Interacting drugs- summary

Local anesthetics +

Sedatives

 if employed to reduce patient apphrension during dental procedures, use reduced doses, since loacl anesthetics used in combination with CNS depressants may have additive effects. Give young children minimal dose of each agent

Sulfonamides

 the para- aminobenzoic acid metabolite of procaine,chloroprocaine and tetracaine inhibits the action of sulfonamides. Therefore do not use procaine, or tetracaine in any condition in which a sulfonamide drug is employed 

Cimetidine/ranitidine

Decreased clearance with cimetidine and ranitidine.

Lignocaine/mepivacine

Potentiates lignocaine and mepivacaine. Prior use of chlorprocaine may interfere with susequent use of bupivacaine

Infiltration block Caudal epidural lumbar anaethesia 

Cardiac arrest.

CNS excitation may be followed by depression

. Hypotension, bradycardia, arrhythmias and arrest, methhaemoglobinaemia.

Hypersensitivity. Prolonged block.

Dermatologic-

cutaneous lesions, urticaria, pruritus, erythema, angioneurotic edema, sneezing, syncope, excessive sweating, elevated temperature

CNS-

restlessness, anxiety dizziness, tinnitus, blurred vision, nausea, vomiting, chills, pupil constriction or trmors may occur.

Cardiovascular-

myocardial depression, hypotension, decreased cardiac output, herat block, syncope, bradycardia ventricular arrhythmias

Respiratory-

respiratory impairment or paralysis, dueto level of anesthesia (spinal ) extending to upper thoraic and cervical segments

Miscellaneous-

occasional intentional penetration of the subarachoid space by the catheter may occur.

Hypersens to local anaesthetics of amide type.IV regional anaesthesia.

Special precautions:

Pregnancy, severe hepatic disease.

CVS disease.

Dosage- use the lowest dosage that results in effective anesthesia to avoid high plasma levels and serious adverse effects.

Inflammation or sepsis- use local anesthetic procedures with caution when there is inflammation or sepsis. in the region of the proposed injection.

CNS toxicity- monitor cardiovascular and respiratory vital signs and state of consciousness after each injection.

Special risks patients- debilated persons, acuely ill patients , children, obstertic delivery patients and patients with increased intra-abdominal pressure .

Malignant hyperthermia- many drugs used during ansthesia are considered potential triggering agents for familial malignant hyperthermia.

Vasoconstrictors- use sloutions containg vasoconstrictors with caution and in carefully circumscribed quantities in areas of body supplied by end arteries or having otherwise compromised blood supply (eg. digits, nose, external ear, penis) Intravenous regional anesthesia- cardiac arrest and death are reported with the use of bupivacaine for IV anesthesia.  Bupivacaine is not recommended for this technique

Warnings-

Hypersenstivity reactions- including anaphylaxis may occurv in small segment of the population allergic to para-aminobenzoic acid derivatives (eg procaine, tetracaine, benzocaine)

Renal function impairment- use mepivacaine with caution in patients with renal disease. Hepatic function impairment- becausee amide-type local anesthetics are metabolised primarily in the liver, patients with hepatic disease, especially severe hepatic disease, may be more susceptible to potential toxicity

Elderly- repeated doses may cause accumulation of the drug or or its metabolites or slow metabolic degradation

Pregnancy- safety for use in pregnant women other than those in labor has not been established

Lactation- safety for use in nursing mother has not ben established.

Children- due to lack of clinical experience the administration of bupivacaine to children < 12 years of age is not recommended. Safety and efficacy of tetracaine in children have not been established

Indication-

Infiltration block Caudal epidural lumbar anaethesia

See literature

Dosage-

smallest dose and concentration to produce desired result should be administered

1. When appropiate inform patients in advance that they may experience temporary loss of sensation, and motor activity, usually in the lower halfof the body, following proper administration of caudal or epidural anaesthesia

Pharmacology-

These agents prevent generation and conduction of nerve impluses by inhibiting ionic fluxes, increasing electrical excitation threshold.slowing nerve impulse propagation and reducing rate of rise of action potential

Pharmcokinetics-

The onset of local anesthesia is dependent on the dissociation constant (pKa) lipid solubility, pH at the injection site protein binding and molecular size.

Pregnancy-

Safety for use in pregnant women other than those in labor has not been established

Lactation-

Safety for use in nursing mother has not ben established.

Children-

Due to lack of clinical experience the administration of bupivacaine to children < 12 years of age is not recommended. Safety and efficacy of tetracaine in children have not been established