METOLAR AM-25 Tablets
Each tablet contains:
Metoprolol succinate equivalent to tartrate.............. 25 mg
Amlodipine besylate............... 5 mg
METOLAR AM-50 Tablets
Each tablet contains:
Metoprolol succinate equivalent to tartrate............ 50 mg
Amlodipine besylate..............5 mg
METOLAR AM tablets are a fixed-dose combination of metoprolol extended-release, a selective beta1-adrenoceptor antagonist, and amlodipine, a dihydropyridine calcium channel blocker.
Metoprolol Extended-Release
Metoprolol is a beta1-selective (cardioselective) adrenergic receptor blocking agent. This preferential effect is not absolute, however, and at higher plasma concentrations, metoprolol also inhibits beta2-adrenoreceptors, chiefly located in the bronchial and vascular musculature. Metoprolol has no intrinsic sympathomimetic activity, and membrane-stabilizing activity is detectable only at plasma concentrations much greater than required for beta-blockade. Animal and human experiments indicate that metoprolol slows the sinus rate and decreases atrioventricular (AV) nodal conduction.
Clinical pharmacology studies have confirmed the beta-blocking activity of metoprolol in man, as shown by (1) reduction in the heart rate and cardiac output at rest and upon exercise, (2) reduction of systolic blood pressure upon exercise, (3) inhibition of isoproterenol-induced tachycardia, and (4) reduction of reflex orthostatic tachycardia.
The relative beta1-selectivity of metoprolol has been confirmed by the following: (1) In normal subjects, metoprolol is unable to reverse the beta2-mediated vasodilating effects of epinephrine. This contrasts with the effect of nonselective beta-blockers, which completely reverse the vasodilating effects of epinephrine. (2) In asthmatic patients, metoprolol reduces forced expiratory volume in the first second (FEV1) and forced vital capacity (FVC) significantly less than a nonselective beta-blocker, propranolol, at equivalent beta1-receptor blocking doses.
In clinical trials, metoprolol extended-release administered once a day, and immediate-release metoprolol administered once to four times a day, provided comparable total beta1-blockade over 24 hours (area under the beta1-blockade versus time curve) in the dose range 100-400 mg. At a dosage of 50 mg once daily, metoprolol extended-release produced significantly higher total beta1-blockade over 24 hours than immediate-release metoprolol. For metoprolol extended-release, the percent reduction in exercise heart rate was relatively stable throughout the entire dosage interval and the level of beta1-blockade increased with increasing doses from 50 to 300 mg daily. In contrast to metoprolol extended-release, immediate-release metoprolol given at a dose of 50-100 mg once a day produced a significantly larger peak effect on exercise tachycardia, but the effect was not evident at 24 hours. To match the peak to trough ratio obtained with metoprolol extended-release over the dosing range of 200 to 400 mg, a t.i.d. to q.i.d. divided dosing regimen was required for immediate-release metoprolol. A controlled cross-over study in heart failure patients compared the plasma concentrations and beta1-blocking effects of 50 mg immediate-release metoprolol administered t.i.d., 100 mg and 200 mg metoprolol extended-release once daily. A 50 mg dose of immediate-release metoprolol t.i.d. produced a peak plasma level of metoprolol similar to the peak level observed with 200 mg of metoprolol extended-release. A 200 mg dose of metoprolol extended-release produced a larger effect on suppression of exercise-induced and Holter-monitored heart rate over 24 hours compared to 50 mg t.i.d. of immediate-release metoprolol.
The relationship between plasma metoprolol levels and reduction in exercise heart rate is independent of the pharmaceutical formulation. Using an Emax model, the maximum effect is a 30% reduction in exercise heart rate, which is attributed to beta1-blockade. Beta1-blocking effects in the range of 30-80% of the maximal effect (approximately 8-23% reduction in exercise heart rate) correspond to metoprolol plasma concentrations from 30-540 nmol/L. The relative beta1-selectivity of metoprolol diminishes and blockade of beta2-adrenoceptors increases at plasma concentrations above 300 nmol/L.
