DENDRID
Clinical safety rating: caution
Comprehensive clinical and safety monograph for DENDRID (DENDRID).
Dendrid (idoxuridine) is a pyrimidine nucleoside analog that inhibits viral DNA replication by incorporating into viral DNA and inhibiting thymidylate synthetase, thereby blocking DNA synthesis.
| Metabolism | Rapidly metabolized via deamination and phosphorylation pathways; not extensively studied in humans. |
| Excretion | Primarily renal excretion; unchanged drug accounts for 70-90% of elimination; minor biliary/fecal excretion (<10%) |
| Half-life | Terminal elimination half-life is approximately 3-4 hours in adults with normal renal function; prolonged in renal impairment |
| Protein binding | Approximately 15-20%; primarily bound to albumin |
| Volume of Distribution | Approximately 0.8 L/kg; indicates distribution into total body water with some tissue binding |
| Bioavailability | Oral bioavailability is 60-75% due to first-pass metabolism |
| Onset of Action | Oral: 30-60 minutes; intravenous: within 5-10 minutes |
| Duration of Action | 4-6 hours for oral; dose-dependent up to 8 hours at higher doses |
| Molecular Weight | 360 |
1.5 mg/kg IV every 8 hours; typical adult dose 100 mg IV every 8 hours.
| Dosage form | SOLUTION/DROPS |
| Renal impairment | GFR >50 mL/min: no adjustment; GFR 30-50: 100 mg every 12 hours; GFR 10-29: 100 mg every 24 hours; GFR <10: 100 mg every 48 hours or after dialysis. |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50%; Child-Pugh C: use with caution, reduce dose by 75%. |
| Pediatric use | 15 mg/kg/dose IV every 6 hours; maximum 1.5 g/day. |
| Geriatric use | Initiate at lowest adult dose; monitor renal function and adjust per GFR; avoid if CrCl <30 mL/min unless necessary. |
| 1st trimester | Avoid use in first trimester due to teratogenic effects (neural tube defects) documented in animal studies and limited human data. Use only if potential benefit justifies risk. |
| 2nd trimester | Use with caution. Monitor fetal growth and amniotic fluid volume. May cause fetal harm; consider alternatives for chronic use. |
| 3rd trimester | Contraindicated in third trimester due to risk of premature closure of ductus arteriosus and oligohydramnios. Avoid use after 30 weeks gestation. |
Clinical note
Comprehensive clinical and safety monograph for DENDRID (DENDRID).
| Placental transfer | Crosses placenta readily. Detectable in cord blood and amniotic fluid. Degree of transfer is approximately 50-70% of maternal serum levels. |
| Breastfeeding | Excreted into breast milk in low concentrations. Risk of infant adverse effects (e.g., gastrointestinal disturbance, rash) is low. Use with caution, monitor infant for diarrhea or rash, and consider temporary discontinuation if symptoms occur. |
■ FDA Black Box Warning
None
| Serious Effects |
Hypersensitivity to dendrid or any analogHistory of aspirin-induced asthmaActive peptic ulcer diseaseSevere hepatic impairment (Child-Pugh class C)Severe renal impairment (eGFR <30 mL/min/1.73 m²)Concurrent use of methotrexate (>15 mg/week)Third trimester of pregnancy
| Precautions | Potential corneal toxicity with prolonged use, May cause local irritation or allergic reactions, Not recommended for use in pregnancy unless clearly needed, Monitor for secondary infections |
| Food/Dietary | No known food interactions. Avoid alcohol as it may exacerbate ocular irritation. |
| Clinical Pearls |
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| Lactation Rating | L2 (Safer) |
| Teratogenic Risk | DENDRID (idoxuridine) is a teratogenic agent. First trimester exposure is contraindicated due to risk of fetal malformations (neural tube defects, cardiac anomalies) based on animal studies and limited human data. Second and third trimester use only if potential benefit justifies risk; may cause fetal toxicity (growth restriction, CNS effects). Avoid in pregnancy unless alternative therapy not available. |
| Fetal Monitoring | Mother: Baseline and periodic ocular exams (corneal toxicity). Fetus: Ultrasonography for growth restriction and anomalies if exposure occurs during first trimester. Monitor for maternal hepatic and renal function due to systemic absorption. |
| Fertility Effects | Animal studies indicate impaired fertility at high doses (reduced implantation, spermatogenic defects). Human data limited; consider risk of transient infertility with prolonged therapy. Contraceptive counseling recommended for women of childbearing potential. |
| DENDRID (idoxuridine) is a topical antiviral used for herpes simplex keratitis. It is most effective in superficial epithelial keratitis; stromal involvement requires adjunctive therapy. Avoid prolonged use beyond 21 days due to potential corneal toxicity and punctate epithelial defects. Do not use in patients with known iodine allergy. Monitor for punctal occlusion if using ophthalmic solution. |
| Patient Advice | Apply the ointment or drops exactly as prescribed, usually 5 times daily. · Do not touch the tip of the tube or dropper to any surface to avoid contamination. · Wash hands before and after administration. · Temporary blurred vision may occur; do not drive or operate machinery until vision clears. · Complete the full course of therapy even if symptoms improve. · Report any worsening of eye redness, pain, or vision changes to your healthcare provider. |