Severe hypertension: more rapid fall in diastolic blood pressure and fewer side-effects with nifedipine.

Clinical bottom line (level 1b)

  1. Patients with severe hypertension who had oral nifedipine compared with oral clonidine had a more rapid fall in blood pressure (NNT = 2 at 45 minutes) , however more were likely to have a return to severe hypertension within 6 hours (NNH = 4 at 6 hours) .
  2. There were fewer side-effects with nifedipine (NNT = 3 at 6 hours) .
Jaker et al: Archives of Internal Medicine 1989; 149: 260-265
Expires September 2003

The study

Double-blinded concealed randomised trial with intention-to-treat
Setting: emergency department university hospital, USA

51 patients (aged range 27 to 73 years; mean 48, 61% female) with initial diastolic blood pressure >120 mmHg (mean 210/130). 31 patients were found at routine blood pressure check; 20 patients presented with mild symptoms (e.g headache, dizziness, weakness)

Excluded if
  • malignant or accelerated blood pressure (elevated blood pressure with evidence of end-organ damage: grade III, IV hypertensive retinopathy, acute renal failure, hypertensive encephalopathy, acute pulmonary oedema, or acute MI)
  • valvular heart disease
  • aortic dissection
  • chronic renal insufficiency (Cr 265 mmol/dl or more)
  • recent cerebrovascular accident
  • recent myocardial infarction or ischaemia
  • CABG
  • congestive heart failure
  • alcohol withdrawal
  • pregnancy
  • known allergy to study drugs


    • Control Group: (n = 28, 28 analysed): 0.1 mg of clonidine po, then repeated hourly to a maximum 0.6 mg and placebo
    Experimental Group: (n = 23, 23 analysed): 20 mg nifedipine po and placebo

    100% followed for 6 hours
    Outcome notes:
    • side effects : mild headache, light-headedness, drowsiness, facial flushing

    The evidence

    Outcome Time to outcome CEREERRRR
    (95% CI)    		ARR
    (95% CI)    		NNT
    (95% CI)
    diastolic blood pressure < 120 mmHg 45 minutes 6
    (21.4%)    		 19
    (82.6%)    		 -286%
    (-703% to -85%)    		 -61.2%
    (-82.9% to -39.5%)    		 2
    (1 to 3)
    diastolic blood pressure < 120 mmHg 6 hours 22
    (78.6%)    		 22
    (95.7%)    		 -22%
    (-51% to 2%)    		 -17.1%
    (-34.4% to 0.25%)    		 6
    (NNT = 3 to infinity;
    NNH = 400 to infinity)
    recurrence of diastolic > 120 mmHg 6 hours 1
    (3.57%)    		 7
    (30.4%)    		 -752%
    (-6333% to -13%)    		 -26.9%
    (-46.9% to -6.84%)    		 -4
    (-15 to -2)
    side effects 6 hours 17
    (60.7%)    		 7
    (30.4%)    		 50%
    (0% to 75%)    		 30.3%
    (4.19% to 56.4%)    		 3
    (2 to 24)

  • All clonidine responders had < 0.4mg in total. Main side-effect was sedation (ranging from drowsiness to a deep sleep).
  • All patients on nifedipine had a fall in diastolic blood pressure within 2.5 hours - only half of patients on clonidine had responded by then.

    • Comments

    1. All patients had longstanding hypertension: many admitted poor compliance with antihypertensive medication.
    2. The problem of recurrent hypertension could be overcome by repeated dosing (like clonidine). Alternatively a longer-acting version of nifedipine may be beneficial.

    Citation

    1. Jaker M, et al: Oral nifedipine versus oral clonidine in the treatment of urgent hypertension. Archives of Internal Medicine 1989; 149: 260-265
    Contributor: Nick Shenker and Chris Ball, Sepetember 2000
    Reviewer:

    Clinical Question.
    Patient severe hypertension
    Intervention or Exposure nifedipine
    Comparison clonidine
    Outcome fall in blood pressure