Metronidazole/tetracycline/bismuth subsalicylate

Contraindications

Metronidazole

• Hypersensitivity to metronidazole or other nitroimidazoles (although cautious desensitization has been applied)
• Pregnancy 1st trimester (controversial)
• Avoid during breastfeeding (see lactation)

Bismuth Subsalicylate

• Hypersensitivity to bismuth, aspirin, other salicylates
• Infectious diarrhea, high fever, von Willebrand's disease, hemorrhage, GI bleeding, hemophilia
• Chicken pox or influenza in Peds (risk of Reye's synd)

Tetracycline

• Hypersensitivity to drug or formulation components

Pylera

• Coadministration with methoxyflurane, severe renal impairment; disulfiram (within the past 2 weeks), or ethanol or other products containing propylene glycol (during and for at least 3 days following therapy with Pylera)

Cautions

Skin and subcutaneous disorders including Stevens-Johnson syndrome, toxic epidermal necrolysis and DRESS syndrome (drug rash with eosinophilia and systemic symptoms) reported; discontinue treatment at first evidence of cutaneous reaction

Metronidazole has been shown to be carcinogenic in mice and rats; it is unknown whether metronidazole is associated with carcinogenicity in humans

Metronidazole

• Caution in CNS disease, history of blood dyscrasias
• Avoid alcohol
• May result in candidiasis
• Intravaginal: avoid vaginal intercourse or use of vaginal douches during course of treatment
• Antiandrogen: May cause gynecomastia
• Patients with hepatic impairment metabolize metronidazole slowly, with resultant accumulation of metronidazole in plasma; use with caution in patients with mild to moderate hepatic impairment; therapy may not be appropriate for patients with severe hepatic impairment (Child-Pugh C)

Tetracycline

• IV/IM no longer commercially available
• Psudomoter crebri reported (resolves with discontinuation)
• Prolonged use may cause superinfection
• May cause photosensitivity

Bismuth Subsalicylate

• May cause black tongue &/or black stool
• May interfere with GI radiographic tests

Central and Peripheral Nervous System Effects

• Metronidazole: Convulsive seizures, encephalopathy, aseptic meningitis and peripheral neuropathy (including optic neuropathy) have been reported
• Tetracycline: Intracranial hypertension (IH), including pseudotumor cerebri, associated with use of tetracyclines; women of childbearing age who are overweight or have a history of IH are at greater risk for developing tetracycline associated IH; avoid concomitant use of isotretinoin because isotretinoin is also known to cause IH; although IH typically resolves after discontinuation of treatment, possibility for permanent visual loss exists; if visual disturbance occurs during treatment, prompt ophthalmologic evaluation is warranted; since intracranial pressure can remain elevated for weeks after drug cessation, patients should be monitored until they stabilize