Although beta-adrenergic receptor blockade is useful in the treatment of angina, hypertension, and heart failure there are situations in which sympathetic stimulation is vital. In patients with severely damaged hearts, adequate ventricular function may depend on sympathetic drive. In the presence of AV block, beta-blockade may prevent the necessary facilitating effect of sympathetic activity on conduction. Beta2-adrenergic blockade results in passive bronchial constriction by interfering with endogenous adrenergic bronchodilator activity in patients subject to bronchospasm and may also interfere with exogenous bronchodilators in such patients.
In other studies, treatment with metoprolol extended-release produced an improvement in left ventricular ejection fraction. Metoprolol extended-release was also shown to delay the increase in left ventricular end-systolic and end-diastolic volumes after 6 months of treatment.
Hypertension: The mechanism of the antihypertensive effects of beta-blocking agents has not been elucidated. However, several possible mechanisms have been proposed: (1) competitive antagonism of catecholamines at peripheral (especially cardiac) adrenergic neuron sites, leading to decreased cardiac output; (2) a central effect leading to reduced sympathetic outflow to the periphery; and (3) suppression of renin activity.
Angina Pectoris: By blocking catecholamine-induced increases in heart rate, in velocity and extent of myocardial contraction, and in blood pressure, metoprolol reduces the oxygen requirements of the heart at any given level of effort, thus making it useful in the long-term management of angina pectoris.
Amlodipine
Amlodipine is a dihydropyridine calcium antagonist (calcium ion antagonist or slow-channel blocker) that inhibits the transmembrane influx of calcium ions into vascular smooth muscle and cardiac muscle. The contractile processes of cardiac muscle and vascular smooth muscle are dependent upon the movement of extracellular calcium ions into these cells through specific ion channels. Amlodipine inhibits calcium ion influx across cell membranes selectively, with a greater effect on vascular smooth muscle cells than on cardiac muscle cells. Negative inotropic effects can be detected in vitro but such effects have not been seen in intact animals at therapeutic doses. Serum calcium concentration is not affected by amlodipine. Within thephysiologic pH range, amlodipine is an ionized compound (pKa=8.6), and its kinetic interaction with the calcium channel receptor is characterized by a gradual rate of association and dissociation with the receptor binding site, resulting in a gradual onset of effect.Amlodipine is a peripheral arterial vasodilator that acts directly on vascular smooth muscle to cause a reduction in peripheral vascular resistance and reduction in blood pressure.
The precise mechanisms by which amlodipine relieves angina have not been fully delineated, but are thought to include the following:
Exertional angina: In patients with exertional angina, amlodipine reduces the total peripheral resistance (afterload) against which the heart works and reduces the rate pressure product, and thus myocardial oxygen demand, at any given level of exercise.
Vasospastic angina: Amlodipine has been demonstrated to block constriction and restore blood flow in coronary arteries and arterioles in response to calcium, potassium epinephrine, serotonin, and thromboxane A2 analog in experimental animal models and in human coronary vessels in vitro. This inhibition of coronary spasm is responsible for the effectiveness of amlodipine in vasospastic (Prinzmetal's or variant) angina.
Hemodynamics
Following administration of therapeutic doses to patients with hypertension, amlodipine produces vasodilation, resulting in a reduction of supine and standing blood pressures. These decreases in blood pressures are not accompanied by a significant change in heart rate or plasma catecholamine levels with chronic dosing. Although the acute intravenous (IV) administration of amlodipine decreases arterial blood pressure and increases heart rate in hemodynamic studies of patients with chronic stable angina, chronic oral administration of amlodipine in clinical trials did not lead to clinically significant changes in the heart rate or blood pressures in normotensive patients with angina.
