Details

Mexiletine affects the way that your heart beats. Mexiletine is used to treat seriously irregular heartbeats. You should not use mexiletine if you have a serious heart condition such as "AV block" (unless you have a pacemaker). Mexiletine may cause you to have abnormal liver function tests, especially if you also have congestive heart failure, or blood circulation problems. To make sure mexiletine is safe for you, tell your doctor if you have liver disease congestive heart failure epilepsy or other seizure disorder a weak immune system (caused by disease or by using certain medicine) or if you have recently taken other heart rhythm medicines.

Typical Uses

Mexiletine is used to treat certain types of serious (possibly fatal) irregular heartbeat (such as persistent ventricular tachycardia). It is used to restore normal heart rhythm and maintain a regular, steady heartbeat. Mexiletine is known as an anti-arrhythmic drug. It works by blocking certain electrical signals in the heart that can cause an irregular heartbeat. Treating an irregular heartbeat can decrease the risk for blood clots, and this effect can reduce your risk of heart attack or stroke. This drug may also be used to treat pain, numbness, and tingling from a certain nerve problem (peripheral neuropathy) which may occur in people with diabetes.

Side Effects

Common mexiletine side effects may include chest pain a new or a worsening irregular heartbeat pattern or liver problems, nausea, upper stomach pain, itching, tired feeling, loss of appetite, dark urine, clay-coloured stools, jaundice (yellowing of the skin or eyes).

Drug Interactions

• Mexiletine+tramadol- Tramadol may rarely cause seizures, and combining it with other medications that can also cause seizures such as mexiletine may increase that risk. The interaction may be more likely if you are elderly, undergoing alcohol or drug withdrawal, have a history of seizures, or have a condition affecting the central nervous system such as a brain tumour or head trauma.
• Mexiletine+bupropion- Bupropion may rarely cause seizures, and combining it with other medications that can also cause seizures such as mexiletine may increase that risk. The interaction may be more likely if you are elderly, undergoing alcohol or drug withdrawal, have a history of seizures, or have a condition affecting the central nervous system such as a brain tumour or head trauma.
• Mexiletine+droperidol- Using droperidol together with mexiletine can increase the risk of an irregular heart rhythm that may be serious and potentially life-threatening, although it is a relatively rare side effect. You may be more susceptible if you have a heart condition called congenital long QT syndrome, other cardiac diseases, conduction abnormalities, or electrolyte disturbances.
• Mexiletine+metrizamide- Before you undergo any imaging procedure where metrizamide may be injected directly into the spine let your doctor know if you are currently being treated with mexiletine. Injection of metrizamide into the spine can sometimes cause seizures, and the risk may be increased if you are also using other medications that can cause seizures such as mexiletine.

Mechanism of action

Mexiletine inhibits the inward sodium current required for the initiation and conduction of impulses, thus reducing the rate of rise of the action potential, Phase 0. It achieves this reduced sodium current by inhibiting sodium channels. Mexiletine decreases the effective refractory period (ERP) in Purkinje fibres in the heart. The decrease in ERP is of lesser magnitude than the decrease in action potential duration (APD), which results in an increase in the ERP/APD ratio. It does not significantly affect resting membrane potential or sinus node automaticity, left ventricular function, systolic arterial blood pressure, atrioventricular (AV) conduction velocity, or QRS or QT intervals.

Pregnancy Category : C