Mexiletine
Mexiletine. Class IB antiarrhythmic — voltage-gated Na+ channel blocker preferentially binding the inactivated state. Used for ventricular… Oral half-life 6.3 h.
Class IB antiarrhythmic — voltage-gated Na+ channel blocker preferentially binding the inactivated state. Used for ventricular arrhythmias + neuropathic pain (off-label) + myotonic syndromes. CYP2D6 substrate.
PK: ka 1.5 IS A TIME TO PEAK — "The corresponding peak times were 4.68 +/- 2.04 h and 1.46 +/- 0.17 h" — so the stored value is wrong by about a factor of two AND carries the wrong units. It is replaced by a genuine published population value of 3.1 /h. V 400 L was the MIDPOINT of an APPARENT range, 5.0 to 6.6 L/kg, taken from a review filed under FLECAINIDE references rather than this record — two defects compounding, a midpoint and an apparent volume paired with an independent bioavailability. Re-sourced to one study that restricted its analysis to the intravenous data, giving a true volume of 5.5 L/kg, a half-life of 6.34 h and a bioavailability of 87.3%. THE STORED 17 h WAS THE PRE-TREATMENT CONTROL ARM OF A PHENYTOIN INDUCTION STUDY and is an outlier against 6.34, 9-11, 10, 11.3 and 11.75 h elsewhere. TRAP LOGGED: the paper supplying the absorption rate also reports a 5.3 L/kg volume that is apparent; take the rate, never that volume. Absorption is measurably slowed by acute myocardial infarction.
Pharmacokinetics
- Oral — t½ 6.3 h · F 87% · ka 3.1 h⁻¹ · Vd 385 L
Sources: PMID:6662176, PMID:7226704, PMID:7151850