The factors that most influence metoprolol dosage are the condition and response of the patient. A person’s age also matters, and pediatric doses are based on weight. The form of the drug is another consideration because the intravenous solution is much stronger than oral tablets. Additionally, metoprolol dosage may change under certain circumstances, like an impending surgery or the use of additional medications or therapies.
Beta blockers like metoprolol treat hypertension or angina, or they could be recommended during the recovery period after a heart attack. This medication may also be indicated for adult congestive heart failure (CHF) or pediatric hypertension. Alternately, the drug may be used off-label for migraine prevention.
Irrespective of condition, doses typically start low and increase. A patient’s symptoms and response to the drug most determines the ultimate metoprolol dosage. The indications listed below are based on averages and maximum calculations, but they cannot account for how each patient will respond. In other words, it’s possible that two similar people will take very different amounts of the medication to treat the same condition.
For hypertension, adults begin with 100 milligrams (mg), ordinarily split into at least two doses. This amount might increase weekly to a maximum of 450 mg per day. Ordinarily the metoprolol is halved or quartered because even in extended release formulas, full-day coverage for hypertension may not be provided without more frequent ingestion of the medication. Adult angina has similar indications to hypertension, except that the maximum effective amount is considered to be 400 mg.
Metoprolol dosage for myocardial infarction (MI) is somewhat different. First, the drug may be used in an intravenous (IV) form directly after a heart attack, with injections of 5 mg every two minutes for 15 minutes. If a patient remains on the IV medication, doses could then range from 5 to 15 mg every six hours. Once an individual can tolerate oral doses, these are likely to be 50 mg each six hours.
When the metoprolol dosage is considered for congestive heart failure, it often requires a once a day, extended release formula that begins at 25 mg. As with MI, these doses may rise to 200 mg daily. The exact amount, though, depends on how well the drug is working to control symptoms. This is similarly the case with migraine prevention, which has a 200 mg daily maximum, too.
Pediatric metoprolol dosage for hypertension is initially calculated by applying the formula of 1 to 2 milligrams of the drug per kilogram (mg/kg) of weight. Extended release initial doses are 1 mg/kg. For children, the maintenance dose cannot exceed 200 mg a day.
There can be other changes to metoprolol dosage that are dependent on circumstances. Many doctors prefer to temporarily discontinue the medicine prior to surgeries. Additionally, co-administration of other medications, like anti-arrhythmic drugs, antihistamines, antidepressants and antifungals, needs to be carefully surveyed for interactions. Also, patients who have hemodialysis tend to require an extra dose of metoprolol with each procedure.
