Source: Medicines and Medical Devices Safety Authority (NZ) Revision Year: 2020 Publisher: Novartis New Zealand Limited, PO Box 99102, Newmarket, Auckland 1149, Telephone: 0800 354 335
Disturbances of cardiac rhythm, including supraventricular and ventricular arrhythmias.
Hypertension: as monotherapy or for use in combination with other antihypertensives, for example, a diuretic, peripheral vasodilator or angiotensin converting-enzyme (ACE) inhibitor.
Angina pectoris: For long-term prophylaxis. Nitroglycerin should be used, if necessary, for alleviating acute attacks.
Hyperthyroidism (as adjunctive medication).
Functional heart disorders with palpitation.
Prevention of migraine.
Parenteral administration of Lopresor should be supervised by experienced staff in a setting in which monitoring and resuscitating equipment are available. For oral treatment, the tablets should be swallowed unchewed.
The dosage should be adapted to the requirements of the individual patient. The following dosage recommendations may be taken as a guide:
Ampoules: The starting dose is 5 mg, injected slowly intravenously (1 to 2 mg/min). The injection can be repeated at 5-minute intervals until a satisfactory clinical response has been obtained. A total dose of 10 to 15 mg generally proves sufficient; increasing the dose to 20 mg or more does not usually yield better results. “Use immediately after opening. Discard any unused portion”.
Tablets: The daily dose is 100 to 150 mg, given in 2 or 3 divided doses; if necessary, the daily dose can be increased to 300 mg.
The daily oral dose is 100 to 200 mg, given either as a single dose in the morning or as 2 divided doses (morning and evening). If necessary, another antihypertensive can be prescribed in addition (see Section 4.5 Interaction with other medicines and other forms of interaction).
Divitabs (fractionable sustained-release tablets): 1 of the Divitabs early in the morning. If necessary, another antihypertensive can be prescribed in addition. In mild hypertension, ½ of one of the Divitabs taken early in the morning may suffice.
The daily oral dose is 100 to 200 mg, given in 2 divided doses; if necessary, the daily dose can be increased to 400 mg.
Divitabs: ½ or 1 of the Divitabs early in the morning; if necessary, this dose can be repeated in the evening.
The daily oral dose is 150 to 200 mg (may be increased up to 400 mg), given in 3 or 4 divided doses.
The daily oral dose is 100 mg, given as a single dose in the morning; if necessary, the daily dose can be increased to 200 mg, given in 2 divided doses (morning and evening).
Divitabs: ½ of one of the Divitabs daily, given in the morning; if necessary, the daily dosage can be raised to 1 of the Divitabs, to be taken also as a single dose in the morning.
The daily oral dose is 100 mg, given as a single dose in the morning; if necessary, the daily dose can be increased to 200 mg, given in 2 divided doses (morning and evening)
Divitabs: ½ of one of the Divitabs daily, given in the morning; if necessary, the daily dosage can be raised to 1 of the Divitabs, to be taken also as a single dose in the morning.
No studies have been performed in paediatric patients. The safety and efficacy of Lopresor and Slow Lopresor in paediatric patients have not been established.
Lopresor blood levels are likely to increase substantially in patients with hepatic impairment. Therefore, Lopresor or Slow Lopresor should be initiated at low doses with cautious gradual dose titration according to clinical response.
No dose adjustment of Lopresor or Slow Lopresor is required in geriatric patients but it should be given with caution due to increased likelihood of adverse events.
An overdosage of Lopresor or Slow Lopresor may lead to severe hypotension, sinus bradycardia, atrioventricular block, myocardial infarction, heart failure, cardiogenic shock, cardiac arrest, bronchospasm, impairment of consciousness (or even coma), convulsions, nausea, vomiting, and cyanosis and death.
Concomitant ingestion of alcohol, antihypertensives, quinidine, or barbiturates aggravates the signs and symptoms.
The first manifestations of overdose appear 20 minutes to 2 hours after ingestion of Lopresor or Slow Lopresor. The effects of massive overdose may persist for several days, despite declining plasma concentrations.
Patients should be admitted to hospital and, generally, should be managed in an intensive care setting, with continuous monitoring of cardiac function, blood gases, and blood biochemistry. Emergency supportive measures such as artificial ventilation or cardiac pacing should be instituted if appropriate. Even apparently well patients who have taken a small overdose should be closely observed for signs of poisoning for at least 4 hours.
In the event of a potentially life-threatening oral overdose, use induction of vomiting or gastric lavage (if within 4 hours after ingestion of Lopresor or Slow Lopresor) and/or activated charcoal to remove the drug from the gastrointestinal tract. Haemodialysis is unlikely to make a useful contribution to metoprolol elimination.
Atropine may be given intravenously to control significant bradycardia. Intravenous beta-agonists such as prenalterol or isoprenaline should be used to treat bradycardia and hypotension; very high doses may be needed to overcome the beta-blockade. Dopamine, dobutamine or noradrenaline may be given to maintain blood pressure. Glucagon has positive inotropic and chronotropic effects on the heart that are independent of beta-adrenergic receptors, and has proved effective in the treatment of resistant hypotension and heart failure associated with beta-blocker overdose.
Diazepam is the drug of choice for controlling seizures. A beta -agonist or aminophylline can be used to reverse bronchospasm; patients should be monitored for evidence of cardiac arrhythmias during and after administration of the bronchodilator.
The beta-blocker withdrawal phenomenon (see Section 4.4 Special warnings and precautions for use) may occur after overdose.
For advice on the management of overdose please contact the National Poisons Centre 0800 POISON (0800 764766).
Ampoules: 5 years.
Tablets of 50 mg and 100 mg: 3 years.
Slow Lopresor of 200 mg: 5 years.
Ampoules: Protect from light. Store at or below 25°C.
Tablets 50 mg: Protect from moisture and heat (store below 30°C).
Tablets 100 mg: Protect from moisture (store below 30°C).
Slow Lopresor 200mg: Special storage requirements.
Lopresor and Slow Lopresor should be kept out of the reach and sight of children.
Lopresor 50mg: bottles containing 100 tablets.
Lopresor 100mg: bottles containing 60 tablets.
Slow Lopresor 200mg: blisters containing 28 tablets.
Not all pack sizes may be marketed.
There are no specific instructions for use/handling.
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