Amlodipine Dosing for Breakthrough Hypertension
The patient can safely take 2.5-5 mg of amlodipine now at 6:30 pm, as this represents appropriate add-on therapy for inadequately controlled blood pressure on current dual therapy with telmisartan and hydrochlorothiazide. 1
Rationale for Adding Amlodipine
The current BP of 138/98 mmHg indicates inadequate control, particularly with the diastolic reading of 98 mmHg, which exceeds the target of <90 mmHg (or ideally <80 mmHg for optimal cardiovascular risk reduction). 1
The patient is already on two-drug combination therapy (telmisartan 40 mg + hydrochlorothiazide 12.5 mg), and guideline-directed management recommends escalating to three-drug combination therapy when BP remains uncontrolled. 1
The preferred three-drug combination consists of a renin-angiotensin system (RAS) blocker (telmisartan in this case) + a dihydropyridine calcium channel blocker (amlodipine) + a thiazide/thiazide-like diuretic (hydrochlorothiazide). 1
Recommended Amlodipine Dose
Start with amlodipine 2.5-5 mg once daily. 1
The usual dose range for amlodipine is 2.5-10 mg once daily, with 5 mg being a common starting dose for add-on therapy. 1
Amlodipine can be titrated up to 10 mg daily if needed to achieve BP control. 1
Safety and Timing Considerations
It is safe to take amlodipine at 6:30 pm, approximately 11.5 hours after the morning telmisartan dose and 10 hours after the hydrochlorothiazide dose. 1
Medications should be taken at the most convenient time for the patient to establish a habitual pattern and improve adherence; there is no contraindication to evening dosing of amlodipine. 1
Amlodipine has a long half-life and provides 24-hour BP control with once-daily dosing, so the specific time of day is less critical than consistency. 2, 3
Evidence Supporting This Combination
The telmisartan + amlodipine + hydrochlorothiazide combination has demonstrated superior BP-lowering efficacy compared to dual therapy in multiple trials. 2, 4, 5
In the ACCOMPLISH trial, combinations including amlodipine were superior to those including hydrochlorothiazide alone in reducing cardiovascular events among high-risk patients, supporting the addition of amlodipine to existing therapy. 3
The telmisartan/amlodipine combination provides substantial 24-hour BP-lowering efficacy and is well tolerated, with the added benefit of reducing amlodipine-induced peripheral edema when combined with a RAS blocker. 2, 5, 3
Important Caveats
Monitor for dose-related peripheral edema, which is the most common adverse effect of dihydropyridine calcium channel blockers like amlodipine, though this is reduced when combined with telmisartan. 1, 2
Avoid amlodipine in patients with heart failure with reduced ejection fraction (HFrEF), though amlodipine or felodipine may be used if required. 1
The patient should have BP rechecked within 2-4 weeks to assess response to the three-drug combination and determine if further titration is needed. 1
If BP remains uncontrolled on maximal doses of this three-drug combination, consider adding spironolactone or referring to a hypertension specialist. 1