When patients become cyanotic: acquired methemoglobinemia.

BACKGROUND: The authors conducted literature review to create a heightened awareness of the potential for developing toxic methemoglobinemia from local anesthetics. Methemoglobin normally is present in the blood at levels less than 1 percent. Levels may become toxic as hemoglobin is oxidized to methemoglobin after local anesthetics such as benzocaine and prilocaine are administered. TYPES OF STUDIES REVIEWED: The authors searched the medical and pharmaceutical industry literature. They found and reviewed case studies of incidences of methemoglobinemia that resulted from local anesthetic overdoses. RESULTS: Cases of local anesthetic-induced methemoglobinemia in dental practice are under-recognized and rare. Reported cases of prilocaine-induced methemoglobinemia have resulted in recent changes in some prilocaine literature. These changes include maximum recommended doses for patients of various weights. CLINICAL IMPLICATIONS: Dentists should identify patients who are at increased risk of developing methemoglobinemia before administering local anesthetics. They also should follow new recommended dosing guidelines for prilocaine and be aware of symptoms of this adverse reaction.

[Homicide simulating electrocution suicide by spinal anesthesia]. / Als Stromselbstmord vorgetäuschte Tötung durch Spinalanästhesie.

A married woman was found dead with indications of suicide by electricity (household-voltage). On coroner's inquest (typical electric lesions at the wrist) and the result of police investigation, there was no indication of third party involvement. The cadaver war firstly released to burial, but on account of indication of conflicts between the married couple, a forensic autopsy was arranged. The most important pathological finding was a fresh puncture between L3/L4. On toxicological investigation, toxic concentrations of the local anaesthetic prilocaine were found in liquor and organs. Cause of death was central respiratory- and circulatory depression. The husband, an anaesthesist, blamed he was assisting the suicide of his wife at her request. He was found guilty by reasons of manslaughter but not for murder.

Formation of formaldehyde adducts from various drugs by use of methanol in a toxicological screening procedure with gas chromatography-mass spectrometry.

Use of methanol as a solvent in a toxicological screening procedure with gas chromatography-mass spectrometry may be associated with artifact formation. Artifacts with a molecular ion of [M + 12]+ are formed from various drugs, such as amphetamine, propafenone, flecainide, beta-blockers and prilocaine. The mechanism of artifact formation was studied by mass spectral techniques, labelling and nuclear magnetic resonance spectroscopy. It was shown that the artifacts were generated by the addition of formaldehyde and subsequent loss of water. Formaldehyde is probably formed by thermal dehydrogenation of methanol in the injection port of the gas chromatograph.

Distribution of prilocaine in body fluids and tissues in lethal overdose.

A case of lethal overdose by prilocaine, a local anaesthetic, is presented. The patient died in the dental office during treatment, and the time course of events was documented. The drug concentration in blood, urine, and liver was measured.