With chronic once daily oral administration, antihypertensive effectiveness is maintained for at least 24 hours. Plasma concentrations correlate with effect in both young and elderly patients. The magnitude of reduction in blood pressure with amlodipine is also correlated with the height of pretreatment elevation; thus, individuals with moderate hypertension (diastolic pressure 105-114 mmHg) had about a 50% greater response than patients with mild hypertension (diastolic pressure 90-104 mmHg). Normotensive subjects experienced no clinically significant change in blood pressures (+1/-2 mmHg).
In hypertensive patients with normal renal function, therapeutic doses of amlodipine resulted in a decrease in renal vascular resistance and an increase in the glomerular filtration rate and effective renal plasma flow, without a change in the filtration fraction or proteinuria.
As with other calcium channel blockers, hemodynamic measurements of cardiac function at rest and during exercise (or pacing) in patients with normal ventricular function treated with amlodipine have generally demonstrated a small increase in cardiac index without significant influence on dP/dt or on left ventricular end-diastolic pressure or volume. In hemodynamic studies, amlodipine has not been associated with a negative inotropic effect when administered in the therapeutic dose range to intact animals and man, even when co-administered with beta-blockers to man. Similar findings, however, have been observed in normal or well-compensated heart failure patients with agents possessing significant negative inotropic effects.
Electrophysiologic Effects
Amlodipine does not change sinoatrial nodal function or AV conduction in intact animals or man. In patients with chronic stable angina, IV administration of 10 mg did not significantly alter A-H and H-V conduction and sinus node recovery time after pacing. Similar results were obtained in patients receiving amlodipine and concomitant beta-blockers. In clinical studies in which amlodipine was administered in combination with beta-blockers to patients with either hypertension or angina, no adverse effects on electrocardiographic parameters were observed. In clinical trials with angina patients alone, amlodipine therapy did not alter electrocardiographic intervals or produce higher degrees of AV blocks.
Absorption
Metoprolol Extended-Release
Absorption of metoprolol is rapid and complete. Plasma levels following oral administration of conventional metoprolol tablets, however, approximate 50% of levels following IV administration, indicating about 50% first-pass metabolism. The plasma metoprolol levels following administration of metoprolol succinate extended-release are characterized by lower peaks, longer time to peak and significantly lower peak-to-trough variation. At steady state, the average bioavailability of metoprolol following administration of metoprolol succinate extended-release, across the dosage range of 50-400 mg once daily, was 77% relative to the corresponding single or divided doses of conventional metoprolol. The bioavailability of metoprolol shows a dose-related, although not directly proportional, increase with dose and is not significantly affected by food following metoprolol succinate extended-release administration.
Amlodipine
After oral administration of therapeutic doses of amlodipine, absorption produces peak plasma concentrations between 6-12 hours. Absolute bioavailability has been estimated to be between 64-90%. The bioavailability of amlodipine is not altered by the presence of food. Steady-state plasma levels of amlodipine are reached after 7-8 days of consecutive daily dosing.
Distribution
Metoprolol Extended-Release
Metoprolol crosses the blood brain barrier and has been reported in the cerebral spinal fluid (CSF) at a concentration measuring 78% of the simultaneous plasma concentration. Plasma levels achieved are highly variable after oral administration. Only a small fraction of the drug (about 12%) is bound to human serum albumin. In comparison to conventional metoprolol, the plasma metoprolol levels following administration of metoprolol extended-release are characterized by lower peaks, longer time to peak and significantly lower peak-to-trough variation. The peak plasma levels following once-daily administration of metoprolol extended-release average one-fourth to one-half the peak levels obtained following a corresponding dose of conventional metoprolol, administered once daily or in divided doses.
Amlodipine
Ex vivo studies have shown that approximately 93% of the circulating drug is bound to plasma proteins in hypertensive patients
Metabolism
Metoprolol Extended-Release
When administered orally, it exhibits a stereoselective metabolism that is dependent on oxidation phenotype.
Amlodipine
Amlodipine is extensively (about 90%) converted to inactive metabolites via hepatic metabolism.
