PHOSPHOLINE IODIDE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for PHOSPHOLINE IODIDE (PHOSPHOLINE IODIDE).
Irreversible acetylcholinesterase inhibitor, increasing acetylcholine at muscarinic and nicotinic receptors.
| Metabolism | Primarily hydrolyzed by liver and plasma esterases, with renal excretion of metabolites. |
| Excretion | Renal: primarily unchanged drug and metabolites; fecal: minimal. Exact percentages not established. |
| Half-life | Terminal elimination half-life is approximately 1-2 hours; clinical effect outlasts plasma levels due to irreversible acetylcholinesterase inhibition. |
| Protein binding | Not extensively studied; low binding expected (likely <20%) due to high polarity. |
| Volume of Distribution | Not well characterized; expected to be small (approximately 0.3-0.5 L/kg) due to hydrophilic nature. |
| Bioavailability | Topical ocular: limited systemic absorption; parenteral: 100% by definition. |
| Onset of Action | Ocular (topical): 10-30 minutes for miosis; systemic effects may occur within minutes after parenteral administration. |
| Duration of Action | Ocular miosis and accommodation spasm last 24-48 hours; systemic effects may persist for days due to enzyme regeneration. |
0.125% to 0.25% solution, 1 drop in the affected eye(s) every 12 to 24 hours; maximum 0.25% solution twice daily.
| Dosage form | FOR SOLUTION |
| Renal impairment | No specific dose adjustment recommended; use with caution in renal impairment due to potential systemic absorption. |
| Liver impairment | No specific dose adjustment recommended; use with caution in hepatic impairment. |
| Pediatric use | Not typically indicated; if used, 0.125% solution 1 drop in affected eye(s) every 12 hours, adjusted based on response and adverse effects. |
| Geriatric use | Use lowest effective concentration (0.125%) and monitor for systemic side effects due to potential age-related reduced clearance. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for PHOSPHOLINE IODIDE (PHOSPHOLINE IODIDE).
| Breastfeeding | No human data. M/P ratio unknown. Small molecular weight suggests possible excretion into milk. Potential for infant toxicity due to cholinergic effects. Contraindicated during breastfeeding due to risk of infant muscle weakness, bradycardia, or excessive secretions. |
| Teratogenic Risk | Insufficient human data. In animal studies, echothiophate (PHOSPHOLINE IODIDE) has not been shown to cause fetal harm. However, due to anticholinesterase activity, theoretical risk of fetal bradycardia or muscle weakness if used near term. Avoid in first trimester unless benefit outweighs risk. |
■ FDA Black Box Warning
None
| Serious Effects |
["Hypersensitivity to echothiophate or other organophosphates","Active uveitis","Angle-closure glaucoma (relative)","Pregnancy (avoid use, especially near term)"]
| Precautions | ["Systemic absorption can cause bradycardia, hypotension, bronchospasm, and excessive salivation; use with caution in patients with asthma, bradycardia, or GI obstruction; monitor intraocular pressure and visual fields"] |
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| Fetal Monitoring | Monitor maternal heart rate, blood pressure, and signs of cholinergic toxicity (e.g., excessive salivation, lacrimation, diarrhea, bradycardia). In fetus, monitor fetal heart rate patterns; prolonged use may require ultrasound for fetal growth and amniotic fluid volume as systemic absorption may cause uterine irritability. |
| Fertility Effects | No adequate studies in humans. Animal studies show no impairment of fertility. Theoretical risk due to cholinergic effects on reproductive tract motility, but clinical significance unknown. |