Procaine infiltration

Specific Local Anesthetic Agents. Clinically used local anesthetics and the methods of appHcation are summarized in Table 5. Procaine hydrochloride [51-05-8] (Novocain), introduced in 1905, is a relatively weak anesthetic having along onset and short duration of action. Its primary use is in infiltration anesthesia and differential spinal blocks. The low potency and low systemic toxicity result from rapid hydrolysis. The 4-arninobenzoic acid... 

The answer is d. (Hardman, p T36J The addition of a vasoconstrictor, such as epinephrine or phenylephrine, to certain short-acting, local anesthetics is a common practice in order to prevent the rapid systemic absorption of the local anesthetics, to prolong the local action, and to decrease the potential systemic reactions. Some local anesthetics cause vasodilation, which allows more compound to escape the tissue and enter the blood. Procaine is an ester-type local anesthetic with a short duration of action due to rather rapid biotransformation in the plasma by cholinesterases. The duration of action of the drug during infiltration anesthesia is greatly increased by the addition of epinephrine, which reduces the vasodilation caused by procaine. 

Procaine hydrochloride Novocain) is readily hydrolyzed by plasma cholinesterase, although hepatic metabolism also occurs. It is not effective topically but is employed for infiltration, nerve block, and spinal anesthesia. It has a relatively slow onset and short (1 hour) duration of action. All concentrations can be combined with epinephrine. It is available in dental cartridges with phenylephrine as the vasoconstrictor. 

Lidocaine hydrochloride Xylocaine) is the most commonly used local anesthetic. It is well tolerated, and in addition to its use in infiltration and regional nerve blocks, it is commonly used for spinal and topical anesthesia and as an antiarrhythmic agent (see Chapter 16). Lidocaine has a more rapidly occurring, more intense, and more prolonged duration of action than does procaine. 

Procaine is ineffective when administered through surface application, and is used only by injection. The onset of action for the drug is 2 to 5 minutes, and its duration of action is short. Vasoconstrictors are usually co-administered with this vasodilator drug to delay its absorption and to increase the duration of action. The drug is used for infiltration anesthesia, peripheral nerve block, and spinal anesthesia. 

The choice of local anesthetic for infiltration, peripheral nerve blocks, and central neuraxis (spinal/epidural) blockade is usually based on the duration of action required. Procaine and chloroprocaine are short-acting lidocaine, mepivacaine, and prilocaine have an intermediate duration of action and tetracaine, bupivacaine, levobupivacaine, and ropivacaine are long-... 

Clinical use Because of its poor penetration of intact mucous membranes, procaine is largely ineffective for topical applications and has been mainly used in injection in combination with adrenaline, although in general it has been replaced by other LAs such as lidocaine. For infiltration anesthesia, 0.25 to 0.5 % solutions of procaine have been used in doses up to 600 mg. For peripheral nerve block, a common dose of 500 mg of procaine has been given as a 0.5 to 2.0 % solution. 

Generic Name Procaine Trade Name(s) Novocain Onset of Action Intermediate Duration of Action Short Principle Use(s) Infiltration Peripheral nerve block Spinal... 

This consists in the injection of the local anesthetic into or around the nerve trunk or in the area of its distribution, so as to block off sensory impulses from the operative field. Because fatal effects may arise from the absorption of the anesthetic, the smallest amount of the least-toxic agent that is effective should be employed, under conditions that minimize absorption. Procaine with the addition of epinephrine (1 100,000) is generally preferred. A well-planned technique is important. It is not necessary to flood the entire field of operation, as in the earliest methods, nor even to infiltrate the whole line of incision, as in infiltration anesthesia. It is now aimed at confining the anesthetic mainly to the nerves, by placing it where the nerves chiefly run or injecting it into the nerves themselves. 

