Anthropometric Measurements as Predictors of Low Birth Weight Among Tanzanian Neonates: A Hospital-Based Study
November 7, 2025
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Brand Name :
Helidac
Synonyms :
metronidazole/tetracycline/bismuth subsalicylate
Class :
H.pylori agents
Brand Name :
Helidac
Synonyms :
metronidazole/tetracycline/bismuth subsalicylate
Class :
H.pylori agents
Dosage Forms & StrengthsÂ
Copackaged blister cardÂ
Chewable tabletsÂ
262.4mg- bismuth subsalicylateÂ
TabletsÂ
250mg- metronidazoleÂ
CapsulesÂ
500mg- tetracyclineÂ
Bismuth subsalicylate- 525mg(two chewable tablets of 262.4mg), metronidazole- 250mg, tetracycline- 500mg orally every 6 hours along with meals for two weeks
Note: histamine(H2) antagonist should be taken along with the therapy
Indication: used in the treatment of infection due to Helicobacter pylori in patients with a history of duodenal ulcers in combination with a histamine(H2) antagonist
Dose Adjustments
Renal dose adjustments
Contraindicated in patients with kidney failure
Hepatic dose adjustments
To be used with caution in patients with liver failure
Dosage Forms & StrengthsÂ
Copackaged blister cardÂ
Chewable tabletsÂ
262.4mg- bismuth subsalicylateÂ
TabletsÂ
250mg- metronidazoleÂ
CapsulesÂ
500mg- tetracyclineÂ
Helicobacter Pylori InfectionÂ
Helicobacter pylori infection
In children of 8 years and above:
Bismuth subsalicylate- 525mg(two chewable tablets of 262.4mg), metronidazole- 250mg, tetracycline- 500mg orally every 6 hours along with meals for two weeks
Note: histamine(H2) antagonist should be taken along with the therapy
Note: Contraindicated for use in the pediatric population
Refer to adult dosingÂ
acitretin, when combined with tetracyclines, can cause an increase in intracranial pressure
levels of bismuth subsalicylate can be increased due to dichlorphenamide
by inhibiting gastrointestinal absorption, the levels of tetracycline can be reduced by aluminum hydroxide
by way of pharmacodynamic antagonism, the activity of amoxicillin can be reduced by tetracycline
the activity of avapritinib can be increased both by metronidazole and tetracycline by altering the intestinal/hepatic CYP3A4 metabolism
by way of pharmacodynamic antagonism, the activity of BCG vaccine live can be reduced by tetracycline
the levels of either of the drugs, i.e., calcium chloride or tetracycline, can be decreased due to the inhibition of gastrointestinal absorption
by altering the intestinal/hepatic CYP3A4 metabolism, the effects of cobimetinib will be increased by metronidazole
by altering the intestinal/hepatic CYP3A4 metabolism, the effects of dihydroergotamine will be increased by metronidazole
the levels of doxycycline can be reduced by bismuth subsalicylate by inhibiting gastrointestinal absorption
by altering the intestinal/hepatic CYP3A4 metabolism, the effects of enzalutamide will be decreased by tetracycline
by altering the intestinal/hepatic CYP3A4 metabolism, the effects of fentanyl will be increased by tetracycline and metronidazole
the levels of oxacillin can be reduced by tetracyclines by way of pharmacodynamic antagonism
by altering the intestinal/hepatic CYP3A4 metabolism, the effects of pemigatinib will be increased by tetracycline and metronidazole
by the mechanism of anticoagulation, by activity of warfarin may be increased by bismuth subsalicylate
by altering CYP2E1 metabolism, the levels of isoniazid may be increased with metronidazole
by altering CYP2C9/10 metabolism, the levels of losartan may be increased with metronidazole
by reducing elimination, the levels of methotrexate may be increased with tetracycline
by altering CYP2C9/10 metabolism, the levels of phenytoin may be increased with metronidazole
by altering the intestinal/hepatic CYP3A4 metabolism, the effects of rifampin will be decreased by tetracycline
