metoprolol tartrate
CLINICAL USE
Beta-adrenoceptor blocker:Hypertension Angina Cardiac arrhythmias Migraine prophylaxis Hyperthyroidism
DOSE IN NORMAL RENAL FUNCTION
Oral:Hypertension: 100–400 mg daily in divided dosesAngina: 50–100 mg 2–3 times daily Arrhythmias: 100–300 mg in 2–3 divided dosesMigraine: 100–200 mg daily in divided dosesHyperthyroidism: 50 mg 4 times daily IV: 5 mg repeated after 5 minutes to a total dose of 15 mgIn surgery: 2–4 mg by slow IV injection then 2 mg as required to a maximum of 10 mg
PHARMACOKINETICS
Molecular weight :684.8 %Protein binding :10–12 %Excreted unchanged in urine : 5–10 Volume of distribution (L/kg) :5.6half-life – normal/ESRD (hrs) :1–9 (av: 3.5)/Unchanged DOSE IN RENAL IMPAIRMENT
GFR (mL/MIN)
20 to 50 : Dose as in normal renal function 10 to 20 : Start with small doses and titrate in accordance with response <10 : Start with small doses and titrate in accordance with response DOSE IN PATIENTS UNDERGOING RENAL REPLACEMENT THERAPIES
CAPD :Not dialysed. Dose as in GFR <10 mL/min HD :Not dialysed. Dose as in GFR <10 mL/minHDF/high flux :Dialysed. Dose as in GFR <10 : mL/minCAV/VVHD :Probably dialysed. Dose as in GFR 10 to 20 mL/min IMPORTANT DRUG INTERACTIONS
Potentially hazardous interactions with other drugs Anaesthetics: enhanced hypotensive effect Analgesics: NSAIDs antagonise hypotensive effectAnti-arrhythmics: increased risk of myocardial depression and bradycardia; increased risk of bradycardia, myocardial depression and AV block with amiodarone; concentration increased by propafenoneAntibacterials: concentration reduced by rifampicinAntidepressants: enhanced hypotensive effect with MAOIs; concentration increased by citalopram and escitalopram and possibly by paroxetineAntihypertensives; enhanced hypotensive effect; increased risk of withdrawal hypertension with clonidine; increased risk of first dose hypotensive effect with post-synaptic alpha-blockers such as prazosinAntimalarials: increased risk of bradycardia with mefloquine; avoid with artemether/lumefantrineAntipsychotics enhanced hypotensive effect with phenothiazines Calcium-channel blockers: increased risk of bradycardia and AV block with diltiazem; hypotension and heart failure possible with nifedipine and nisoldipine; asystole, severe hypotension and heart failure with verapamil Diuretics: enhanced hypotensive effect Moxisylyte: possible severe postural hypotensionSympathomimetics: severe hypertension with adrenaline and noradrenaline and possibly with dobutamineMetoprolol tartrate.476 METoProLoL TArTrATETropisetron: increased risk of ventricular arrhythmias – use with caution ADMINISTRATION
Reconstition
– Route
Oral, IV Rate of Administration
For bolus injection, 1–2 mg/minute or by continuous infusion via CRIPComments
A total dose of 10–15 mg IV is usually sufficient OTHER INFORMATION
Can cause hypoglycaemia in dialysis patientsAlmost all the drug is excreted as inactive metabolites. Accumulation of the metabolites will occur in renal failure, but does not seem to cause any side effects.
See how to identify renal failure stages according to GFR calculation
See how to diagnose irreversible renal disease
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