Pentazocine toxicity

Toxicity. The estimated minimum lethal dose is 0.3 g, although recovery after ingestion of 1.2 g has been reported. Blood concentrations of 1 pg/ml or more may be lethal. Some cases of abuse have been reported resulting in a mild form of addiction. Pentazocine abuse has been reported to be widespread among street addicts in the United States of America, in combination with tripelennamine ( T s and Blues ). 

There is increased toxicity in patients who take pentazocine with alcohol, antihistamines, or CNS depressants one patient developed opioid pulmonary edema and one died (15). 

Acute toxicity induced by pentazocine is primarily associated with central nervous system (CNS) effects that include dizziness, anxiety, hallucinations, mood alterations, and seizures. Respiratory depression, increased PaCOi levels, pulmonary edema, and apnea may occur. Tachycardia, increased systolic and diastolic blood pressure, pinpoint pupils, nausea, vomiting, and abdominal pain have also been reported. In a recently published case series, 40% of acute pentazocine overdose patients did not have the classic opioid toxidrome of CNS and respiratory depression with miosis. 

Administration of opioids for chronic arthritic pain in elderly people is effective but can be associated with problematic adverse reactions, particularly morphine and related compounds in those with chronic renal insufficiency [53 ]. There is a higher frequency of nausea, constipation, and cognitive impairment. Pethidine, dextro-propoxyphene, and pentazocine should also be avoided because they have toxic metabolites. Preferred alternatives are hydro-morphone, oxycodone, and oxymorphone. 

Kane and Pokorny (27" ) have reviewed mental and emotional disturbances with pentazocine use, pointing out that severe mental and emotional disturbance, as well as addiction, may occur. The accumulated data showed that depressive states were reported most frequently, while toxic psychoses, hallucinogenic reactions with panic, and paranoid states on withdrawal of the drug were less frequent. Of 197 cases of addiction reported to date, only 6 were related to oral use of the drug. The abstinence syndrome was mild, consisting usually of restlessness, nausea, cramps and insomnia. Convulsions had been reported on 4 occasions. The authors thought that euphoria and psycho-... 

Hunter, J. A. A. and Davison, A. M. (1973) Toxic epidermal necrolysis associated with pentazocine therapy and severe reversible renal failure. Brit. J. Dermatol, 88, 287. 

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