PYLERA
Clinical safety rating: caution
Comprehensive clinical and safety monograph for PYLERA (PYLERA).
Bismuth subsalicylate is a salicylate with antimicrobial and anti-inflammatory properties. It inhibits the growth of Helicobacter pylori by binding to the bacterial cell wall, disrupting cell membrane integrity, and inhibiting urease activity. It also reduces gastric inflammation via prostaglandin inhibition.
| Metabolism | The salicylate component is primarily metabolized by conjugation with glycine (forming salicyluric acid) and glucuronic acid. Minor pathways include oxidation to gentisic acid. The bismuth component is largely excreted unchanged in feces. |
| Excretion | Renal: 60-80% as unchanged drug; Fecal: 20-40%; Biliary: minor (<5%) |
| Half-life | Terminal half-life ~6-8 hours; in renal impairment, prolonged up to 20 hours |
| Protein binding | 20-40% bound to serum proteins (albumin) |
| Volume of Distribution | 0.2-0.5 L/kg; indicates distribution into total body water |
| Bioavailability | Oral: 70-80% (fasting); decreased with food (by 30-40%) |
| Onset of Action | Oral: 1-2 hours; intraperitoneal: immediate |
| Duration of Action | 8-12 hours; bacteriostatic effect persists 6-8 hours post-dose |
4 capsules (bismuth subcitrate potassium 420 mg, metronidazole 375 mg, tetracycline 375 mg) orally four times daily (after meals and at bedtime) for 10 days.
| Dosage form | CAPSULE |
| Renal impairment | Contraindicated in patients with CrCl < 30 mL/min. No dose adjustment specified for CrCl ≥ 30 mL/min; use with caution. |
| Liver impairment | Contraindicated in Child-Pugh C cirrhosis. For Child-Pugh A or B, no specific dose adjustment; use with caution and monitor hepatic function. |
| Pediatric use | Safety and efficacy not established in pediatric patients. Not recommended. |
| Geriatric use | No specific dose adjustment; monitor renal function and consider lower doses due to age-related decline in renal function. Use with caution. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for PYLERA (PYLERA).
| Breastfeeding | Contraindicated during breastfeeding. Tetracycline is excreted into breast milk (M/P ratio ~0.5-1.5) and can cause permanent tooth discoloration and skeletal growth retardation in nursing infants. Metronidazole is excreted (M/P ratio ~1.0); infant serum levels can approach therapeutic levels, and concerns for carcinogenicity exist. Bismuth subcitrate potassium is poorly absorbed, but bismuth levels in milk are unknown. Avoid breastfeeding during therapy and for 3 days after last dose. |
| Teratogenic Risk | PYLERA (bismuth subcitrate potassium, metronidazole, tetracycline) is contraindicated in pregnancy due to tetracycline's fetal toxicity. Tetracycline use during second and third trimesters causes permanent tooth discoloration and enamel hypoplasia, and inhibits fetal skeletal growth. First-trimester exposure is associated with neural tube defects and other malformations. Metronidazole crosses placenta; human data shows no consistent increased risk of birth defects, but animal studies show carcinogenicity. Bismuth subcitrate potassium has limited data, but bismuth salts may cause fetal neurotoxicity. |
■ FDA Black Box Warning
Reye's syndrome: Use caution in children and teenagers with viral infections due to the risk of Reye's syndrome when given salicylates.
| Serious Effects |
["Hypersensitivity to bismuth subsalicylate, aspirin, or other salicylates","Active peptic ulcer with bleeding","Children under 12 years of age with viral infections (varicella, influenza) due to Reye's syndrome risk","Concomitant use of tetracycline antibiotics (bismuth chelates tetracycline, reducing absorption)","Severe renal failure (risk of salicylate accumulation)"]
| Precautions | ["Risk of Reye's syndrome in children with viral illnesses","Potential for salicylate toxicity with excessive doses or in patients with renal impairment","May cause temporary darkening of the tongue and stool (harmless)","Avoid use in patients with aspirin or salicylate hypersensitivity","Use with caution in patients with bleeding disorders (salicylate antiplatelet effect)","Potential neurotoxicity with prolonged high-dose bismuth use (rare)"] |
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| Fetal Monitoring | Monitor maternal CBC, LFTs, renal function due to metronidazole and tetracycline toxicities. Assess for signs of neurotoxicity (metronidazole) and hepatotoxicity. In inadvertent pregnancy exposure, fetal ultrasound for skeletal development and growth parameters. Tetracycline can cause maternal hepatotoxicity (especially in pregnancy) and pancreatitis. |
| Fertility Effects | Limited human data. Tetracycline may reduce fertility in males via impaired spermatogenesis. Metronidazole has been associated with reduced sperm motility and abnormal morphology in animal studies. Bismuth subcitrate potassium has no known reproductive toxicity. Overall, potential for transient fertility impairment during therapy. |