chloroprocaine

Action and Spectrum

Actions and Spectrum: 

chloroprocaine is a local anesthetic agent primarily used for regional anesthesia and pain management. It blocks the generation and also conduction of nerve impulses, leading to a reversible loss of sensation in the area where it is applied.  

• Action: chloroprocaine belongs to the ester group of local anesthetics. It works by inhibiting the voltage-gated sodium channels in nerve cell membranes. By blocking these channels, chloroprocaine prevents the influx of sodium ions into the nerve cells, which is necessary for generating and propagating nerve impulses. This blockade of sodium channels results in the temporary loss of sensation and pain relief in the area where chloroprocaine is administered. 
• Spectrum: chloroprocaine has a relatively short duration of action compared to other local anesthetics. It is classified as an intermediate-acting local anesthetic. The onset of action of chloroprocaine is rapid, usually within a few minutes after administration, and its effects typically last for about 30 minutes to 2 hours, depending on the dose and the site of administration. 

Drug Interaction

Adverse Reaction

Frequency defined 

>10% 

Procedural pain (16%) 

1-10% 

Injection site pain (3.7%) 

Hypotension (4.9%) 

Frequency not defined 

Tinnitus 

Blurred vision 

Excitation 

Depression 

Bradyarrhythmia 

Dizziness 

Anxiety 

Tremor 

Hypotension 

Seizure 

Restlessness 

Anaphylaxis 

Cardiac arrest 

Respiratory arrest 

Black Box Warning

Black Box Warning: 

None 

Contraindication / Caution

Contraindication/Caution: 

Contraindication 

Certain common contraindications for chloroprocaine: 

• Hypersensitivity: Individuals with known hypersensitivity or allergy to chloroprocaine or other ester-type local anesthetics should not receive chloroprocaine. Allergic reactions can range from mild-severe anaphylaxis, a potentially life-threatening allergic reaction. 
• Previous adverse reactions: If a patient has previously experienced significant adverse reactions to chloroprocaine or other ester-type local anesthetics, such as severe allergic reactions or neurologic complications, the use of chloroprocaine should be avoided. 
• Porphyria: chloroprocaine is contraindicated in individuals with a history of porphyria, a group of rare genetic disorders that affect heme production, a hemoglobin component. chloroprocaine can potentially trigger or worsen porphyria symptoms in these patients. 
• Infection at the injection site: chloroprocaine should not be administered if there is an active infection at or near the intended injection site. Injecting chloroprocaine into an infected area can potentially spread the infection or cause further complications. 
• Pre-existing neurological conditions: Individuals with pre-existing neurological conditions, such as multiple sclerosis or peripheral neuropathy, may be at an increased risk of neurologic complications from chloroprocaine. The decision to use chloroprocaine in these patients should be made carefully, weighing the potential benefits against the risks. 
• Bleeding disorders: chloroprocaine can inhibit platelet function and interfere with blood clotting. It should be used cautiously or avoided in patients with known or suspected bleeding disorders, as it can increase the risk of bleeding at the injection site or other bleeding-related complications. 
• Severe cardiovascular disease: Patients with severe cardiovascular disease, including significant heart rhythm disturbances or unstable angina, may be at an enhanced risk of adverse cardiovascular effects with chloroprocaine. Close monitoring and careful consideration of alternative options are necessary in such cases. 

Caution 

Some specific cautions and precautions should be taken into account. These include: 

• Systemic toxicity: chloroprocaine, like other local anesthetics, can potentially cause systemic toxicity if absorbed into the bloodstream in large amounts. This can lead to central nervous system (CNS) and cardiovascular effects. Caution should be exercised to avoid exceeding the recommended dose or inadvertently injecting chloroprocaine intravascularly. 
• Neurologic effects: Local anesthetics, including chloroprocaine, can potentially cause neurologic complications. This can include nerve damage, persistent numbness or weakness, spinal cord injury, or temporary bladder or bowel control loss. Careful and precise administration techniques, appropriate dosing, and continuous monitoring are essential to minimize the risk of such complications. 
• Hypotension: chloroprocaine can cause a drop in blood pressure, leading to hypotension. Patients with pre-existing hypotension or hemodynamically unstable patients should be closely monitored during chloroprocaine administration. Adequate fluid resuscitation and measures to maintain blood pressure may be necessary. 
• Allergic reactions: While rare, allergic reactions to chloroprocaine can occur. Close monitoring for signs of hypersensitivity, such as rash, itching, swelling, or difficulty breathing, is essential. Immediate medical attention should be sought if an allergic reaction is suspected. 
• Methemoglobinemia: In rare cases, chloroprocaine can cause methemoglobinemia, a condition in which the oxygen-carrying capacity of blood is reduced. This can result in cyanosis (bluish skin discoloration) and potentially severe complications. Patients with a history of methemoglobinemia or those more susceptible to this condition should be closely monitored. 
• Pregnancy and lactation: The safety of chloroprocaine during pregnancy and breastfeeding has not been established. It should be used cautiously in pregnant or breastfeeding women, and the potential benefits and risks should be carefully evaluated. 
• Interaction with other medications: chloroprocaine may interact with certain medications, such as beta-blockers or antiarrhythmic drugs, potentially leading to adverse effects.

Pregnancy / Lactation

Pregnancy consideration:  

US FDA pregnancy category: Not assigned. 

