A Milestone Moment: FDA Approves Addyi® for Hypoactive Sexual Desire Disorder in Postmenopausal Women
December 17, 2025
Free CME credits
Both our subscription plans include Free CME/CPD AMA PRA Category 1 credits.
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 & Strengths
Copackaged blister card
Chewable tablets
262.4mg- bismuth subsalicylate
Tablets
250mg- metronidazole
Capsules
500mg- tetracycline
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 & Strengths
Copackaged blister card
Chewable tablets
262.4mg- bismuth subsalicylate
Tablets
250mg- metronidazole
Capsules
500mg- tetracycline
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 dosing
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:
Tetracycline and metronidazole cause DNA damage to prevent the synthesis of nucleic acids.
Bismuth Subsalicylate: salicylate’s antisecretory effect and Bismuth’s antimicrobial action
Tetracycline: inhibits the synthesis of protein by binding to the 30S and possibly the 50S ribosomal subunits of bacteria that are susceptible.
Frequency defined
Nausea (12%)
Infection of the upper respiratory tract (2.3%)
Pain in the abdomen (6.8%)
Melena (3%)
Diarrhea (6.8%)
Dyspepsia (1.5%)
Duodenal ulcer (1.5%)
Sinusitis (1.1%)
Flatulence (1.1%)
Anorexia (1.5%)
Insomnia (1.1%)
Discomfort in the anus (1.1%)
Frequency not defined
Pruritis
Rash
Pain in the chest
Conjunctivitis
Urinary tract infection
Hypertension
Polyuria
Joint pains
Urticaria
Black Box Warning
Metronidazole has shown carcinogenicity in rats and mice
The carcinogenicity of metronidazole in humans is not known
Contraindication/Caution:
Contraindication:
Renal impairment
Hepatic impairment
Injury of head
Seizures
Brain tumor
Pregnancy consideration:
USFDA pregnancy category: Not recommended
Lactation:
It is not recommended as the drugs are known to be excreted in breast milk
Pregnancy category:
Category A: Studies that were well-controlled and met expectations revealed no risk to the fetus in either the first or second trimester.
Category B: There was a lack of studies on pregnant women and no evidence of risk to the fetus in animal experiments.
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.
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.
Category X: Drugs listed in this category outweigh the risks over benefits. Hence, these categories of drugs need to be avoided by pregnant women.
Category N: There is no data available for the drug under this category
Pharmacology:
Pharmacodynamics:
Pharmacokinetics:
Absorption
Metronidazole: 80% from the gastrointestinal tract
Tetracycline: 75%
Distribution
Bismuth subsalicylate: 90% of bismuth and morethan 90% of salicylate is protein bound
Metronidazole: less than 20% of metronidazole is protein-bound
Tetracycline: 65% of tetracycline is protein bound
Metabolism
Bismuth subsalicylate: it undergoes hydrolysis in the stomach to form salicylic acid and bismuth oxychloride (slightly soluble)
Metronidazole: 30%-60% of metabolism undergoes hepatic metabolism
Elimination and excretion
Bismuth subsalicylate: Bismuth is eliminated through urine and feces, whereas salicylate is excreted through urine
Metronidazole: 77% of the drug is eliminated through urine and 14% through feces
Tetracycline: active form of the drug is eliminated through feces, whereas 60% of the unchanged drug is eliminated through urine
Half-life:
Bismuth subsalicylate: highly variable
Metronidazole:
Neonates: 25-75hours
Others: 6-8hours
Renal disease(end-stage): 21hours
Tetracycline: 8-11 hours
Renal disease(end-stage): 57-108hour
Administration:
Tablets and capsules should be taken with meals
Bismuth subsalicylate: Chew the tablets and swallow
Metronidazole: swallow the tablet with plenty of water
Tetracycline: swallow the capsule with plenty of water
Patient information leaflet
Generic Name: metronidazole/tetracycline/bismuth subsalicylate
Why do we use metronidazole/tetracycline/bismuth subsalicylate?
A combination of metronidazole/tetracycline/bismuth subsalicylate is used in the treatment of duodenal ulcer infections due to Helicobacter pylori.
Both our subscription plans include Free CME/CPD AMA PRA Category 1 credits.
On course completion, you will receive a full-sized presentation quality digital certificate.
A dynamic medical simulation platform designed to train healthcare professionals and students to effectively run code situations through an immersive hands-on experience in a live, interactive 3D environment.
When you have your licenses, certificates and CMEs in one place, it's easier to track your career growth. You can easily share these with hospitals as well, using your medtigo app.
