Prevention of cardiovascular (CV) events requires prompt and sustained control of BP according to targets set by evidence-based guidelines. The speed of titration is important. Too rapid, and we up-titrate before knowing the full response; too slow and we leave the patient at risk of CV events.
- Prevention of early recurrent stroke after TIA requires urgent risk factor reduction including BP control. Initiating antihypertensive medication rapidly after TIA in prospective population-based and cohort studies found reductions in expected stroke incidence.
To judge titration—when to change dose or change drug—requires knowledge of the size and rate of BP reduction of different doses of different agents.
A 2011 meta-analysis in Hypertension found that estimates of the max efficacy of BP agents can be made early after starting therapy.
- This meta-analysis included 18 studies that randomized a total of 4168 patients.
- All trials used either seated or supine diastolic BP for inclusion criteria, thus patients with isolated systolic hypertension were not recruited into any trial.
- Mean ages ranged from 51 to 58.4 years. Drug half-lives varied from 2 to 24 h.
- Medications included across the 18 studies: ACEi (captopril, enalapril, imadipril, lisinopril, spirapril, urapidil), ARB (irbesartan, losartan, telmisartan), CCB (amlodipine, diltiazem, isradipine, nicardipine, nifedipine), thiazides (chlorthalidone, methylchlorothiazide), BB (betaxolol, metoprolol), other (prazosin)
- Averaging across all doses showed the time to reach 50% of predicted maximum effect was approximately 1 week. This timing was similar for diastolic and systolic BP changes.
- Figures 2 and 3 show change in mean systolic and diastolic BP, respectively, over the first 8 weeks of treatment together with a plot of average change (with 95% CI) predicted from the model. The graphs show that for the majority of treatments, around half the full reduction in BP occurs during the first week of therapy, with lesser reductions in subsequent weeks.
The authors concluded that estimation of maximal effect could be made between 1 and 2 weeks after initiation of antihypertensive therapy, although drug class effects on speed of titration were not predictable. Such knowledge may reduce time spent being exposed to medication that is likely to provide no benefit and allow quicker appropriate effective prescribing, which could be crucial in the days and weeks after an acute vascular event.