Cardivas (carvedilol) is contraindicated (not permitted to be used at all) in 2nd and 3rd degree heart blocks. With regard to Left Bundle Branch Block (LBBB), there can be many causes such as coronary artery disease, aortic valve disease, cardiomyopathy etc. Depending on the cause a decision has to be taken whether or not to use Cardivas and in what dose. Unless it is absolutely essential, in general its use should be avoided if there is any heart disorder.
In your fathers case Cardivas is apparently being given for high blood pressure. Recently based on global experience, the treatment of high blood pressure has undergone major changes. It has been established that betablockers such as Cardivas pose an unacceptable risk of precipitating diabetes and hence should not be used, particularly in the elderly. The globally accepted guidelines are:
In patients aged 55 and over, first choice of initial therapy should be either a calcium channel blocker (such as amlodipine sold under the trade name of Amlodac) or a diuretic such as metolazone (sold under the trade name of Metoz) mg daily in the morning. If a second drug is required, add an ACE inhibitor such as enalapril (sold as BQL) or ramipril (sold as Ramace etc). If an ACE inhibitor is not tolerated (some patients may get cough), an Angiotensin receptor blocker such as losartan (sold as Losacar) can be used.
For all patients (whether below or above 55 years of age) if treatment with three drugs is required, the combination of ACE inhibitor such as BQL or Ramace (or an Angiotensin receptor blocker such as Losacar if an ACE inhibitor is not tolerated), calcium channel blocker such as Amlodac and a diuretic such as Metoz should be used.
Beta-blockers (such as Cardivas) are not recommended because they perform less well than other drugs, particularly in the elderly, and the increasing evidence that they carry an unacceptable risk of provoking diabetes.