2-オキソピロリジン-1-アセトアミド

Drug-Induced Liver Injury Severity and Toxicity (DILIst)

Piracetam

DILI Positive

DOI:10.1016/j.drudis.2019.09.022

/LABORATORY ANIMALS: Acute Exposure/ Acute toxicological studies in animals showed lethal doses were obtained in mice (18.2 g/kg and higher) but not in rats and dogs dosed respectively at 21 g/kg or 10 g/kg.

/LABORATORY ANIMALS: Chronic Exposure or Carcinogenicity/ The only change which might eventually be attributed to chronic treatment in male, but not in female, rats was an increase of the incidence over control animals of progressive glomerulonephrosis at the dose of 2.4 g/kg/day given for 112 weeks.

/LABORATORY ANIMALS: Chronic Exposure or Carcinogenicity/ Repeated oral treatment for up to 1 year in dogs (10 g/kg) and 6 months in rats (2 g/kg) was very well tolerated: no target organ toxicity or signs of (irreversible) toxicity were clearly demonstrated.

/LABORATORY ANIMALS: Developmental or Reproductive Toxicity/ Although piracetam crosses the placenta into the fetal circulation, no teratogenic effects were observed at dose levels up to 4.8 g/kg/day (mice, rats) and 2.7 g/kg/day (rabbits). Furthermore, the compound affects neither fertility nor the peri- or postnatal development of the pregnancy at doses up to 2.7 g/kg/day.

/GENOTOXICITY/ Piracetam was found to be devoid of any mutagenic or clastogenic activity and does not represent any genotoxic ... risk to man.

While data specific to piracetam were not located(SRC, 2007), the literature suggests that some pharmaceutically active compounds originating from human and veterinary therapy are not eliminated completely in municipal sewage treatment plants and are therefore discharged into receiving waters(1). Wastewater treatment processes often were not designed to remove them from the effluent(2). Selected organic waste compounds may be degrading to new and more persistent compounds that may be released instead of or in addition to the parent compound(2).

/SRP:/ Basic treatment: Establish a patent airway (oropharyngeal or nasopharyngeal airway, if needed). Suction if necessary. Watch for signs of respiratory insufficiency and assist ventilations if needed. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for pulmonary edema and treat if necessary ... . Monitor for shock and treat if necessary ... . Anticipate seizures and treat if necessary ... . For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with 0.9% saline (NS) during transport ... . Do not use emetics. For ingestion, rinse mouth and administer 5 ml/kg up to 200 ml of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool ... . Cover skin burns with dry sterile dressings after decontamination ... . /Poisons A and B/

/SRP:/ Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in severe respiratory distress. Positive-pressure ventilation techniques with a bag valve mask device may be beneficial. Consider drug therapy for pulmonary edema ... . Consider administering a beta agonist such as albuterol for severe bronchospasm ... . Monitor cardiac rhythm and treat arrhythmias as necessary ... . Start IV administration of D5W /SRP: "To keep open", minimal flow rate/. Use 0.9% saline (NS) or lactated Ringer's if signs of hypovolemia are present. For hypotension with signs of hypovolemia, administer fluid cautiously. Watch for signs of fluid overload ... . Treat seizures with diazepam or lorazepam ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Poisons A and B/

The plasma half life of piracetam is approximately 5 hours following oral or intravenous administration. The half life in the cerebrospinal fluid was 8.5 hours.

... The plasma half-life is 5.0 hours, in young adult men.

As large proportion of total piracetam administered is excreted as unchanged drug, there is no known major metabolism of piracetam.

... No metabolite of piracetam has been found.

Drugs intended to prevent damage to the brain or spinal cord from ischemia, stroke, convulsions, or trauma. Some must be administered before the event, but others may be effective for some time after. They act by a variety of mechanisms, but often directly or indirectly minimize the damage produced by endogenous excitatory amino acids.

Drugs used to specifically facilitate learning or memory, particularly to prevent the cognitive deficits associated with dementias. These drugs act by a variety of mechanisms.

Piracetam displays a linear and time-dependent pharmacokinetic properties with low intersubject variability over a large range of doses. Piracetam is rapidly and extensively absorbed following oral administration with the peak plasma concentration is reached within 1 hour after dosing in fasted subjects. Following a single oral dose of 3.2 g piracetam, the peak plasma concentration (Cmax) was 84 µg/mL. Intake of food may decrease the Cmax by 17% and increase the time to reach Cmax (Tmax) from 1 to 1.5 hours. Tmax in the cerebrospinal fluid is achieved approximately 5 hours post-administration. The absolute bioavailability of piracetam oral formulations is close to 100% and the steady state plasma concentrations are achieved within 3 days of dosing.

Piracetam is predominantly excreted via renal elimination, where about 80-100% of the total dose is recovered in the urine. Approximately 90% of the dose of piracetam is excreted in the urine as unchanged drug.

Vd is approximately 0.6L/kg. Piracetam may cross the blood-brain barrier as it was measured in the cerebrospinal fluid following intravenous administration. Piracetam diffuses to all tissues except adipose tissues, crosses placental barrier and penetrates the membranes of isolated red blood cells.

The apparent total body clearance is 80-90 mL/min.

Piracetam is rapidly and almost completely absorbed. Peak plasma levels are reached within 1.5 hours after administration. The extent of oral bioavailability, assessed from the Area Under Curve (AUC), is close to 100% for capsules, tablets and solution.

Peak levels and AUC are proportional to the dose given. The volume of distribution of piracetam is 0.7 L/kg, and ... Clearance of the compound is dependent on the renal creatinine clearance and would be expected to diminish with renal insufficiency.