A study of the efficacy of felodipine given once or twice daily in the management of elderly hypertensive patients.

The use of medication given once daily in clinical practice may lead to inadequate control of blood pressure (BP) over 24 h because medication is frequently titrated at the time of peak effect. Twenty-three patients aged 65-84 completed a study in which they received placebo, felodipine 2.5 mg once daily, felodipine 2.5 mg 12-hourly, and felodipine 5 mg once daily in a randomized, double-blind crossover design. BP response was assessed in the clinic 24 h after medication and by 24 h ambulatory monitoring. The trough/peak ratio was defined as the fall in BP in the 23rd and 24th hour post dose divided by the fall in BP in the 3rd and 4th hour post dose. BP fell with all three regimes and the clinic BPs did not differ from each other but were lower than placebo. Peak BP responses from the ambulatory BP monitor recording were similar with each dose but a greater percentage of the effect was maintained prior to the morning dose with 2.5 mg 12 hourly and 5 mg once daily. Felodipine 2.5 mg once daily reduces BP and in some people this effect persists for 24 h. However if this dose is used BP should be measured prior to the dose of the drug to ensure that 24 h control is maintained. Felodipine 5 mg once daily and felodipine 2.5 mg b.d. were equally effective at maintaining control and there was no significant advantage in using the twice daily regime. If felodipine 5 mg once daily or higher doses are used BP can be titrated post dose with the knowledge that more than 75% of the effect will still be present prior to the next dose of the drug. Thus once daily felodipine extended release (ER) 5 mg or more can be used effectively to maintain BP control over 24 h in clinical practice. In some elderly patients felodipine ER 2.5 mg once daily is an adequate regime.