PRECAUTIONS
Drug Abuse And Dependence
TALACEN (pentazocine and acetaminophen) is a Schedule IV controlled substance.
Abuse and addiction are separate and distinct from physical dependence and
tolerance. Abuse is characterized by misuse of a drug for non-medical purposes,
often in combination with other psychoactive substances. Addiction is a disease
of repeated drug abuse. Addiction is a primary, chronic, neurobiologic disease,
with genetic, psychosocial, and environmental factors influencing its development
and manifestations. Addiction is characterized by behaviors that include one
or more of the following: impaired control over drug use, compulsive use, continued
use despite harm, and craving. Drug addiction is a treatable disease, utilizing
a multidisciplinary approach, but relapse is common. Physical dependence is
a state of adaptation that is manifested by a specific withdrawal syndrome that
can be produced by abrupt cessation, rapid dose reduction, decreasing blood
level of the drug, and/or administration of an antagonist. Tolerance is a state
of adaptation in which exposure to a drug induces changes that result in a diminution
of one or more of the drug's effects over time. Tolerance may occur to both
the desired and undesired effects of drugs, and may develop at different rates
for different effects.
Physicians should be aware that addiction may not be accompanied by concurrent
tolerance and symptoms of physical dependence in all addicts. In addition, abuse
of opioids can occur in the absence of addiction and is characterized by misuse
of the drug for non-medical purposes, and often in combination with other psychoactive
substances.
There have been some reports of dependence and of withdrawal symptoms with
TALACEN (pentazocine and acetaminophen) . Patients with a history of drug dependence should be under close supervision
while receiving pentazocine orally. There have been rare reports of possible abstinence syndromes in newborns after prolonged use of pentazocine during pregnancy.
There have been reports of development of addiction and physical dependence
in patients receiving parenteral pentazocine. People with a history of drug
abuse or alcohol abuse may have a higher chance of becoming addicted to opioid
medicines.
Abrupt dose cessation or rapid dose reduction following the extended use of
parenteral pentazocine has resulted in withdrawal symptoms such as abdominal
cramps, nausea, vomiting, elevated temperature, chills, rhinorrhea, restlessness,
anxiety, or lacrimation. In general opioid therapy should not be abruptly discontinued.
When the patient no longer requires treatment with TALACEN (pentazocine and acetaminophen) , the drug should
be tapered gradually to prevent signs and symptoms of withdrawal in patients
who have been receiving opioids for an extended period of time and might have
become physically dependent.
In prescribing TALACEN (pentazocine and acetaminophen) for chronic use, the physician should take under consideration
that proper assessment of the patient, proper prescribing practices, periodic
re-evaluation of therapy, and proper dispensing and storage are appropriate
measures that help to identify and decrease misuse and abuse of opioid drugs.
Severe, even lethal, consequences may result from misuse of tablets by injection
either alone or in combination with other substances, such as pulmonary emboli,
vascular occlusion, ulceration and abscesses, and withdrawal symptoms in narcotic
dependent individuals.
CNS Effect
Caution should be used when TALACEN (pentazocine and acetaminophen) is administered to patients prone to seizures;
seizures have occurred in a few such patients in association with the use of
pentazocine although no cause and effect relationship has been established.
Porphyria
Particular caution should be exercised in administering pentazocine to patients
with porphyria since it may provoke an acute attack in susceptible individuals.
Cardiovascular Disease
Pentazocine can elevate blood pressure, possibly through the release of endogenous
catecholamines. Particular caution should be exercised in conditions where alterations
in vascular resistance and blood pressure might be particularly undesirable,
such as in the acute phase of myocardial infarction.
TALACEN (pentazocine and acetaminophen) should be used with caution in patients with myocardial infarction
who have nausea or vomiting.
Impaired Renal or Hepatic Function
Decreased metabolism of the drug by the liver in extensive liver disease may
predispose to accentuation of side effects. Although laboratory tests have not
indicated that pentazocine causes or increases renal or hepatic impairment,
the drug should be administered with caution to patients with such impairment.
