Characteristics
Cocaine hydrochloride (benzoylmethylecgonine hydrochloride)
occurs naturally as a white crystalline solid that is
highly soluble in water:
1. Used exclusively via topical application. Injection of
cocaine is contraindicated because of the ready availability
of more effective and much less toxic local anesthetics.
Cocaine is an ester local anesthetic.
2. Onset of topical anesthetic action is quite rapid, usually
occurring within 1 minute.
3. Duration of anesthetic action may be as long as 2 hours.
4. Absorbed rapidly but eliminated slowly (elimination
half-life 42 minutes).
5. Undergoes metabolism in the liver and plasma.
6. Unmetabolized cocaine may be found in the urine.
7. Cocaine is the only local anesthetic consistently demonstrated
to produce vasoconstriction, which develops as
a result of its ability to potentiate the actions of endogenous
epinephrine and norepinephrine. Addition of
vasoconstrictors to cocaine is therefore unnecessary and
is potentially dangerous, increasing the likelihood of
dysrhythmias, including ventricular fibrillation.
8. Classified as a Schedule II drug under the Controlled
Substances Act. Repeated use results in psychological
dependence and tolerance.
9. Overdose of cocaine is not uncommon following illicit
use, primarily because the drug is readily absorbed
from mucous membranes and its dosage is not carefully
monitored.
10. Clinical manifestations of mild overdose include
euphoria, excitement, restlessness, tremor, hypertension,
tachycardia, and tachypnea.
11. Clinical manifestations of acute cocaine overdose
include excitement, restlessness, confusion, tremor,
hypertension, tachycardia, tachypnea, nausea and vomiting,
abdominal pain, exophthalmos, and mydriasis;
these are followed by depression (CNS, cardiovascular,
respiratory) and death from respiratory arrest.
12. It is available in concentrations ranging from 1% to
10%.
13. It is recommended that the concentration of cocaine
should not exceed 4% for topical application to oral
mucous membranes.
14. Solutions of cocaine are unstable and deteriorate on
standing.
15. Because of the extreme abuse potential of cocaine, its use
as a topical anesthetic in dentistry is not recommended.
16. Cocaine is occasionally applied topically prior to surgical
procedures by otolaryngologists and ophthalmologists.
