Echothiophate
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Drug Name: Echothiophate
Therapeutic Class: Cholinergic (Parasympathomimetic) Agent
Subclass: Irreversible Acetylcholinesterase Inhibitor (Organophosphate)
Schedule: Schedule H
Route(s): Ophthalmic (topical)
Formulations:
| Formulation | Strength |
|---|---|
| Ophthalmic solution | 0.03% |
Note: Limited availability in India; often requires named-patient import or hospital-based compounding
ADULT INDICATIONS + DOSING
Primary Indications (Approved / Standard in India)
⮚ Chronic Open-Angle Glaucoma (Refractory Cases)
| Parameter | Recommendation |
|---|---|
|
Starting dose
|
0.03% solution — one drop once daily in affected eye(s) |
|
Titration
|
Based on IOP response; increase to twice daily if needed after 2–4 weeks |
|
Usual maintenance dose
|
0.03% once daily |
|
Maximum dose
|
0.03% twice daily |
Clinical Notes:
- Onset of significant IOP reduction: 1–4 weeks
- Miotic effect may persist days to weeks after discontinuation
- Reserve for patients unresponsive to first-line agents (beta-blockers, prostaglandin analogues)
- Discontinue immediately if signs of cataract progression or systemic organophosphate toxicity
⮚ Accommodative Esotropia (Specialist Use Only)
| Parameter | Recommendation |
|---|---|
|
Starting dose
|
0.03% solution — one drop once daily |
|
Titration
|
Adjust based on ocular alignment and accommodation reduction under specialist guidance |
|
Usual maintenance dose
|
0.03% once daily |
|
Maximum dose
|
0.03% twice daily |
Clinical Notes:
- Used when surgical correction not feasible or as post-surgical adjunct
- Short-term use recommended; consider periodic drug-free intervals
- Requires paediatric ophthalmologist supervision
Secondary Indications – Adults (Off-label)
None documented or supported in Indian clinical practice.
PAEDIATRIC DOSING (Specialist Only)
Primary Indication: Accommodative Esotropia
| Age Group | Dosing | Notes |
|---|---|---|
|
≥2 years
|
0.03% — one drop once daily, may increase to twice daily based on response | Under paediatric ophthalmology supervision only |
|
<2 years
|
NOT RECOMMENDED
|
High risk of systemic absorption and toxicity |
Dosing Protocol:
- Starting dose: 0.03% once daily in the affected eye
- Titration: Increase to twice daily only if inadequate response after 2–4 weeks
- Maximum dose: 0.03% twice daily
- Duration: Short-term use preferred; periodic drug-free intervals advised
Safety Monitoring (Mandatory):
- Pupillary size and ocular alignment at each visit
- Signs of systemic cholinergic toxicity: excessive salivation, diarrhoea, bradycardia, bronchospasm
- Growth and developmental milestones in prolonged use
⚠️ Minimum Age: Not recommended below 2 years except in exceptional circumstances under specialist supervision
Secondary Indications – Paediatric (Off-label)
None documented in Indian practice.
Renal Adjustments
Not applicable — Topical ophthalmic administration with minimal systemic absorption; no renal dose adjustment required.
Hepatic Adjustment
| Impairment Severity | Recommendation |
|---|---|
|
Mild
|
Not applicable — minimal systemic absorption |
|
Moderate
|
Not applicable — minimal systemic absorption |
|
Severe
|
Not applicable — minimal systemic absorption |
Standard ophthalmic dosing may be used. Monitor for systemic cholinergic effects if any concern regarding hepatic metabolism of absorbed drug.
Contraindications
- Known hypersensitivity to echothiophate iodide or other organophosphate compounds
- Active uveitis or iritis
- Narrow-angle glaucoma or anatomically narrow anterior chamber angle
- History of or active retinal detachment
- Use within 6 weeks prior to general anaesthesia involving succinylcholine or other depolarising neuromuscular blockers
- Aphakia with intact posterior capsule (high risk of cystoid macular oedema)
Cautions
- Long-term use associated with anterior and posterior subcapsular cataract formation — periodic lens examination required
- Increased risk of retinal detachment in myopic patients or those with peripheral retinal pathology
- Potential for systemic parasympathomimetic effects, especially in children or with excessive dosing/nasolacrimal absorption
- Use with caution in patients with:
-
- Bronchial asthma
- Epilepsy
- Cardiac conduction abnormalities (bradyarrhythmias)
- Parkinsonism
- Peptic ulcer disease
- May cause significant miosis leading to visual field restriction and difficulty with night vision
- Digital nasolacrimal occlusion after instillation recommended to minimise systemic absorption
Pregnancy
| Aspect | Recommendation |
|---|---|
|
Safety category
|
Limited data; potential risk of systemic absorption affecting fetus |
|
Preferred alternatives
|
Topical beta-blockers (e.g., timolol), prostaglandin analogues if essential |
|
When may be used
|
Only if benefits clearly outweigh risks; obstetric and ophthalmology specialist input mandatory |
|
Monitoring
|
Maternal cholinergic symptoms; fetal growth surveillance |
Lactation
| Aspect | Recommendation |
|---|---|
|
Compatibility
|
Use with caution; insufficient human data |
|
Drug levels in milk
|
Likely low due to minimal systemic absorption; not well studied |
|
Preferred alternatives
|
Topical timolol for glaucoma in lactating women |
|
Infant monitoring
|
Observe for cholinergic effects: poor feeding, excessive salivation, diarrhoea, lethargy, bradycardia |
Elderly
| Aspect | Recommendation |
|---|---|
|
Starting dose
|
0.03% once daily |
