Patients with MG and cancer considering cancer immunotherapy should talk to their oncologist and neurologist about this possible side effect. Major Potential Hazard, Moderate plausibility. Combination therapy with a diuretic or vasodilator may also be considered to further reduce blood pressure.Metoprolol may be administered with benefit both to previously untreated patients with hypertension and to those in whom the response to previous therapy is inadequate. • Cocaine may inhibit the therapeutic effects of beta-blockers and increase the risk of hypertension, excessive bradycardia, and possibly heart block. However, there is an increased risk of cardiac and pulmonary complications in the neonate in the postnatal period.
Although the drug crosses the placental barrier and is present in cord blood no evidence of foetal abnormalities has been reported. • The administration of adrenaline (epinephrine) or noradrenaline (norepinephrine) to patients undergoing beta-blockade can result in an increase in blood pressure and bradycardia, although this is less likely to occur with beta In addition, hypertension and arrhythmias may develop. It may be necessary to use a lower strength formulation in elderly patients and patients with hepatic or renal impairment and an alternative product should be prescribed.Patients with anamnestically known psoriasis should take beta-blockers only after careful consideration as the medicine may cause aggravation of psoriasis.Beta-blockers may increase both the sensitivity towards allergens and the seriousness of anaphylactic reactions. They should also consider, when appropriate, the pros and cons of an alternate treatment, if available.It is important that the patient notify his or her physicians if the symptoms of MG worsen after starting any new medication. Administration of calcium ions, or the use of a cardiac pacemaker may also be considered. • The effect of adrenaline (epinephrine) in the treatment of anaphylactic reactions may be weakened in patients receiving beta blockers (see also section 4.4). By shielding the heart against the effect of stress, metoprolol may prevent excessive sympathetic stimulation which is liable to provoke such cardiac disturbance as arrhythmias or acute coronary insufficiency during induction and intubation. Beta-blockers may unmask myasthenia gravis. In refractory cases isoprenaline can be combined with dopamine. The initial oral dose should not exceed 50mg twice daily.In order to achieve optimal benefits from intravenous metoprolol, suitable patients should present within 12 hours of the onset of chest pain. If possible, withdrawal of metoprolol should be completed at least 48 hours before anaesthesia. People who did not have MG before beginning immunotherapy have a higher likelihood of developing the disease , although worsening of myasthenic weakness has been reported in people with existing, previously-diagnosed MG. If this does not produce the desired effect either, intravenous administration of 8-10mg glucagon may be considered. It most commonly impacts young adult women (under 40) and older men (over 60), but it can occur at any age, including childhood. • The effects of metoprolol and other antihypertensive drugs on blood pressure are usually additive, and care should be taken to avoid hypotension. Physiol Rep. 2015;3(12):e12658. Beta-blockers used in conjunction with clonidine increase the risk of “rebound hypertension”. from Continuum 2009 1. May worsen or precipitate MG. Use with caution.