Elimination
Metoprolol Extended-Release
Elimination is mainly by biotransformation in the liver, and the plasma half-life ranges from approximately 3-7 hours. Less than 5% of an oral dose of metoprolol is recovered unchanged in the urine; the rest is excreted by the kidneys as metabolites that appear to have no beta-blocking activity.
Amlodipine
Elimination from the plasma is biphasic with a terminal elimination half-life of about 30-50 hours and 10% of the parent compound and 60% of the metabolites are excreted in the urine.
Special Populations
Hepatic Impairment
Since amlodipine is extensively metabolized by the liver and the plasma elimination half-life (t½) is 56 hours in patients with impaired hepatic function, titrate slowly when administering amlodipine to patients with severe hepatic impairment.
Pediatric
The pharmacokinetic profile of metoprolol extended-release was studied in 120 pediatric hypertensive patients (6-17 years of age) receiving doses ranging from 12.5 to 200 mg once daily. The pharmacokinetics of metoprolol were similar to those described previously in adults. Age, gender, race and ideal body weight had no significant effects on metoprolol pharmacokinetics. Metoprolol apparent oral clearance (CL/F) increased linearly with body weight. Metoprolol pharmacokinetics have not been investigated in patients
Sixty-two hypertensive patients aged 6-17 years received doses of amlodipine between 1.25 mg and 20 mg. Weight-adjusted clearance and volume of distribution were similar to values in adults.
Dosage should be individualized. The recommended initial dose is one tablet of METOLAR AM-25 or METOLAR AM-50 once daily. If necessary, the dose may be increased to two tablets once daily.
Small, fragile or elderly individuals, or patients with hepatic insufficiency can be initiated on separate tablets of metoprolol extended-release and amlodipine 2.5 mg both once daily. The dose of amlodipine can be increased to 5 mg once daily depending on the patient tolerability. When the patient is stabilized on this dose he/she can be shifted to one tablet of METOLAR AM 25/50 once daily.
A patient whose blood pressure is not adequately controlled with metoprolol extended-release or amlodipine monotherapy may be switched to the combination therapy.
For convenience, patients receiving metoprolol extended-release and amlodipine from separate formulations may instead wish to receive a combination formulation containing the same component doses.
Severe bradycardia, Second-or third-degree heart block, cardiogenic shock, de-compensated cardiac failure, sick sinus syndrome (unless a permanent pacemaker is in place), and in patients who are hypersensitive to any component of this product.
Catecholamine Depleting Drugs (e.g. reserpine, monoamine oxidase [MAO] inhibitors)
Catecholamine-depleting drugs may have an additive effect when given with beta-blocking agents. Observe patients treated with METOLAR AM plus a catecholamine depletor should therefore be carefully observed for evidence of hypotension or marked bradycardia, which may produce vertigo, syncope, or postural hypotension.
Drugs Inhibiting CYP2D6
Drugs that inhibit CYP2D6 such as quinidine, fluoxetine, paroxetine and propafenone are likely to increase metoprolol concentration. In healthy subjects with CYP2D6 extensive metabolizer phenotype, coadministration of quinidine 100 mg and immediate-release metoprolol 200 mg tripled the concentration of S-metoprolol and doubled the metoprolol elimination half-life. In four patients with cardiovascular disease, coadministration of propafenone 150 mg t.i.d with immediate-release metoprolol 50 mg t.i.d resulted in two- to five-fold increases in the steady-state concentration of metoprolol. These increases in plasma concentration would decrease the cardioselectivity of metoprolol.
CYP3A4 Inhibitors
Co-administration of a 180 mg daily dose of diltiazem with 5 mg amlodipine in elderly hypertensive patients resulted in a 60% increase in amlodipine systemic exposure. Erythromycin co-administration in healthy volunteers did not significantly change amlodipine systemic exposure. However, strong inhibitors of CYP3A4 (e.g., ketoconazole, itraconazole, ritonavir) may increase the plasma concentrations of amlodipine to a greater extent. Monitor for symptoms of hypotension and edema when METOLAR AM is co-administered with CYP3A4 inhibitors.