|
Titration
|
Slower titration recommended; reassess every 3–4 weeks |
|
Special considerations
|
Increased risk of: cataract progression, retinal detachment, systemic bradycardia, visual field restriction leading to falls |
- Regular fundoscopy and lens examination essential
- Educate regarding reduced night vision from miosis
Major Drug Interactions
| Interacting Drug | Effect | Management |
|---|---|---|
|
Succinylcholine
|
Echothiophate inhibits plasma cholinesterase → prolonged neuromuscular blockade, apnoea |
Avoid — discontinue echothiophate at least 4–6 weeks before elective surgery
|
|
Other cholinesterase inhibitors (e.g., donepezil, rivastigmine, pyridostigmine)
|
Cumulative anticholinesterase toxicity | Avoid concurrent use; if essential, close monitoring for cholinergic crisis |
|
Organophosphate insecticides
|
Additive cholinesterase inhibition | Avoid occupational exposure during treatment |
Moderate Drug Interactions
| Interacting Drug | Effect | Management |
|---|---|---|
|
Beta-blockers (ophthalmic or systemic)
|
Enhanced bradycardia risk | Monitor heart rate; use with caution |
|
Anticholinergic ophthalmics (e.g., tropicamide, cyclopentolate)
|
Antagonises miotic effect of echothiophate | Avoid concomitant use; allow washout period |
|
Systemic anticholinergics (e.g., atropine, oxybutynin)
|
May reduce ocular efficacy | Monitor IOP response |
|
Topical corticosteroid eye drops
|
Combined use may elevate IOP and accelerate cataract | Monitor IOP closely when used together |
|
Carbamate insecticides
|
Additive cholinesterase inhibition | Advise patients to avoid exposure |
Common Adverse Effects
- Ocular stinging and discomfort on instillation
- Persistent miosis
- Blurred vision (especially in dim light)
- Brow ache and periorbital headache
- Conjunctival hyperaemia
- Photophobia
- Tearing (lacrimation)
- Eyelid twitching (myokymia)
Serious Adverse Effects:
| Adverse Effect | Clinical Notes |
|---|---|
|
Systemic cholinergic toxicity
|
Bradycardia, hypotension, bronchospasm, excessive salivation, diarrhoea, arrhythmia — discontinue immediately
|
|
Retinal detachment
|
Higher risk with miotics; urgent ophthalmology referral required |
|
Lens opacities
|
Anterior/posterior subcapsular cataract with prolonged use |
|
Iris cysts
|
More common in children; may regress on discontinuation or with phenylephrine co-administration |
|
Prolonged neuromuscular paralysis
|
If succinylcholine used during anaesthesia without adequate washout |
|
Uveitis exacerbation
|
In predisposed patients |
⚠️ Immediate discontinuation required if signs of systemic toxicity, retinal detachment, or severe ocular inflammation occur.
Monitoring Requirements:
| Timing | Parameters |
|---|---|
|
Baseline
|
Intraocular pressure, gonioscopy, fundoscopy (retinal periphery), lens clarity assessment |
|
During initiation (2–4 weekly)
|
IOP measurement, pupillary response, signs of ocular inflammation |
|
Ongoing (every 3–6 months)
|
Fundoscopy for retinal detachment; slit-lamp for cataract progression |
|
Long-term (6–12 monthly)
|
Comprehensive anterior segment and fundus examination |
|
Special (paediatrics)
|
Systemic cholinergic symptoms at each visit; iris cyst assessment; growth milestones |
Brands in India
- Phospholine Iodide 0.03% ophthalmic solution (limited availability; often imported)
Note: Availability in India is highly restricted. Many centres procure on named-patient basis or through hospital pharmacy compounding. Confirm current availability before prescribing.
Price Range (INR)
| Formulation | Approximate Price |
|---|---|
| 0.03% ophthalmic solution (5 mL) | ₹300–500 (imported/compounded; variable) |
- Not listed under NLEM
- Not under NPPA price control
- Pricing highly variable due to limited supply and import dependency
Clinical Pearls
- Reserve use for glaucoma refractory to first-line agents (prostaglandin analogues, beta-blockers, alpha agonists)
- Pre-anaesthesia alert: Discontinue minimum 4–6 weeks before any surgery requiring succinylcholine; inform anaesthesiologist
- Fundus examination mandatory before initiation and periodically thereafter due to retinal detachment risk
- Nasolacrimal occlusion: Instruct patients to press on inner canthus for 2–3 minutes after instillation to reduce systemic absorption
- Caregiver education essential in paediatric cases — counsel regarding signs of systemic toxicity (diarrhoea, bradycardia, breathing difficulty)
- Night driving: Advise patients about reduced vision in dim light due to persistent miosis
- Not a first-line agent — use only under specialist ophthalmology supervision
Version
RxIndia v1.0 — 02 Feb 2026
References
- CDSCO (product registry and import documentation)
- Indian Pharmacopoeia / National Formulary of India
- AIIMS Ophthalmology Drug Protocols
- Expert consensus from tertiary ophthalmology centres (India)
- Goodman & Gilman's The Pharmacological Basis of Therapeutics, 13th Edition
- API Textbook of Medicine, 21st Edition (relevant pharmacology sections)
- Harrison's Principles of Internal Medicine, 20th Edition
⚖️
Clinical Responsibility
This platform is designed strictly for healthcare professionals. Data provided is synthesized from authoritative pharmacological sources and clinical registries. Do not use for consumer medical decisions. Always verify critical dosing and contraindications with official institutional protocols and peer-reviewed journals.
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