ADVERSE REACTIONS
MEXITIL (mexiletine hydrochloride, USP) commonly produces reversible gastrointestinal and nervous system adverse reactions but is otherwise well tolerated. MEXITIL has been evaluated in 483 patients in one-month and three-month controlled studies and in over 10,000 patients in a large compassionate use program. Dosages in the controlled studies ranged from 600-1200 mg/day; some patients (8%) in the compassionate use program were treated with higher daily doses (1600-3200 mg/day). In the three-month controlled trials comparing MEXITIL to quinidine, procainamide and disopyramide, the most frequent adverse reactions were upper gastrointestinal distress (41%), lightheadedness (10.5%), tremor (12.6%) and coordination difficulties (10.2%). Similar frequency and incidence were observed in the one-month placebo-controlled trial. Although these reactions were generally not serious, and were dose-related and reversible with a reduction in dosage, by taking the drug with food or antacid or by therapy discontinuation, they led to therapy discontinuation in 40% of patients in the controlled trials. Table 1 presents the adverse events reported in the one-month placebo-controlled trial.
Table 1: Comparative Incidence (%) of Adverse Events Among Patients Treated with Mexiletine and Placebo in the 4- Week, Double-blind Crossover Trial | Mexiletine N=53 | Placebo N=49 |
Cardiovascular | | |
Palpitations | 7.5 | 10.2 |
Chest Pain | 7.5 | 4.1 |
Increased Ventricular Arrhythmia /PVC's | 1.9 | - |
Digestive | | |
Nausea/Vomiting/Heartburn | 39.6 | 6.1 |
Central Nervous System | | |
Dizziness/ Lightheadedness | 26.4 | 14.3 |
Tremor | 13.2 | — |
Nervousness | 11.3 | 6.1 |
Coordination Difficulties | 9.4 | — |
Changes in Sleep Habits | 7.5 | 16.3 |
Paresthesias/Numbness | 3.8 | 2.0 |
Weakness | 1.9 | 4.1 |
Fatigue | 1.9 | 2.0 |
Tinnitus | 1.9 | 4.1 |
Confusion/Clouded Sensorium | 1.9 | 2.0 |
Other | | |
Headache | 7.5 | 6.1 |
Blurred Vision/Visual Disturbances | 7.5 | 2.0 |
Dyspnea/Respiratory | 5.7 | 10.2 |
Rash | 3.8 | 2.0 |
Non-specific Edema | 3.8 | — |
Table 2 presents the adverse reactions occurring in one percent or more of patients in the three-month controlled studies.
Table 2: Comparative Incidence (%) of Adverse Events Among Patients Treated with Mexiletine or Control Drugs in the 12-Week Double-blind Trials | Mexiletine | Quinidine | Procainamide | Disopyramide |
| N = 430 | N = 262 | N = 78 | N = 69 |
Cardiovascular | | | | |
Palpitations | 4.3 | 4.6 | 1.3 | 5.8 |
Chest Pain | 2.6 | 3.4 | 1.3 | 2.9 |
Angina/Angina- like Pain | 1.7 | 1.9 | 2.6 | 2.9 |
Increased Ventricular Arrhythmias/PVC's | 1.0 | 2.7 | 2.6 | — |
Digestive | | | | |
Nausea/Vomiting/Heartburn | 39.3 | 21.4 | 33.3 | 14.5 |
Diarrhea | 5.2 | 33.2 | 2.6 | 8.7 |
Constipation | 4.0 | — | 6.4 | 11.6 |
Changes in Appetite | 2.6 | 1.9 | — | — |
Abdominal Pain/Cramps/Discomfort | 1.2 | 1.5 | — | 1.4 |
Central Nervous System | | | | |
Dizziness/Lightheadedness | 18.9 | 14.1 | 14.1 | 2.9 |
Tremor | 13.2 | 2.3 | 3.8 | 1.4 |
Coordination Difficulties | 9.7 | 1.1 | 1.3 | — |
Changes in Sleep Habits | 7.1 | 2.7 | 11.5 | 8.7 |
Weakness | 5.0 | 5.3 | 7.7 | 2.9 |
Nervousness | 5.0 | 1.9 | 6.4 | 5.8 |
Fatigue | 3.8 | 5.7 | 5.1 | 1.4 |
Speech Difficulties | 2.6 | 0.4 | — | — |