Lactation:   

Excreted into human milk: Not known. 

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: 

chloroprocaine is a local anesthetic of the ester group that blocks voltage-gated sodium channels in nerve cell membranes, inhibiting the generation and conduction of nerve impulses. It has a rapid onset of action and a relatively short duration of action, making it suitable for shorter procedures.

Plasma cholinesterases metabolize chloroprocaine to form para-aminobenzoic acid (PABA) and diethylaminoethanol (DEAE), metabolized and excreted primarily in the urine. While chloroprocaine is generally well-tolerated, systemic toxicity can occur if absorbed in large amounts, leading to CNS and cardiovascular effects. Careful administration and monitoring are essential to ensure its safe and effective use. 

Pharmacodynamics: 

Mechanism of action: Local anesthetics function by impeding the generation and conduction of nerve impulses by diminishing sodium permeability and elevating the threshold for the action potential. 

Pharmacokinetics: 

Absorption 

chloroprocaine can be administered via various routes, including infiltration, nerve blocks, and epidural injection. After local administration, chloroprocaine is rapidly absorbed into the systemic circulation. The absorption rate depends on the injection site’s vascularity and the dose administered. 

Distribution 

Once absorbed into the bloodstream, chloroprocaine distributes throughout the body. It has a relatively small distribution volume, suggesting limited extravascular tissue binding. The distribution is influenced by factors such as protein binding and tissue perfusion. 

Metabolism 

chloroprocaine is primarily metabolized by plasma cholinesterases (pseudocholinesterases). It undergoes ester hydrolysis, forming para-aminobenzoic acid (PABA) and diethylaminoethanol (DEAE). PABA is further metabolized in the liver through acetylation and conjugation reactions. 

Elimination and Excretion 

The metabolites of chloroprocaine, including PABA and DEAE, are primarily eliminated in the urine. The elimination half-life of chloroprocaine is relatively short, usually 20 to 60 minutes. The exact rate of excretion and clearance can vary depending on factors like the patient’s renal function and dosage. 

Adminstartion

Administration: 

Intrathecal Administration 

Healthcare professionals typically administer chloroprocaine in a clinical setting. The specific administration technique and dosage may vary depending on the type of procedure, patient factors, and the healthcare provider’s preference.  

• Preparation: Before administering chloroprocaine, the healthcare provider will gather the necessary equipment, including sterile needles, syringes, and local anesthetic vials. They will ensure that the vial of chloroprocaine is intact and check the expiration date. 
• Patient positioning: The patient will be positioned appropriately based on the procedure. For example, if it is a peripheral nerve block, the patient’s limb may need to be positioned and supported adequately. 
• Skin preparation: The skin at the intended injection site will be generally cleaned with an antiseptic solution to reduce the risk of infection. 
• Local anesthesia technique: The specific technique for administering chloroprocaine depends on the type of anesthesia being performed. Common techniques include: 
• Infiltration anesthesia: Chloroprocaine may be injected directly into the tissues surrounding the surgical site to provide local anesthesia. Multiple injections may be needed to cover the desired area adequately. 
• Nerve block anesthesia: chloroprocaine can be injected near a specific nerve or nerve plexus to block the transmission of pain signals from that area. The injection is typically guided by palpation or ultrasound imaging to ensure accurate placement of the needle. 
• Epidural anesthesia: In epidural anesthesia, chloroprocaine is injected into the epidural space, which generally surrounds the spinal cord within the spinal column. This technique is commonly used for labor and delivery or lower abdominal surgeries. 
• Dose and volume: The dose and volume of chloroprocaine administered depend on various factors, including the patient’s age, weight, the desired level of anesthesia, and the specific procedure. The healthcare provider will calculate and administer the appropriate dose, considering the maximum recommended dose for the specific route of administration. 
• Monitoring: After administering chloroprocaine, the patient will be closely monitored for any adverse reactions, such as allergic reactions, changes in blood pressure or heart rate, or neurologic complications. Vital signs, oxygen saturation, and ECG monitoring may be employed during and after the administration. 

Patient Information Leaflet

Patient information leaflet 

Generic Name: chloroprocaine 

Pronounced: [ klor-oh-PROE-kane ] 

Why do we use chloroprocaine? 

chloroprocaine is a local anesthetic primarily used for regional anesthesia and pain management. 

• Obstetric anesthesia: chloroprocaine is frequently used for epidural anesthesia during labor and delivery. 
• Peripheral nerve blocks: chloroprocaine is employed for various peripheral nerve blocks to provide local anesthesia for surgical procedures or to manage acute/chronic pain. It can be used for nerve blocks such as brachial plexus, intercostal, or sciatic nerve blocks. 
• Minor surgical procedures: Due to its relatively short duration of action, chloroprocaine is commonly used for shorter surgical procedures. These can include dental procedures, minor dermatological surgeries, or other procedures that require local anesthesia for a limited time. 
• Diagnostic procedures: chloroprocaine can provide local anesthesia during diagnostic procedures such as bronchoscopy, cystoscopy, or hysteroscopy. It helps to minimize discomfort or pain experienced by the patient during these procedures. 
• Pain management: chloroprocaine may be employed for pain management in acute or chronic conditions. It can be administered as a nerve block or infiltrated directly into the tissues surrounding the pain site to relieve temporary pain.