CYP3A4 Inducers
No information is available on the quantitative effects of CYP3A4 inducers on amlodipine. Blood pressure should be closely monitored when METOLAR AM is co-administered with CYP3A4 inducers.
Digitalis Glycosides
Both digitalis glycosides & beta-blockers slow AV conduction & decrease heart rate. Concomitant use can increase the risk of bradycardia.
Clonidine
Beta-blockers may exacerbate the rebound hypertension which can follow the withdrawal of clonidine. If coadministered, METOLAR AM tablets should be withdrawn several days before the gradual withdrawal of clonidine. If replacing clonidine with METOLAR AM tablets, the introduction of METOLAR AM tablets should be delayed for several days after clonidine administration has been stopped.
Calcium Channel Blockers
Concomitant use of calcium channel blockers with beta-blockers can increase the risk of bradycardia. Because of significant inotropic and chronotropic effects in patients treated with beta-blockers and calcium channel blockers of the verapamil and diltiazem type, caution should be exercised in patients treated with these agents concomitantly.
General
In clinical trials, amlodipine has been safely administered with thiazide diuretics, beta-blockers, angiotensin converting enzyme inhibitors, long-acting nitrates, sublingual nitroglycerin, digoxin, warfarin, phenytoin, indomethacin, non-steroidal anti-inflammatory drugs, cimetidine, magnesium and aluminum hydroxide antacid, atorvastatin, simvastatin, sildenafil, grapefruit juice, ethanol antibiotics and oral hypoglycemic drugs.
Symptomatic hypotension is possible, particularly in patients with severe aortic stenosis. Because of the gradual onset of action, acute hypotension is unlikely.
Worsening angina and acute myocardial infarction can develop after starting or increasing the dose of amlodipine, particularly in patients with severe obstructive coronary artery disease.
Amlodipine is not a beta-blocker and therefore gives no protection against the dangers of abrupt beta-blocker withdrawal; any such withdrawal should be by gradual reduction of the dose of beta-blocker.
Following abrupt cessation of therapy with certain beta-blocking agents, exacerbations of angina pectoris, and in some cases, myocardial infarction have occurred. When discontinuing chronically administered METOLAR AM, particularly in patients with ischemic heart disease, gradually reduce the dosage over a period of 1-2 weeks and monitor the patient. If angina markedly worsens or acute coronary ischemia develops, METOLAR AM should be reinstated promptly, and measures appropriate for the management of unstable angina should be taken. Warn patients not to interrupt therapy without their physician's advice. Because coronary artery disease is common and may be unrecognized, avoid abruptly discontinuing METOLAR AM in patients treated only for hypertension.
Patients with bronchospastic diseases should, in general, not receive beta-blockers. Because of its relative beta1-selectivity, however, METOLAR AM may be used in patients with bronchospastic disease who do not respond to, or cannot tolerate, other antihypertensive treatment. Because beta1-selectivity is not absolute, use the lowest possible dose of METOLAR AM. Bronchodilators, including beta2-agonists, should be readily available or administered concomitantly.
Avoid initiation of a high-dose regimen of extended-release metoprolol in patients undergoing non-cardiac surgery, since such use in patients with cardiovascular risk factors has been associated with bradycardia, hypotension, stroke and death.
Chronically administered beta-blocking therapy should not be routinely withdrawn prior to major surgery, however, the impaired ability of the heart to respond to reflex adrenergic stimuli may augment the risks of general anesthesia and surgical procedures.
Beta-blockers may mask tachycardia occurring with hypoglycemia, but other manifestations such as dizziness and sweating may not be significantly affected.
Beta-adrenergic blockade may mask certain clinical signs of hyperthyroidism such as tachycardia. Abrupt withdrawal of beta-blockade may precipitate a thyroid storm.