Confusion/Clouded Sensorium | 2.6 | — | 3.8 | — |
Paresthesias/Numbness | 2.4 | 2.3 | 2.6 | — |
Tinnitus | 2.4 | 1.5 | — | — |
Depression | 2.4 | 1.1 | 1.3 | 1.4 |
Other | | | | |
Blurred Vision/Visual Disturbances | 5.7 | 3.1 | 5.1 | 7.2 |
Headache | 5.7 | 6.9 | 7.7 | 4.3 |
Rash | 4.2 | 3.8 | 10.3 | 1.4 |
Dyspnea/ Respiratory | 3.3 | 3.1 | 5.1 | 2.9 |
Dry Mouth | 2.8 | 1.9 | 5.1 | 14.5 |
Arthralgia | 1.7 | 2.3 | 5.1 | 1.4 |
Fever | 1.2 | 3.1 | 2.6 | — |
Less than 1%: Syncope, edema, hot flashes, hypertension, short-term memory loss, loss of consciousness, other psychological changes, diaphoresis, urinary hesitancy/retention, malaise, impotence/decreased libido, pharyngitis, congestive heart failure.
An additional group of over 10,000 patients has been treated in a program allowing administration of MEXITIL (mexiletine hydrochloride, USP) under compassionate use circumstances. These patients were seriously ill with the large majority on multiple drug therapy. Twenty-four percent of the patients continued in the program for one year or longer. Adverse reactions leading to therapy discontinuation occurred in 15 percent of patients (usually upper gastrointestinal system or nervous system effects). In general, the more common adverse reactions were similar to those in the controlled trials. Less common adverse events possibly related to MEXITIL use include:
Cardiovascular System: Syncope and hypotension, each about 6 in 1000; bradycardia, about 4 in 1000; angina/angina-like pain, about 3 in 1000; edema, atrioventricular block/conduction disturbances and hot flashes, each about 2 in 1000; atrial arrhythmias, hypertension and cardiogenic shock, each about 1 in 1000.
Central Nervous System: Short-term memory loss, about 9 in 1000 patients; hallucinations and other psychological changes, each about 3 in 1000; psychosis and convulsions/seizures, each about 2 in 1000; loss of consciousness, about 6 in 10,000.
Digestive: Dysphagia, about 2 in 1000; peptic ulcer, about 8 in 10,000; upper gastrointestinal bleeding, about 7 in 10,000; esophageal ulceration, about 1 in 10,000. Rare cases of severe hepatitis/acute hepatic necrosis.
Skin: Rare cases of exfoliative dermatitis and Stevens-Johnson Syndrome with MEXITIL (mexiletine hydrochloride, USP) treatment have been reported.
Laboratory: Abnormal liver function tests, about 5 in 1000 patients; positive ANA and thrombocytopenia, each about 2 in 1000; leukopenia (including neutropenia and agranulocytosis), about 1 in 1000; myelofibrosis, about 2 in 10,000 patients.
Other: Diaphoresis, about 6 in 1000; altered taste, about 5 in 1000; salivary changes, hair loss and impotence/decreased libido, each about 4 in 1000; malaise, about 3 in 1000; urinary hesitancy/retention, each about 2 in 1000; hiccups, dry skin, laryngeal and pharyngeal changes and changes in oral mucous membranes, each about 1 in 1000; SLE syndrome, about 4 in 10,000.
Hematology
Blood dyscrasias were not seen in the controlled trials but did occur among 10,867 patients treated with mexiletine in the compassionate use program (see PRECAUTIONS).
Myelofibrosis was reported in two patients in the compassionate use program: one was receiving long-term thiotepa therapy and the other had pretreatment myeloid abnormalities.
