Abstract
Dear Editor:
Relief from physical symptoms, including pain, is one of the most important issues in the management of cancer patients. Opioids are the primary drugs, 1 but they may show reduced or no effectiveness in some cases, necessitating the addition of another drug.
Lidocaine (a sodium channel blocker) is one of the most widely used local anaesthetics. The drug is thought to have a multifactorial action mechanism. Systemic administration of lidocaine has been shown to be effective in treating a variety of disorders that may involve neuropathic mechanisms, including seizures, chronic pain, and arrhythmias.
Although most of the studies for cancer patients on lidocaine have dealt with its role in the management of neuropathic pain, 2 some reports have described its effectiveness in treating other types of symptoms as well, including intractable cough. 3 While morphine is effective against cough, it may be ineffective against refractory cough; moreover, there are few alternatives for morphine in such cases. Since lidocaine and morphine have different mechanisms of action, a combination of these drugs may have a high potential for providing relief from symptoms.
Another point to consider is the effect of lidocaine on hiccups. 4 Although anticonvulsants are used to alleviate hiccups, the adverse effects of anticonvulsants, such as sedation and extrapyramidal symptoms, often necessitate discontinuation of medication. However, in most cases a lidocaine dose of 1 mg/kg – 5 mg/kg can be intravenously administered to patients without any severe adverse effects. 2
In addition, lidocaine offers the advantage of multiple administration routes (intravenous, subcutaneous, and patch) for a relatively lower cost, which is especially useful for advanced cancer patients who cannot take oral medications.
The mechanism underlying the beneficial effects of lidocaine on these symptoms is not completely understood; the symptoms may be alleviated by suppression of the hyperactivity of the nervous system and due to its membrane-stabilizing effect. 5 Since both severe cough and hiccup occur as a result of excessive stimulation of the reflex pathways, lidocaine may have beneficial effects on both symptoms. This also suggests that lidocaine may alleviate other symptoms induced by similar neural hyperexcitability mechanisms, e.g., irritable bladder syndrome.
Severe physical symptoms such as neuropathic pain, hiccups, and cough often cause a lot of distress to cancer patients. Systemic administration of lidocaine has significant potential to alleviate various symptoms.