Beta-blockers can precipitate or aggravate symptoms of arterial insufficiency in patients with peripheral vascular disease.
While taking beta-blockers, patients with a history of severe anaphylactic reactions to a variety of allergens may be more reactive to repeated challenge and may be unresponsive to the usual doses of epinephrine used to treat an allergic reaction.
If METOLAR AM is used in the setting of pheochromocytoma, it should be given in combination with an alpha-blocker, and only after the alpha-blocker has been initiated. Administration of beta-blockers alone in the setting of pheochromocytoma has been associated with a paradoxical increase in blood pressure due to the attenuation of beta-mediated vasodilation in skeletal muscle.
Worsening cardiac failure may occur during up-titration of METOLAR AM. If such symptoms occur, increase diuretics and restore clinical stability before advancing the dose of METOLAR AM. It may be necessary to lower the dose of METOLAR AM or temporarily discontinue it. Such episodes do not preclude subsequent successful titration of METOLAR AM.
The systemic availability and half-life of metoprolol in patients with renal failure do not differ to a clinically significant degree from those in normal subjects. No reduction in dosage is needed in patients with chronic renal failure. The pharmacokinetics of amlodipine are not significantly influenced by renal impairment. Patients with renal failure may therefore receive the usual initial dose.
No studies have been performed with metoprolol extended-release in patients with hepatic impairment. Because metoprolol extended-release is metabolized by liver, metoprolol blood levels are likely to increase substantially with poor hepatic function. It is recommended to initiate metoprolol extended-release therapy at lower doses than those recommended for a given indication; and increase doses gradually. Also, amlodipine is extensively metabolized by the liver and the plasma elimination half-life is 56 hours in patients with impaired hepatic impairment. Hence, METOLAR AM tablets should be used with caution in patients with hepatic impairment.
There are no adequate and well controlled studies in pregnant women. Hence, METOLAR AM tablets should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
Metoprolol is excreted in breast milk in very small quantities. It is not known whether amlodipine is excreted in human milk. In the absence of this information, it is recommended that nursing be discontinued while METOLAR AM tablets are administered.
Safety and effectiveness of METOLAR AM tablets in pediatric patients has not been established in patients
In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.
The following are the adverse reactions:
Clinical Trials Experience
Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. The adverse reaction information from clinical trials does, however, provide a basis for identifying the adverse events that appear to be related to drug use and for approximating rates.
Hypertension and Angina: Most adverse reactions have been mild and transient. The most common (>2%) adverse reactions are tiredness, dizziness, depression, diarrhea, shortness of breath, bradycardia and rash.
Heart Failure: In the MERIT-HF study comparing metoprolol extended-release in daily doses up to 200 mg (mean dose 159 mg once-daily; n=1990) to placebo (n=2001), 10.3% of metoprolol extended-release patients discontinued for adverse reactions vs. 12.2% of placebo patients.
The table below lists adverse reactions in the MERIT-HF study that occurred at an incidence of ≥ 1% in the metoprolol extended-release group and greater than placebo by more than 0.5%, regardless of the assessment of causality.
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Post-Operative Adverse Events: In a randomized, double-blind, placebo-controlled trial of 8351 patients with or at risk for atherosclerotic disease undergoing non-vascular surgery and who were not taking beta-blocker therapy, metoprolol extended-release 100 mg was started 2 to 4 hours prior to surgery then continued for 30 days at 200 mg per day. Metoprolol extended-release use was associated with a higher incidence of bradycardia (6.6% vs. 2.4%; HR 2.74; 95% CI 2.19, 3.43), hypotension (15% vs. 9.7%; HR 1.55; 95% CI 1.37, 1.74), stroke (1.0% vs. 0.5%; HR 2.17; 95% CI 1.26, 3.74) and death (3.1% vs. 2.3%; HR 1.33; 95% CI 1.03, 1.74) compared to placebo.
