Pentazocine Hydrochloride

Pentazocine Hydrochloride is used for: Moderate to severe pain

Oral Moderate to severe pain Adult: 50-100 mg every 3-4 hrs; max 600 mg daily. Hepatic impairment: Reduce dose or avoid in liver disease.

Oral Moderate to severe pain Child: 6-12 yr: 25 mg every 3-4 hr.

Renal impairment: CrCl (ml/min) Dosage Recommendation 10-50 75% normal dose. <10 50% normal dose.

Should be taken with food. Take after meals.

Head injury; narcotic dependence; respiratory depression; raised intracranial pressure; MI; heart failure; arterial or pulmonary hypertension; porphyria; pregnancy (prolonged use or high doses at term).

May precipitate withdrawal in narcotic addicts. Impaired respiratory, renal and hepatic function; morbidly obese patients; thyroid dysfunction; prostatic hyperplasia or urinary stricture; biliary tract impairment; adrenal insufficiency (including Addison's disease); abdominal conditions. Elderly or debilitated patients; seizure-prone patients; children and infants (safety and efficacy not established in <1 yr); lactation. May impair ability to drive or operate machinery. Administer IM rather than SC (when frequent inj are needed) and inj sites should be varied. Lactation: unknown if excreted in breast milk, use caution

Pregnancy Prolonged use of opioid analgesics during pregnancy can cause neonatal opioid withdrawal syndrome; there are no available data in pregnant women to inform a drug associated risk for major birth defects and miscarriage; published studies with morphine use during pregnancy have not reported a clear association with morphine and major birth defects Prolonged use of opioid analgesics during pregnancy for medical or nonmedical purposes can result in physical dependence in the neonate and neonatal opioid withdrawal syndrome shortly after birth; the onset, duration, and severity of neonatal opioid withdrawal syndrome vary based on specific opioid used, duration of use, timing and amount of last maternal use, and rate of elimination of drug by newborn; observe newborns for symptoms of neonatal opioid withdrawal syndrome and manage accordingly Severe fetal bradycardia reported when administered during labor; naloxone may reverse these effects; although there are no reports of fetal bradycardia earlier in pregnancy, it is possible it may occur; drug should be used in pregnancy only if clearly needed, if potential benefit outweighs risk to fetus, and if appropriate measures such as fetal monitoring are taken to detect and manage potential adverse effect on fetus Labor or delivery Opioids cross placenta and may produce respiratory depression and psycho-physiologic effects in neonates; an opioid antagonist, such as naloxone, must be available for reversal of opioid induced respiratory depression in neonate; drug is not recommended for use in women during and immediately prior to labor, when use of shorter-acting analgesics or other analgesic techniques are more appropriate; opioid analgesics can prolong labor through actions that temporarily reduce strength, duration, and frequency of uterine contractions; however, this effect is not consistent and may be offset by an increased rate of cervical dilatation, which tends to shorten labor; monitor neonates exposed to opioid analgesics during labor for signs of excess sedation and respiratory depression Infertility Due to effects of androgen deficiency, chronic use of opioids may cause reduced fertility in females and males of reproductive potential; it is not known whether effects on fertility are reversible Lactation Drug is present in breast milk; published lactation studies report variable concentrations of drug in breast milk with administration of immediate-release formulation to nursing mothers in early postpartum period The developmental and health benefits of breastfeeding should be considered along with mother’s clinical need for therapy; capsules and any potential adverse effects on breastfed infant from therapy or from underlying maternal condition Monitor infants exposed to drug through breast milk for excess sedation and respiratory depression; withdrawal symptoms can occur in breastfed infants when maternal administration of an opioid analgesic is stopped, or when breast- feeding is stopped

Depressant affects potentiated by alcohol, CNS depressants; concurrent use with fluoxetine may lead to diaphoresis, ataxia flushing and tremor associated with serotonin syndrome.

Side effects of Pentazocine Hydrochloride : Physical dependence; sedation, dizziness, euphoria, lightheadedness, alterations of mood; respiratory depression; visual hallucinations, disorientation, confusion; hypertension, tachycardia, circulatory depression; shock; hypotension; nausea, vomiting, constipation; seizures, diaphoresis; rash; blood dyscrasias; local tissue damages (SC), muscle fibrosis (IM). Potentially Fatal: Respiratory depression, hypotension, circulatory failure, deepening coma, convulsions.

Pentazocine is a benzomorphan derivative with mixed opioid agonist and antagonist actions. It alters perception of and response to pain and produces generalised CNS depression by binding to opiate receptors in the CNS and acting as a partial agonist/antagonist.