Actions and spectrum:Â
Tetracycline and metronidazole cause DNA damage to prevent the synthesis of nucleic acids. Â
Bismuth Subsalicylate: salicylate’s antisecretory effect and Bismuth’s antimicrobial action Â
Tetracycline: inhibits the synthesis of protein by binding to the 30S and possibly the 50S ribosomal subunits of bacteria that are susceptible.Â
Frequency definedÂ
Nausea (12%)Â
Infection of the upper respiratory tract (2.3%)Â
Pain in the abdomen (6.8%)Â
Melena (3%)Â
Diarrhea (6.8%)Â
Dyspepsia (1.5%)Â
Duodenal ulcer (1.5%)Â
Sinusitis (1.1%)Â
Flatulence (1.1%)Â
Anorexia (1.5%)Â
Insomnia (1.1%)Â
Discomfort in the anus (1.1%)Â
Frequency not definedÂ
PruritisÂ
RashÂ
Pain in the chestÂ
ConjunctivitisÂ
Urinary tract infectionÂ
HypertensionÂ
PolyuriaÂ
Joint painsÂ
Urticaria
Black Box Warning Â
Metronidazole has shown carcinogenicity in rats and miceÂ
The carcinogenicity of metronidazole in humans is not knownÂ
Contraindication/Caution:Â
Contraindication:Â
Renal impairmentÂ
Hepatic impairmentÂ
Injury of headÂ
SeizuresÂ
Brain tumorÂ
Pregnancy consideration:Â Â
USFDA pregnancy category: Not recommendedÂ
Lactation:Â Â
It is not recommended as the drugs are known to be excreted in breast milkÂ
Pregnancy category:Â Â
Category A: Studies that were well-controlled and met expectations revealed no risk to the fetus in either the first or second trimester.Â
Category B: There was a lack of studies on pregnant women and no evidence of risk to the fetus in animal experiments.  Â
Category C: there was evidence of risk of adverse effects in animal reproduction studies, and no adequate evidence in human studies must take care of potential risks in pregnant women.   Â
Category D: adequate data with sufficient evidence of human fetal risk from various platforms, but despite the potential risk, and used only in emergency cases for potential benefits.  Â
Category X: Drugs listed in this category outweigh the risks over benefits. Hence, these categories of drugs need to be avoided by pregnant women.   Â
Category N: There is no data available for the drug under this category
Pharmacology:Â
Pharmacodynamics:Â
Pharmacokinetics:Â
AbsorptionÂ
Metronidazole: 80% from the gastrointestinal tractÂ
Tetracycline: 75%Â
DistributionÂ
Bismuth subsalicylate: 90% of bismuth and morethan 90% of salicylate is protein boundÂ
Metronidazole: less than 20% of metronidazole is protein-boundÂ
Tetracycline: 65% of tetracycline is protein boundÂ
MetabolismÂ
Bismuth subsalicylate: it undergoes hydrolysis in the stomach to form salicylic acid and bismuth oxychloride (slightly soluble)Â
Metronidazole: 30%-60% of metabolism undergoes hepatic metabolismÂ
Elimination and excretionÂ
Bismuth subsalicylate: Bismuth is eliminated through urine and feces, whereas salicylate is excreted through urineÂ
Metronidazole: 77% of the drug is eliminated through urine and 14% through fecesÂ
Tetracycline: active form of the drug is eliminated through feces, whereas 60% of the unchanged drug is eliminated through urine Â
Half-life:Â
Bismuth subsalicylate: highly variable Â
Metronidazole:Â Â
Neonates: 25-75hoursÂ
Others: 6-8hoursÂ
Renal disease(end-stage): 21hours Â
Tetracycline: 8-11 hoursÂ
Renal disease(end-stage): 57-108hourÂ
Â
Administration:Â
Tablets and capsules should be taken with mealsÂ
Bismuth subsalicylate: Chew the tablets and swallowÂ
Metronidazole: swallow the tablet with plenty of waterÂ
Tetracycline: swallow the capsule with plenty of waterÂ
Patient information leafletÂ
Generic Name: metronidazole/tetracycline/bismuth subsalicylate Â
Why do we use metronidazole/tetracycline/bismuth subsalicylate?Â
A combination of metronidazole/tetracycline/bismuth subsalicylate is used in the treatment of duodenal ulcer infections due to Helicobacter pylori.
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