Can amlodipine 10 mg be taken twice a day
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Can Amlodipine 10 mg Be Taken Twice a Day?
Introduction to Amlodipine and Dosage
Amlodipine is a long-acting calcium channel blocker commonly prescribed for the treatment of hypertension and angina pectoris. It is typically administered once daily, with doses ranging from 5 mg to 10 mg. However, there are questions about whether dividing the daily dose into two administrations could offer better blood pressure control or other benefits.
Compliance and Blood Pressure Control with Once vs. Twice Daily Dosing
Studies have shown that compliance with antihypertensive medication is generally higher with once-daily dosing compared to twice-daily dosing. A clinical trial comparing once-daily amlodipine to twice-daily diltiazem found that while overall compliance was high for both regimens, the patterns of pill-taking were more erratic with twice-daily dosing1. This suggests that once-daily dosing may be more convenient and lead to better adherence, which is crucial for effective blood pressure management.
Efficacy of Dividing Amlodipine Doses
A study specifically investigating the effects of dividing a 10 mg daily dose of amlodipine into two doses found no significant differences in 24-hour blood pressure control, trough plasma amlodipine concentrations, or arterial stiffness compared to once-daily administration2. This indicates that splitting the dose does not provide additional benefits in terms of blood pressure control or pharmacokinetics.
Combination Therapy and Side Effects
When combined with other antihypertensive agents like captopril, once-daily amlodipine has been shown to be effective in controlling blood pressure in patients with moderate to severe hypertension3 4. The combination was well tolerated, with only mild side effects such as ankle edema and flushing reported by a few patients.
Safety and Toxicity Concerns
Amlodipine is generally safe when taken as prescribed, but there are cases of toxicity, especially when taken in excessive amounts or combined with other medications. A case study reported severe amlodipine intoxication in a patient who attempted suicide by ingesting a large quantity of the drug along with other medications6. This underscores the importance of adhering to prescribed dosages and being cautious with polypharmacy.
Conclusion
Current research indicates that taking amlodipine 10 mg twice a day does not offer significant advantages over once-daily dosing in terms of blood pressure control or drug efficacy. Moreover, once-daily dosing is associated with better compliance, which is critical for effective hypertension management. Therefore, it is generally recommended to adhere to the once-daily dosing regimen unless otherwise directed by a healthcare provider.
Sources and full results
Most relevant research papers on this topic
Patterns of compliance with once versus twice daily antihypertensive drug therapy in primary care: a randomized clinical trial using electronic monitoring.
Hypertensive patients show high overall compliance with once or twice daily medication, but erratic pill-taking patterns with twice daily medication may lead to less blood pressure control.
RCT
Highly CitedEffects of dividing amlodipine daily doses on trough drug concentrations and blood pressure control over a 24-hour period.
Divided amlodipine doses did not improve blood pressure control or reduce arterial stiffness in patients with essential hypertension.
Amlodipine and captopril in moderate-severe essential hypertension.
Adding once-daily amlodipine to low dose captopril effectively reduces blood pressure in moderate-severe hypertensive patients, with no discontinuation of therapy.
RCTA double-blind crossover comparison of amlodipine and placebo added to captopril in moderate to severe hypertension.
Amlodipine 10 mg once daily added to captopril significantly improved blood pressure control in patients with moderate to severe hypertension, with few serious side effects.
RCTA double-blind dose-response study of amlodipine in patients with stable angina pectoris.
Amlodipine significantly improves angina symptoms and exercise time in patients with stable angina pectoris, with frequent but mild side-effects.
RCTAmlodipine toxicity complicated by concurrent medications
Amlodipine toxicity can be fatal when combined with other medications, such as sedatives, antihypertensives, oral hypoglycemic agents, and thyroid medications.
Case Report
Very Rigorous JournalOnce daily amlodipine in the treatment of mild to moderate hypertension.
Once-daily amlodipine effectively reduces blood pressure in patients with mild to moderate hypertension, with no significant effects on heart rate or heart rate variability.
RCT[Amlodipine versus nifedipine retard. A randomized double-blind comparative study on long-term efficacy and safety of amlodipine and nifedipine retard in the monotherapy of chronic stable angina pectoris].
Once daily amlodipine offers comparable antianginal and antiischemic efficacy as twice daily nifedipine in treating chronic stable angina pectoris, with a lower incidence of adverse events and more convenient once daily dosing regimen.
RCTThe Phase III, double-blind, parallel-group controlled study of amlodipine 10 mg once daily in Japanese patients with essential hypertension who insufficiently responded to amlodipine 5 mg once daily
Amlodipine 10 mg once daily is superior to amlodipine 5 mg once daily, safe, well-tolerated, and useful for patients with essential hypertension who insufficiently respond to the former.
Rigorous Journal24-hour blood pressure control with the once-daily calcium antagonist amlodipine.
Amlodipine effectively reduces blood pressure for 24 hours after once-daily dosing and is well tolerated in patients with mild to moderate hypertension.
RCT