carbachol ophthalmic

Action and Spectrum

Drug Interaction

Adverse Reaction

Frequency not defined 

Systemic 

Epigastric distress 

Arrhythmia 

Syncope 

Salivation 

Asthma 

Headache 

Tightness in the urinary bladder 

Abdominal cramps 

Flushing 

Hypotension 

Epigastric stress 

Vomiting 

Diaphoresis 

Sweating 

Ocular 

Stinging (transient) 

Bullous keratopathy 

Postoperative iritis following cataract extraction 

Corneal clouding 

Ciliary spasm 

Persistent bullous keratopathy 

Retinal detachment (rare) 

Black Box Warning

Actions and Spectrum: 

• carbachol is a cholinergic agonist that acts on muscarinic and nicotinic acetylcholine receptors. It is a synthetic analog of acetylcholine and has a longer duration of action than acetylcholine. 
• carbachol activates muscarinic receptors in smooth muscle, glandular tissue, and the heart. This leads to an increase in smooth muscle contraction, glandular secretion, and a decrease in heart rate. carbachol also activates nicotinic receptors in the autonomic ganglia, increasing sympathetic and parasympathetic nervous system activity. 
• carbachol has a broad spectrum of activity and is used for various medical purposes, including: 
• Ophthalmology: carbachol is used to treat glaucoma by decreasing intraocular pressure. It stimulates muscarinic receptors in the ciliary muscle, leading to increased drainage of aqueous humor from the eye. 

Contraindication / Caution

Contraindications/caution: 

Contraindications: 

• Hypersensitivity: Individuals with known hypersensitivity or allergy to carbachol or other ingredients in the medication should not use it. 
• Asthma or chronic obstructive pulmonary disease (COPD): carbachol can cause bronchoconstriction, making it unsuitable for individuals with asthma or COPD. 
• Cardiovascular diseases: carbachol can cause bradycardia and other cardiac side effects, making it unsuitable for individuals with cardiovascular diseases, such as bradycardia, heart block, or unstable angina. 
• Peptic ulcer disease: carbachol can increase the secretion of gastric acid, making it unsuitable for individuals with a history of peptic ulcer disease. 
• Urinary obstruction: carbachol can increase bladder and urethral tone, making it unsuitable for individuals with urinary obstruction. 
• Pregnancy and breast-feeding: The safety of carbachol ophthalmic solution in pregnant or breast-feeding individuals has not been established, and it should be used with caution in such cases. 

Caution: 

• Cardiovascular disease: carbachol can cause bradycardia and other cardiac side effects, making it essential to use it cautiously in individuals with cardiovascular diseases, such as bradycardia, heart block, or unstable angina. 
• Respiratory disease: carbachol can cause bronchoconstriction, making it essential to use cautiously in individuals with asthma or COPD. 
• Gastrointestinal disease: carbachol can increase gastric acid secretion, making it essential to use it with caution in individuals with a history of peptic ulcer disease or other gastrointestinal disorders. 
• Parkinson’s disease: carbachol can exacerbate the symptoms of Parkinson’s disease, making it essential to use it with caution in individuals with this condition. 

Pregnancy / Lactation

Pregnancy consideration: Insufficient data available 

Lactation: Excretion of the drug in human breast milk is unknown 

Pregnancy category: 

Category A: well-controlled and Satisfactory studies show no risk to the fetus in the first or later trimester.   

Category B: there was no evidence of risk to the fetus in animal studies, and there were not enough studies on pregnant women. 

Category C: there was evidence of risk of adverse effects in animal reproduction studies, and no adequate evidence in human studies must take care of potential risks in pregnant women.    

Category D: adequate data with sufficient evidence of human fetal risk from various platforms, but despite the potential risk, and used only in emergency cases for potential benefits.    

Category X: Drugs listed in this category outweigh the risks over benefits. Hence these categories of drugs need to be avoided by pregnant women.    

Category N: There is no data available for the drug under this category 

Pharmacology

Pharmacology: 

carbachol ophthalmic is a medication used to treat certain types of glaucoma by reducing intraocular pressure. It is a cholinergic agonist that acts on muscarinic and nicotinic acetylcholine receptors.  

carbachol acts as a direct-acting cholinergic agonist that stimulates muscarinic receptors in the eye’s ciliary muscle, leading to increased aqueous humor drainage and decreased intraocular pressure. 

Pharmacodynamics: 

carbachol ophthalmic is a medication used to treat certain types of glaucoma by reducing intraocular pressure. Its pharmacodynamic effects are related to its mechanism of action as a cholinergic agonist that acts on muscarinic and nicotinic acetylcholine receptors. Here are some critical aspects of the pharmacodynamics of carbachol ophthalmic 

• Muscarinic receptor activation: carbachol stimulates muscarinic receptors in the eye’s ciliary muscle, leading to increased aqueous humor drainage and decreased intraocular pressure. 
• Nicotinic receptor activation: carbachol also stimulates nicotinic receptors in the ciliary muscle, leading to muscle contraction and further facilitating aqueous humor drainage. 
• Parasympathomimetic effects: carbachol acts as a parasympathomimetic agent, mimicking the effects of the parasympathetic nervous system on the ciliary muscle and other structures of the eye. 

• Effects on other tissues: carbachol may also affect other tissues in the body, including the respiratory and cardiovascular systems, through its actions on cholinergic receptors in these tissues. 
• Dose-response relationship: The pharmacodynamic effects of carbachol ophthalmic are dose-dependent, with higher doses generally resulting in more significant reductions in intraocular pressure. 

Pharmacokinetics: 

Absorption 

carbachol is typically administered via injection or eye drops. When given by injection, it is rapidly absorbed into the bloodstream. When given as eye drops, it is absorbed through the cornea and can enter the systemic circulation.  

Distribution 

Once absorbed, carbachol is distributed throughout the body. It can cross the blood-brain barrier and reach the central nervous system, where it exerts its pharmacological effects. It can also cross the placenta and reach the fetus.  

Metabolism 

carbachol is rapidly metabolized by cholinesterase enzymes in the plasma and tissues. It has a short half-life of only a few minutes.  

Elimination and Excretion 

The metabolites of carbachol are primarily excreted in the urine. Most of the drug is eliminated from the body within a few hours of administration. 

Adminstartion

Administration: 

Topical solution:  

To minimize drainage to the nose and throat, after administration, apply finger pressure to the lacrimal sac; and remove excess solution from the eye and hand.  

Intraocular Injection: 

Use a 21-gauge needle to draw the correct quantity through a 0.45-micron filter supplied by the manufacturer into a sterile disposable syringe. Remove the associated needle and filter from the syringe before administering and replace them with an appropriate atraumatic cannula for intraocular irrigation. Gentle instillation parallel to the iris face and tangential to the pupil border is recommended. Discard any leftovers. 

Patient Information Leaflet

Patient information leaflet 

Generic Name: carbachol ophthalmic 

Pronounced:  [ KAR-ba-kall ] 

Why do we use carbachol ophthalmic? 

• carbachol ophthalmic is a medication primarily used to treat glaucoma and intraocular hypertension. It works by decreasing intraocular pressure by increasing fluid outflow from the eye. 
• In addition to treating glaucoma and intraocular hypertension, carbachol ophthalmic is sometimes used during certain eye surgeries to constrict the pupil and improve surgical field visualization.