Lidocaine is also known as lignocaine/xylocaine, which an amide group commonly used local anesthetic drug. It is also used in some instances as spinal anesthesia and as an anti-arrhythmic drug.
Can Lidocaine Cause Malignant Hyperthermia?
Does lidocaine causes malignant hyperthermia? According to the Malignant Hyperthermia Association in the United States all local anesthetic drugs are safe. Lidocaine is also considers as a safe drug for malignant hyperthermia (MH) patients.
There are two types of local anesthetics ester type (Chloroprocaine, Procaine) and amide type (lidocaine, prilocaine, bupivacaine, mepivacaine). Earlier days in 1990’s studies done on ester local anesthetics revealed it reduces calcium release from the skeletal muscle sarcoplasmic reticulum. When ester local anesthetic is injected directly to the myotonic muscle it relieves the myotonia. However, in vitro experiments with lidocaine revealed that it causes muscle contractures therefore; it was contradicted to use lidocaine in patients with malignant hyperthermia (MH) as it can trigger malignant hyperthermia. After sometime they realized that the in vitro studies used very high concentrations of lidocaine, which can cause muscle contractures even in a normal muscle.
Then, there were studies done on animals which revealed lidocaine does not trigger malignant hyperthermia. Studies with mepivacaine showed that the malignant hyperthermia muscles are sensitive to the contracture-forming nature of mepivacaine. But a higher concentration of mepivacaine is needed to induce muscle contractures and such levels of concentration is not used in clinical practice of administering mepivacaine. Studies done in malignant hyperthermia patients with prilocaine, which causes more cardiac and neurological side effects, with a longer metabolism period, showed during the metabolism it converts hemoglobin to methemoglobinemia. But none of the patients got malignant hyperthermia triggered by prilocaine.
A case report was published in 1992 with a case of 72 years old male getting malignant hyperthermia after lidocaine injection and continuous infusion for an arrhythmia treatment. Patient’s temperature was 41.7℃, there was general muscle contractures and increased levels of serum and urine myoglobin. The patients was given large doses of lidocaine. Dantrolene sodium was given and it reduced the fever then lidocaine infusion was stopped. In this case malignant hyperthermia must have been triggered because of the high intravenous lidocaine dose. Higher blood concentration are achieved with intravenous local anesthesia than the other routes.
Therefore, lidocaine is quite safe to use as a local anesthetic agent with normal therapeutic doses in malignant hyperthermia patients.
The local anesthesia only works on a particular part of the body; it blocks pain signals from nerves in a particular area. You feel pain when the pain receptors which are at the end of nerves get stimulated and this causes sodium to enter into the nerve ending. Then, an electric signal builds up in the nerve and it travels to the brain, the brain interpret this results as pain. Then you feel the pain in that area. Lidocaine acts on the site of pain by stopping the sodium ions entering the nerve ending. This causes numbness in the area that lidocaine was injected.
There are many lidocaine concentrated solutions used for different types of surgery. Usually 0.5% and 1% lidocaine is used as local anesthesia. The maximum dose of with the above concentrations is 4 mg/kg. The target is to get the maximum effect from the smallest possible dose.
Summary
Lidocaine is also known as lignocaine/xylocaine, which an amide group commonly used local anesthetic drug. It’s also used in some instances as spinal anesthesia and as an anti-arrhythmic drug. There are many lidocaine concentrated solutions used for different types of surgery. Usually 0.5% and 1% lidocaine is used as local anesthesia. The maximum dose of with the above concentrations is 4mg/kg. According to the Malignant Hyperthermia Association in the United States all local anesthetic drugs are safe. Lidocaine is also considers as a safe drug for malignant hyperthermia (MH) patients. Earlier in vitro studies revealed that amide local anesthetics (lidocaine, prilocaine, bupivacaine, mepivacaine) triggered malignant hyperthermia, but later it revealed that was with high doses of amide anesthetics; also when high doses are given intravenously it can trigger malignant hyperthermia. Therefore, normal therapeutic doses of lidocaine are safe to use in as local anesthesia in malignant hyperthermia patients.
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