The local injection of 0.1 to 2% procaine or other anesthetics blocks the centripetal proprioceptive impulses and thereby relaxes muscular tonus, normal and abnormal, such as spasmodic torticollis. It effects almost instantaneous relief of the pain, stiffness, malposition, and incapacity of fibrositis, lumbago, and acute sprains and fractures. The site of greatest tenderness may be infiltrated with 10 to 30 cc of 1 or 2% procaine hydrochloride. Injected systemically, it relaxes traumatic tetanus and removes decerebrate rigidity, so that spontaneous movements of the limbs and of the respiration return. Its curare action may also be concerned in this effect. It relaxes parkinsonian, but not myotonic, rigidity. 

Local tissue reactions, including inflammation and necrosis, can occur, particularly if local anesthetic formulations containing epinephrine (adrenaline) have been administered. Allergic reactions can also occur and are most commonly associated with the esters (e.g. procaine, see Ch. 2). Neurotoxicity is rare but may occur when 200 ml or more of a local anesthetic is administered by infiltration in a short period. It is more likely that a horse will become ataxic, which can lead to selftrauma, after nerve blockade in the limbs, and severe hindlimb ataxia can follow the caudal... 

Extension of Tropine Alkaloids. Here again, medicinal chemists have gone beyond nature by molecular modification. While cocaine possesses topical anesthetic activity but no local infiltration value as an anesthetic, a number of very useful, local anesthetic agents such as procaine and lidocaine have been derived from our knowledge of the structure of cocaine. Chemists have broadened the scope of usefulness of the cocaine structure. 

Procaine (novocain), the first synthetic local anesthetic, is an amino ester (see Figure 14-1) with low potency, slow onset, and short duration of action. Its use now is confined to infiltration anesthesia and occasionally for diagnostic nerve blocks. Its hydrolysis in vivo produces para-aminobenzoic acid which inhibits the action of sulfonamides. Thus, large doses should not be administered to patients taking sulfonamide drugs. 

The local anesthetics used most frequently for infiltration anesthesia are lidocaine (0.5-1%), procaine (0.5-1%), and bupivacaine (0.125-0.25%). When used without epinephrine, up to 4.5 mg/kg of lidocaine, 7 mg/kg of procaine, or 2 mg/kg of bupivacaine can be employed in adults. When epinephrine is added, these amounts can be increased by one-third. 

It is an all-purpose local anaesthetic drug used frequently in surface infiltration, block, caudal and spinal anaesthesia. It is reported to be 10 times more toxic and potent than procaine, whereas its duration of action is twice than that of procaine. 

It is a local anaesthetic used for infiltration, peridural, nerve block, and caudal anaesthesia. It is found to be twiee as potent as procaine. It has been reported that its duration of action is significantly longer than that of lidocaine, even without adrenaline. Henee, it is of particular importance in subjects showing contraindication to adrenaline. 

Procaine (Novocain) Low potency. Infiltration and spinal anesthesia. Low toxicity. 

Chloroprocaine (N,N -diethylaminoethyl 4-amino-2-chlorobenzoate) is a very short-acting, amino ester-type local anesthetic used to provide regional anesthesia by infiltration as well as by peripheral and central nerve block, including lumbar and caudal epidural blocks. The presence of a chlorine atom ortho to the carbonyl of the ester function increases its rate of hydrolysis by plasma cholinesterase at least threefold compared to procaine and benzocaine. Thus, chloroprocaine may be used in maternal and neonatal patients with minimal placental passage of chloroprocaine. The lower plasma cholinesterase activity in the maternal epidural space must still have sufficient activity for degrading chloroprocaine and, thus, not allowing it to cross the placenta barrier. 

Procaine was one of the first local anesthetics for infiltration and regional anesthesia (See Examples 10.6,10.7)... 

Procaine (its hydrochloride is marketed as Novocain) was one of the first local anesthetics for infiltration and regional anesthesia. See "Chemical Connections From Cocaine to Procaine and Beyond." According to the following retrosynthetic scheme, procaine can be synthesized from 4-aminobenzoic acid, ethylene oxide, and diethylamine as... 

The hydrochloride of procaine is the most commonly used form. It is soluble in water in a 1 1 ratio and in alcohol 1 30. The hydrochloride is insuflidently lipophilic to be used in preparations for topical application to the skin. It is currently used occasionally being administered by infiltration injection. 

---