In post-marketing experience, there have been isolated, spontaneous reports of pulmonary changes including pulmonary infiltration and pulmonary fibrosis during MEXITIL therapy with or without other drugs or diseases that are known to produce pulmonary toxicity. A causal relationship to MEXITIL therapy has not been established. In addition, there have been isolated reports of drowsiness, nystagmus, ataxia, dyspepsia, hypersensitivity reaction, and exacerbation of congestive heart failure in patients with pre-existing compromised ventricular function. There have been rare reports of pancreatitis associated with MEXITIL treatment.
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REPORTS OF SUSPECTED MEXITIL SIDE EFFECTS / ADVERSE REACTIONS
Below is a sample of reports where side effects / adverse reactions may be related to Mexitil. The information is not vetted and should not be considered as verified clinical evidence.
Possible Mexitil side effects / adverse reactions in 60 year old male
Reported by a physician from Japan on 2011-07-15
Patient: 60 year old male weighing 89.0 kg (195.8 pounds)
Reactions: Back Pain, Blood Alkaline Phosphatase Increased, Blood Lactate Dehydrogenase Increased, Alanine Aminotransferase Increased, Liver Disorder, Pruritus Generalised, Malaise, Dyspnoea Exertional, Gamma-Glutamyltransferase Increased, Aspartate Aminotransferase Increased, Cold Sweat, Cough
Adverse event resulted in: hospitalization
Suspect drug(s):
Warfarin Sodium
Dosage: 4 mg (1 mg,4 in 1 d),oral
Administration route: Oral
Indication: Product Used FOR Unknown Indication
Start date: 2009-05-11
End date: 2011-05-31
Mexitil
Dosage: 50mg x 6t x 3 (50 mg),oral
Administration route: Oral
Indication: Product Used FOR Unknown Indication
Start date: 2009-05-11
End date: 2011-06-03
Amlodipine Besylate
Dosage: 5 mg (5 mg,1 in 1 d),oral
Administration route: Oral
Indication: Product Used FOR Unknown Indication
Start date: 2009-05-11
End date: 2011-06-03
Diovan
Dosage: 160 mg (80 mg,2 in 1 d),oral
Administration route: Oral
Indication: Product Used FOR Unknown Indication
Start date: 2009-05-11
End date: 2011-06-03
Bisoprolol Fumarate
Dosage: 5 mg (2.5 mg,2 in 1 d),oral
Administration route: Oral
Indication: Product Used FOR Unknown Indication
Start date: 2009-06-27
End date: 2011-06-03
Mecobalamine (Becobalamin)
Dosage: 550ug x 3t x 3 (500 mcg),oral
Administration route: Oral
Indication: Product Used FOR Unknown Indication
Start date: 2010-03-03
End date: 2011-06-03
Epinastine Hydrochloride (Aleroff)
Dosage: (20 mg,1 in 1 d),oral
Administration route: Oral
Indication: Product Used FOR Unknown Indication
Start date: 2011-04-14
End date: 2011-06-03
Doxazosin Mesylate
Dosage: 4 mg (2 mg,2 in 1 d),oral
Administration route: Oral
Indication: Product Used FOR Unknown Indication
Start date: 2009-07-15
End date: 2011-06-03
Lansoprazole
Dosage: 15 mg (15 mg,1 in 1 d),oral
Administration route: Oral
Indication: Product Used FOR Unknown Indication
Start date: 2009-05-11
End date: 2011-06-03
Pirmenol Hydrochloride/hydrate (Pimenol)
Dosage: 50mg x 2capsules x 2 (50 mg),oral
Administration route: Oral
Indication: Product Used FOR Unknown Indication
Start date: 2009-05-11
End date: 2011-06-03
Mosapride Citrate/hydrate (Gasmotin)
Dosage: 5mg x 3t x 3 (5 mg),oral
Administration route: Oral
Indication: Product Used FOR Unknown Indication
Start date: 2009-12-02
End date: 2011-06-03
Magnesium Oxide (Magmitt)
Dosage: 250mg x 3t x 3 (250 mg),oral
Administration route: Oral
Indication: Product Used FOR Unknown Indication
Start date: 2009-07-04
End date: 2011-05-31
Sairei-TO
Dosage: 8.1mg x 2t x 2 (8.1 mg),oral
Administration route: Oral
Indication: Product Used FOR Unknown Indication
Start date: 2010-08-05
End date: 2011-05-30
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