WYAMYCIN E
Clinical safety rating: caution
Comprehensive clinical and safety monograph for WYAMYCIN E (WYAMYCIN E).
Aminoglycoside antibiotic that binds to the 30S ribosomal subunit, causing misreading of mRNA and inhibiting bacterial protein synthesis.
| Metabolism | Primarily excreted unchanged by glomerular filtration; minimal hepatic metabolism. |
| Excretion | Primarily renal (60-80% unchanged) via glomerular filtration; biliary/fecal <5%. |
| Half-life | 2.5 hours (increased to 5-8 hours in neonates and up to 24-48 hours in anuria). |
| Protein binding | Low (<10%), primarily to albumin. |
| Volume of Distribution | 0.2-0.4 L/kg, indicating limited extravascular distribution; higher in neonates. |
| Bioavailability | IM: ~100% (well absorbed); topical: negligible systemic absorption. |
| Onset of Action | IM: 1-2 hours; IV: rapid (end of infusion); topically: variable. |
| Duration of Action | 6-12 hours depending on dose and renal function; prolonged in renal impairment. |
| Molecular Weight | 581.6 Da |
500 mg intramuscularly or intravenously every 12 hours; or 1 gram every 24 hours for severe infections.
| Dosage form | SUSPENSION |
| Renal impairment | For CrCl 30-50 mL/min: administer 250 mg every 12 hours; for CrCl 10-29 mL/min: administer 250 mg every 24 hours; for CrCl <10 mL/min: administer 250 mg every 48 hours. |
| Liver impairment | No specific dose adjustments are recommended for hepatic impairment; use with caution in severe liver disease. |
| Pediatric use | 10 mg/kg intramuscularly or intravenously every 12 hours for neonates and infants; 5-10 mg/kg every 12 hours for children up to 12 years; maximum single dose 500 mg. |
| Geriatric use | Initial dose same as adults; subsequent doses and intervals adjusted based on renal function (CrCl); monitor for ototoxicity and nephrotoxicity. |
| 1st trimester | Avoid; potential for teratogenicity (e.g., neural tube defects) based on animal studies and limited human data. |
| 2nd trimester | Use only if clearly needed; risk of fetal ototoxicity and nephrotoxicity, especially with prolonged or high-dose therapy. |
| 3rd trimester | Avoid; risk of fetal auditory and renal toxicity, including eighth cranial nerve damage. |
Clinical note
Comprehensive clinical and safety monograph for WYAMYCIN E (WYAMYCIN E).
| Placental transfer | Crosses placenta; achieves fetal serum concentrations approximately 50% of maternal levels. |
| Breastfeeding | Excreted into breast milk in small amounts; potential for infant gut flora alteration and allergic reaction. Use with caution, monitor infant for loose stools or candidiasis. |
■ FDA Black Box Warning
Aminoglycosides can cause nephrotoxicity, ototoxicity (vestibular and cochlear), and neuromuscular blockade. Risk is increased with higher doses, prolonged use, or in patients with renal impairment. Ototoxicity may be irreversible. Avoid concurrent use with other ototoxic or nephrotoxic drugs.
| Serious Effects |
Hypersensitivity to aminoglycosides or any componentPreexisting severe renal impairment (CrCl < 20 mL/min) unless dialysis availableHistory of severe ototoxicity from previous aminoglycoside useMyasthenia gravis
| Precautions | Monitor renal function (serum creatinine, BUN) and audiometric tests before and during therapy. Adjust dose based on renal function. Avoid prolonged therapy (>7-10 days) due to increased toxicity risk. Use with caution in patients with neuromuscular disorders (e.g., myasthenia gravis) due to potential neuromuscular blockade. |
| Food/Dietary | Grapefruit juice may increase erythromycin levels and QT prolongation risk. Avoid alcohol as it may worsen gastrointestinal irritation. High-fat meals may delay absorption; take on empty stomach if possible. |
Loading safety data…
| Lactation Rating |
| L3 (Limited data - probably compatible with careful monitoring) |
| Teratogenic Risk | Wyamycin E contains erythromycin, a macrolide antibiotic. Category B: No evidence of risk in humans. Animal studies did not show fetal harm, but adequate human studies in pregnant women are lacking. Use only if clearly needed. Risk in first trimester: unlikely significant. Second/third trimester: generally safe; preferred over azithromycin for certain infections. Avoid estolate salt form due to hepatotoxicity risk. |
| Fetal Monitoring | Monitor maternal liver function tests (LFTs) due to potential hepatotoxicity (especially with estolate). Assess for allergic reactions. No specific fetal monitoring required; routine prenatal care. In neonates exposed via breast milk, monitor for signs of adverse effects. |
| Fertility Effects | No known adverse effects on fertility in humans. Animal studies showed no impairment at therapeutic doses. No significant impact on ovulation, spermatogenesis, or implantation. |
| Clinical Pearls | WYAMYCIN E is a combination product containing erythromycin and an expectorant (likely guaifenesin). Use with caution in patients with hepatic impairment or prolonged QT interval. Monitor for drug interactions with CYP3A4 inhibitors and QT-prolonging agents. Efficacy in acute bronchitis is limited; reserve for pertussis or mycoplasma infections. |
| Patient Advice | Take with a full glass of water to reduce gastrointestinal upset. · Complete the entire course even if symptoms improve to prevent resistance. · Avoid alcohol and grapefruit juice during therapy. · Report severe diarrhea, palpitations, or rash immediately. · May cause nausea, vomiting, or abdominal pain; take with food. |