Post-Marketing Experience
The following adverse reactions have been identified during post-approval use of metoprolol extended-release or immediate-release metoprolol. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.
Cardiovascular: Cold extremities, arterial insufficiency (usually of the Raynaud type), palpitations, peripheral edema, syncope, chest pain and hypotension
Central Nervous System: Confusion, short-term memory loss, headache, somnolence, nightmares, insomnia, anxiety/nervousness, hallucinations, paresthesia
Respiratory: Wheezing (bronchospasm), dyspnea
Gastrointestinal: Nausea, dry mouth, constipations, flatulence, heartburn, hepatitis, vomiting
Hypersensitive Reactions: ruritis
Miscellaneous: Musculoskeletal pain, arthralgia, blurred vision, decreased libido, male impotence, tinnitus, reversible alopecia, agranulocytosis, dry eyes, worsening of psoriasis, Peyronie's disease, sweating, photosensitivity, taste disturbance
Potential Adverse Reactions
In addition, there are adverse reactions not listed above that have been reported with other beta-adrenergic blocking agents and should be considered potential adverse reactions to metoprolol extended-release.
Central Nervous System: Reversible mental depression progressing to catatonia; an acute reversible syndrome characterized by disorientation for time and place, short-term memory loss, emotional lability, clouded sensorium and decreased performance on neuropsychometrics
Hematologic: Agranulocytosis, nonthrombocytopenic purpura, thrombocytopenic purpura
Hypersensitive Reactions: Laryngospasm, respiratory distress
Laboratory Test Findings
Clinical laboratory findings may include elevated levels of serum transaminase, alkaline phosphatase and lactate dehydrogenase.
Clinical Trials Experience
Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice.
Amlodipine has been evaluated for safety in more than 11,000 patients in US and foreign clinical trials. In general, treatment with amlodipine was well-tolerated at doses up to 10 mg daily. Most adverse reactions reported during therapy with amlodipine were of mild or moderate severity. In controlled clinical trials directly comparing amlodipine (N=1730) at doses up to 10 mg to placebo (N=1250), discontinuation of amlodipine due to adverse reactions was required in only about 1.5% of patients and was not significantly different from placebo (about 1%). The most common side effects are headache and edema. The incidence (%) of side effects that occurred in a dose related manner are as follows:
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N=275 |
N=296 |
N=268 |
N=520 |
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Other adverse experiences that were not clearly dose related but were reported with an incidence greater than 1.0% in placebo-controlled trials include the following:
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(N=1730) |
(N=1250) |
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For several adverse experiences that appear to be drug and dose related, there was a greater incidence in women than men associated with amlodipine treatment as shown in the following table:
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Male=% (N = 1218) |
(N = 512) |
Male=% (N = 914) |
(N = 336) |
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The following events occurred in 0.1% of patients in controlled clinical trials or under conditions of open trials or marketing experience where a causal relationship is uncertain; they are listed to alert the physician to a possible relationship:
Cardiovascular: arrhythmia (including ventricular tachycardia and atrial fibrillation), bradycardia, chest pain, hypotension, peripheral ischemia, syncope, tachycardia, postural hypotension, postural dizziness, vasculitis
Central and Peripheral Nervous System: hypoesthesia, neuropathy peripheral, paresthesia, tremor, vertigo
Gastrointestinal: anorexia, constipation, dyspepsia1, dysphagia, diarrhea, flatulence, pancreatitis, vomiting, gingival hyperplasia
General: allergic reaction, asthenia1, back pain, hot flushes, malaise, pain, rigors, weight gain, weight decrease
Musculoskeletal System: arthralgia, arthrosis, muscle cramps1, myalgia
Psychiatric: sexual dysfunction (male1 and female), insomnia, nervousness, depression, abnormal dreams, anxiety, depersonalization
Respiratory System: dyspnea1, epistaxis
Skin and appendages: angioedema, erythema multiforme, pruritis1, rash1, rash erythematous, rash maculopapular
Special Senses: abnormal vision, conjunctivitis, diplopia, eye pain, tinnitus
Urinary System: micturition frequency, micturition disorder, nocturia
Autonomic Nervous System: dry mouth, sweating increased
Metabolic and Nutritional: hyperglycemia, thirst
Hemopoietic: leucopenia, purpura, thrombocytopenia
The following events occurred in <0.1% of patients: cardiac failure, pulse irregularity, extrasystoles, skin discoloration, urticaria, skin dryness, alopecia, dermatitis, muscle weakness, twitching, ataxia, hypertonia, migraine, cold and clammy skin, apathy, agitation, amnesia, gastritis, increased appetite, loose stools, coughing, rhinitis, dysuria, polyuria, parosmia, taste perversion, abnormal visual accommodation and xerophthalmia.
