Carbachol

Carbachol
Systematic (IUPAC) name
2-[(Aminocarbonyl)oxy]-N,N,N-trimethylethanaminium chloride
Clinical data
Trade names Miostat
AHFS/Drugs.com monograph
Pregnancy
category
  • US: C (Risk not ruled out)
Routes of
administration		 Oral-Tablet, Injectable-solution, Topical-eye drops
Legal status
  • ℞ (Prescription only)
Pharmacokinetic data
Bioavailability low
Metabolism ?
Biological half-life ?
Excretion ?
Identifiers
CAS Number 51-83-2 YesY
ATC code N07AB01 (WHO) S01EB02 QA03AB92
PubChem CID 5831
IUPHAR/BPS 298
DrugBank DB00411 YesY
ChemSpider 5626 YesY
UNII 8Y164V895Y YesY
KEGG D00524 YesY
ChEBI CHEBI:3385 YesY
ChEMBL CHEMBL14 YesY
Chemical data
Formula C6H15ClN2O2
Molar mass 182.696 g/mol
  (verify)

Carbachol (Carbastat, Carboptic, Isopto Carbachol, Miostat), also known as carbamylcholine, is a cholinomimetic drug that binds and activates the acetylcholine receptor. Thus it is classified as a cholinergic agonist. It is primarily used for various ophthalmic purposes, such as for treating glaucoma, or for use during ophthalmic surgery. It is generally administered as an ophthalmic solution (i.e. eyedrops).

Chemistry and pharmacology

Carbachol is a choline carbamate and a positively charged quaternary ammonium compound.[1] It is not well absorbed in the gastro-intestinal tract and does not cross the blood–brain barrier. It is usually administered topical ocular or through intraocular injection.[1] Carbachol is not easily metabolized by cholinesterase, it has a two to 5 minute onset of action and its duration of action is 4 to 8 hours with topical administration and 24 hours for intraocular administration. Since carbachol is poorly absorbed through topical administration, benzalkonium chloride is mixed in to promote absorption.[1]

Carbachol is a parasympathomimetic that stimulates both muscarinic and nicotinic receptors.[1] In topical ocular and intraocular administration its principal effects are miosis and increased aqueous humour outflow.[1]

In the cat and rat, carbachol is well known for its ability to induce rapid eye movement (REM) sleep when microinjected into the pontine reticular formation. Carbachol elicits this REM sleep-like state via activation of postsynaptic muscarinic cholinergic receptors (mAChRs).[1]

A recent review indicates that carbachol is a strong promoter of ICC activity, which is mediated through the calcium-activated chloride channel, anoctamin 1.[2]

Indications

Carbachol is primarily used in the treatment of glaucoma, but it is also used during ophthalmic surgery.[1] Carbachol eyedrops are used to decrease the pressure in the eye for people with glaucoma. It is sometimes used to constrict the pupils during cataract surgery.

Topical ocular administration is used to decrease intraocular pressure in people with primary open-angle glaucoma. Intraocular administration is used to produce miosis after lens implantation during cataract surgery. Carbachol can also be used to stimulate bladder emptying if the normal emptying mechanism is not working properly.

In most countries carbachol is only available by prescription. Outside the United States, it is also indicated for urinary retention as an oral (2 mg) tablet.[1][3]

Contraindications

Use of carbachol, as well as all other muscarinic receptor agonists, is contraindicated in patients with asthma, coronary insufficiency, gastroduodenal ulcers, and incontinence. The parasympathomimetic action of this drug will exacerbate the symptoms of these disorders.

Overdose

The effects of a systemic overdose will probably be similar to the effects of a nerve agent (they both act on the cholinergic system, increasing cholinergic transmission), but its toxicity is much weaker and it is easier to antagonize in overdose. When administered ocularly there is little risk of such effects, since the doses are much smaller (see topical versus systemic administration).[4]

References

  1. 1 2 3 4 5 6 7 8 "Carbachol". PubChem Compound. Retrieved 6 March 2014.
  2. ↑ Sanders KM, Zhu MH, Britton F, Koh SD, Ward SM (February 2012). "Anoctamins and gastrointestinal smooth muscle excitability". Exp. Physiol. 97 (2): 200–206. doi:10.1113/expphysiol.2011.058248. PMC 3272164. PMID 22002868.
  3. ↑ "Carbachol generics". ndrugs. Retrieved 6 March 2014.
  4. ↑ Richard A. Harvey; Pamela C. Champe, eds. (2009). Lippincott's Illustrated Review: Pharmacology (4th ed.). Lippincott Williams & Wilkins. p. 49. ISBN 978-0781771559.

External links

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