posology was fetched - the regimen above comes from US labelling; clinician to verify against the UK SPC (UK products and PPI partner may differ). PAEDIATRIC: no paediatric dosing is stated in the fetched label; permanent tooth discoloration and enamel hypoplasia may develop with use during tooth development (last half of pregnancy, infancy and childhood to the age of 8 years) - verify any paediatric use against a children's formulary.

Dose adjustments

Renal

Contraindicated in severe renal impairment; no other renal dose adjustment is stated in the fetched label sections.

Dose auto-extracted from US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Disulfiram usage within the last two weeks
Alcoholic beverage consumption during therapy and for at least three days afterwards
Patients with Cockayne syndrome
Severe renal impairment
Women who are pregnant
Known hypersensitivity to product components

Side effects

Abnormal faeces (most frequently reported, 5% or more)
Diarrhoea (5% or more)
Nausea (5% or more)
Headache (5% or more)
Severe cutaneous adverse reactions with metronidazole - toxic epidermal necrolysis, Stevens-Johnson syndrome, DRESS and acute generalised exanthematous pustulosis; discontinue immediately if these develop
Central and peripheral nervous system effects - encephalopathy, convulsive seizures, aseptic meningitis and peripheral neuropathy (metronidazole), intracranial hypertension (tetracycline) and neurotoxicity (bismuth-containing products); tooth enamel discoloration and hypoplasia with use during tooth development

Interactions

Disulfiram - psychotic reactions can occur; do not take concurrently or within 2 weeks of disulfiram
Alcohol (and other products containing propylene glycol) - disulfiram-like reaction with abdominal cramps, nausea, vomiting, headaches and flushing; avoid during therapy and for at least 3 days afterwards
Oral contraceptives - decreased efficacy possibly resulting in pregnancy; use a different or additional form of contraception
Anticoagulants - potentiation of anticoagulant effect; monitor prothrombin time/INR closely
Lithium - increased lithium serum concentrations; measure serum lithium and creatinine during therapy
Antacids, multivitamins or dairy products - decreased absorption; do not take concomitantly
Busulfan - increased busulfan serum concentrations; avoid concomitant use and monitor for toxicity
CYP inducers and CYP inhibitors - prolonged or accelerated half-life of metronidazole or concomitant medicines; use with caution

Clinical monograph

How it works

It combines the topical mucosal and antibacterial action of bismuth with two antibacterials, metronidazole and tetracycline, to eradicate Helicobacter pylori, and is co-prescribed with a proton pump inhibitor to raise gastric pH and enhance efficacy.

Prescribing in practice

Patients must be warned to avoid alcohol during metronidazole-containing therapy and for a period afterwards because of the risk of a disulfiram-like reaction.
The tetracycline component contraindicates use in pregnancy, breastfeeding and young children owing to effects on developing teeth and bone, and dairy products and antacids should be separated from dosing as they impair tetracycline absorption.
Completion of the full course is essential to achieve eradication and limit antibacterial resistance.

Monitoring

Routine laboratory monitoring is not required, but confirm eradication after treatment where indicated and review for adverse effects.

Counselling the patient

Take every dose and finish the whole course to clear the infection.
Avoid alcohol during treatment and for a short time afterwards.
Expect the bismuth to darken your stools and tongue, which is harmless.

Evidence & guidelines

Bismuth-based quadruple therapy is recommended in NICE guidance as a Helicobacter pylori eradication regimen, particularly after previous treatment failure.

Reference: NICE NG184; BSG H. pylori; SmPC; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways