Betaloc Zok Special Precautions

Intravenous administration of calcium antagonists of the verapamil-type should not be given to patients treated with β-blockers.
Generally when treating patients with asthma, concomitant therapy with a β2-agonist (tablet and/or inhalation) should be administered. The dosage of β2-agonists may require adjustment (increase) when treatment with metoprolol CR/ZOK is started. The risk of metoprolol CR/ZOK interfering with β2-receptors is however less than with conventional tablet formulations of β1-selective blockers.
During treatment with metoprolol CR/ZOK, the risk of interfering with carbohydrate metabolism or masking hypoglycaemia is likely to be less than during treatment with conventional tablet formulations of β1-selective blockers and much less than with non-selective β-blockers.
Very rarely, a pre-existing A-V conduction disorder of moderate degree may become aggravated (possibly leading to A-V block).
If the patients develop increasing bradycardia, metoprolol CR/ZOK should be given in lower doses or gradually withdrawn.
Metoprolol CR/ZOK may aggravate the symptoms of peripheral arterial circulatory disorders.
Where metoprolol CR/ZOK is prescribed for a patient known to be suffering from a phaeochromocytoma, an alpha-blocker should be given concomitantly.
Abrupt withdrawal of β-blockade is hazardous especially in high risk patients, and should therefore not be done.
If there is a need to discontinue treatment with metoprolol CR/ZOK, this should preferably be done gradually over at least two weeks when the dose is reduced by half in each step down to the final step when a whole 25 mg tablet is reduced to a half tablet.
The final dose should be taken for at least four days before discontinuation. If symptoms occur, a slower withdrawal rate is recommended. Sudden withdrawal of β-blockade may aggravate chronic heart failure and also increase the risk of myocardial infarction and sudden death.
Prior to surgery the anaesthetist should be informed that the patient is receiving metoprolol CR/ZOK. It is not recommended to stop β-blocker treatment in patients undergoing surgery. Acute initiation of high-dose metoprolol to patients undergoing non-cardiac surgery should be avoided, since it has been associated with bradycardia, hypotension and stroke including fatal outcome in patients with cardiovascular risk factors.
In patients taking β-blockers anaphylactic shock assumes a more severe form and may be resistant to usual doses of adrenaline. Whenever possible, β-blockers should be avoided in patients who are at increased risk of anaphylaxis.
Effect on ability to drive and use machines: As dizziness and fatigue may occur in Betaloc ZOK treatment, this should be considered when strict attention is required, e.g. when driving or operating machines.