Physostigmine

Drug #572

Physostigmine is alkaloid having the anticholinesterase activity, obtained from the dried ripe seed of Physostigma venenosum. The pharmacologic properties of it mimic those of acetylcholine. It increases intestinal and bladder motility. Physostigmine is used topically to reduce intra-ocular pressure (IOP) in glaucoma and parenterally to reverse the central nervous system effect produced by overdosage of anticholinergic drugs.

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Primary Characteristics

It is of Natural origin and belongs to Alkaloid.

It belongs to Cholinestrase inhibitor pharmacological group on the basis of mechanism of action and also classified in Cholinergic Agonist pharmacological group. It is also classified under Antidotes .

Molecular Weight: 275.3 · pK_a: 1.8, 7.9 · Solubility in Water: 1 in 1 - 90 · Solubility in Alcohol: 1 in 1 - 25 · Non-proprietary name: Physostigmine.

Pharmacokinetics

Absorption: Physostigmine has an oral bioavailability is 101% (±2.5%), pre-systemic (first-pass) metabolism accounts for 24% (±13%).

Distribution: Physostigmine has a volume of distribution is 15 - 75 litre.

Elimination: plasma half-life is 12 - 40 min.

Indications

Physostigmine is primarily indicated in conditions like Glucoma, Myasthenia gravis, Oversedation, Poisoning with anticholinergic drugs, Poisoning with antidepressant drugs.

Contraindications

Physostigmine is contraindicated in conditions like Anesthesia, Asthma, Diabetes mellitus, Neuromuscular blockade, Parkinsonism, Cardiovascular disease, Gangrene.

Dosage

Physostigmine's dosage details are as follows:

Dose	Single Dose	Frequency	Route	Instructions
Adult Dosage
0.37 %	0.37 %	—	Ophthalmic	As Required
Paediatric Dosage (20kg)
0 – 0	—	—		Safety not established
Neonatal Dosage (3kg)
0 – 0	—	—		Safety not established

Drug Interactions

Unknown4 interactions

Always consult your physician for the change of dose regimen or an alternative drug of choice that may strictly be required.

Side Effects

Physostigmine in overdosage may give rise to further complications which include Convulsions , Hypertension .

Physostigmine produces potentially life-threatening effects which include Asystole . Careful monitoring is needed with proper medical management.

The signs and symptoms that are produced after acute overdosage of Physostigmine are Bradycardia, Respiratory paralysis, Salivation , Cholinergic crisis, Urination, Defecation .

Physostigmine is known to cause more or less tolerable side effects which are usually transient. These include Ciliary & conjnuctival congestion, Headache, Myopia , Ocular & periorbital pain, Twitching lids.

Warnings / Precautions

Physostigmine should be used with caution in patients with eye problems, asthma, intestinal disease, ulcers, low or high blood pressure, heart disease, hyperthyroidism, seizures, Parkinson's disease or an obstruction of the urinary tract. Before having surgery with a general anesthetic, tell the doctor or dentist about the use of the drug. Do not allow any one else to use this medication. This drug should be used during pregnancy only if clearly needed.

Available Brands

None recorded.

Storage Conditions

Physostigmine should be stored Inj.

Drug Classification

1.21.4.1 — Miotics