Since acetaminophen is metabolized by the liver, the question of the safety
of its use in the presence of liver disease should be considered.
Other
Caution should also be observed when administering TALACEN (pentazocine and acetaminophen) in patients with
hypothyroidism, adrenocortical insufficiency, prostate hypertrophy, inflammatory
or obstructive bowel disease, acute abdominal syndromes of unknown etiology,
cholecystitis, pancreatitis, or acute alcohol intoxication and delirium tremens.
Biliary Surgery
Narcotic drug products are generally considered to elevate biliary tract pressure
for varying periods following their administration. Some evidence suggests that
pentazocine may differ from other marketed narcotics in this respect (i.e.,
it causes little or no elevation in biliary tract pressures). The clinical significance
of these findings, however, is not yet known.
Carcinogenesis, Mutagenesis, Impairment of Fertility
Carcinogenesis, mutagenesis, and impairment of fertility studies have not been
done with this combination product.
Studies to evaluate the mutagenic potential of the components of TALACEN (pentazocine and acetaminophen) have
not been conducted.
Pentazocine, when administered orally or parenterally, had no adverse effect
on either the reproductive capabilities or the course of pregnancy in rabbits
and rats. Embryotoxic effects on the fetuses were not shown.
The daily administration of 4 mg/kg to 20 mg/kg pentazocine subcutaneously
to female rats during a 14 day pre-mating period and until the 13th day of pregnancy
did not have any adverse effects on the fertility rate.
Pregnancy
Teratogenic Effects
Pregnancy Category C
There are no adequate and well-controlled studies in pregnant women. TALACEN (pentazocine and acetaminophen)
should be used during pregnancy only if the potential benefit justifies the
potential risk to the fetus.
Animal studies with the combination of pentazocine and acetaminophen have not
been completed.
In a published report, a single dose of pentazocine administered to pregnant
hamsters on gestation day 8 increased the incidence of exencephaly and cranioschisis
at a dose of 196 mg/kg, SC (0.2-times the maximum daily human dose of pentazocine
via 6 caplets on a mg/m² basis).
Nonteratogenic Effects
There has been no experience in this regard with the combination pentazocine
and acetaminophen. However, there have been rare reports of possible abstinence
syndromes in newborns after prolonged use of pentazocine during pregnancy. Frequent
use of acetaminophen (defined as most days or daily use) in late pregnancy may
be associated with an increased risk of persistent wheezing in the infant which
may persist into childhood.
Labor and Delivery
Patients receiving pentazocine during labor have experienced no adverse effects
other than those that occur with commonly used analgesics. However, pentazocine
can cross the placental barrier and cause central nervous system depression
in the newborn and, if used regularly throughout pregnancy, may lead to symptoms
of withdrawal in the newborn. TALACEN (pentazocine and acetaminophen) should be used with caution in women delivering
premature infants. The effect of TALACEN (pentazocine and acetaminophen) on the mother and fetus, the duration
of labor or delivery, the possibility that forceps delivery or other intervention
or resuscitation of the newborn may be necessary, or the effect of TALACEN (pentazocine and acetaminophen) ,
on the later growth, development, and functional maturation of the child are
unknown at the present time.
Nursing Mothers
Pentazocine and acetaminophen are excreted in human milk. Caution should be
exercised when TALACEN (pentazocine and acetaminophen) is administered to a nursing woman.
Pediatric Use
Safety and effectiveness in pediatric patients below the age of 12 have not
been established.
Geriatric Use
Clinical studies of TALACEN (pentazocine and acetaminophen) did not include sufficient numbers of subjects
aged 65 and over to determine whether they respond differently from younger
subjects. Other reported clinical experience has not identified differences
in responses between the elderly and younger patients. In general, dose selection
for an elderly patient should be cautious, usually starting at the low end of
the dosing range, reflecting the greater frequency of decreased hepatic, renal,
or cardiac function, and of concomitant disease or other drug therapy.