Other reactions occurred sporadically and cannot be distinguished from medications or concurrent disease states such as myocardial infarction and angina.
Amlodipine therapy has not been associated with clinically significant changes in routine laboratory test. No clinically relevant changes are noted in serum potassium, serum glucose, total triglycerides, total cholesterol, HDL cholesterol, uric acid, blood urea nitrogen or creatinine,
In the CAMELOT and PREVENT studies, the adverse event profile was similar to that reported previously, with the most common adverse event being peripheral edema.
Post-Marketing Experience
Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliable estimate their frequency or establish a causal relationship to drug exposure.
The following postmarketing event has been reported infrequently where a causal relationship is uncertain: gynecomastia. In postmarketing experience, jaundice and hepatic enzyme elevations (mostly consistent with cholestasis or hepatitis), in some cases severe enough to require hospitalization have been reported in association with use of amlodipine.
Amlodipine has been used safely in patients with chronic obstructive pulmonary disease, well-compensated congestive heart failure, coronary heart disease, peripheral vascular disease, diabetes mellitus and abnormal lipid profiles.
Signs and Symptoms
Overdosage of metoprolol extended-release may lead to severe bradycardia, hypotension and cardiogenic shock. Clinical presentation can also include: atrioventricular block, heart failure, bronchospasm, hypoxia, impairment of consciousness/coma, nausea and vomiting.
Treatment
Consider treating the patient with intensive care. Patients with myocardial infarction or heart failure may be prone to significant hemodynamic instability. Seek consultation with a regional poison control center and a medical toxicologist as needed. Beta-blocker overdose may result in significant resistance to resuscitation with adrenergic agents, including beta-agonists. On the basis of the pharmacologic actions of metoprolol employ the following measures.
There is very limited experience with the use of hemodialysis to remove metoprolol, however metoprolol is not highly protein bound.
Bradycardia: Administer IV atropine; repeat to effect. If the response is inadequate, consider IV isoproterenol or other positive chronotropic agents. Evaluate the need for transvenous pacemaker insertion.
Hypotension:Treat underlying bradycardia, Consider IV vasopressor infusion, such as dopamine or norepinephrine
Bronchospasm: Administer a beta2-agonist, including albuterol inhalation, or an oral theophylline derivative
Cardiac Failure: Administer diuretics or digoxin for congestive heart failure. For cardiogenic shock, consider IV dobutamine, isoproterenol or glucagon
Overdosage might be expected to cause excessive peripheral vasodilation with marked hypotension and possibly a reflex tachycardia. In humans, experience with intentional overdosage of amlodipine is limited.
If massive amlodipine overdose should occur, initiate active cardiac and respiratory monitoring. Frequent blood pressure measurements are essential. Should hypotension occur, provide cardiovascular support including elevation of the extremities and the judicious administration of fluids. If hypotension remains unresponsive to these conservative measures, administration of vasopressors (such as phenylephrine) should be considered with attention to circulating volume and urine output. As amlodipine is highly-protein bound, hemodialysis is not likely to be of benefit.
METOLAR AM-25: Blister pack of 10 tablets
METOLAR AM-50: Blister pack of 10 tablets
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