Hypertensive urgency: no clear difference between nifedipine and labetalol

Clinical bottom line (level 1b-)

  1. Patients with a hypertensive urgency who received labetalol compared with nifedipine were not clearly more likely to have blood pressure controlled at 4 hours.
McDonald et al: American Journal of Emergency Medicine 1993; 11 (5): 460-463
Expires October 2003

The study

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

20 patients (aged mean 47, 50% male) with a diastolic blood pressure > or = 120 mmHg (measured twice after resting supine for 30 minutes)

Excluded if
  • aged < 18
  • on any antihypertensive medication other than diuretics within the last 24 hours
  • blood pressure > or = 250/150 mmHg
  • malignant hypertension
  • hypertensive encephalopathy
  • acute pulmonary edema
  • acute myocardial ischemia
  • myocardial infarction in past 6 months
  • sinus bradycardia < 50 beats/min, second or third degree heart block
  • asthma
  • chronic obstructive lung disease
  • creatinine > 2.0 mg/dl
  • pregnancy


    • Control Group: (n = 10, 10 analysed): nifedipine 10 mg bitten once and swallowed, repeated in 1 hour if diastolic remained > or = 110 mmHg
    Experimental Group: (n = 10, 10 analysed): labetalol 200 mg orally, followed by 200 mg at 2 hours if diastolic > or = 120 mmHg, or 100 mg if diastolic between 110 and 120 mmHg

    100% followed for 4 hours
    Outcome notes:
    • treatment failure : diastolic > or = 110 mmHg after 4 hours

    The evidence

    Outcome Time to outcome CEREERRRR
    (95% CI)    		ARR
    (95% CI)    		NNT
    (95% CI)
    treatment failure 4 hours 0
    (0.0%)    		 2
    (20.0%)    		 %
    (% to %)    		 -20.0%
    (-44.8% to 4.79%)    		 -6
    (NNT = 21 to infinity;
    NNH = 2 to infinity)

    Comments

    1. The study is too small and two short to show any differences between the two therapies
    2. The mean fall in blood pressure was similar for the two groups (~40/25 mmHg)
    3. No patients complained of side-effects in either group.

    Citation

    1. McDonald AJ, Yealy DM, Jacobson S: oral labetalol versus oral nifedipine in hypertensive urgencies in the ED. American Journal of Emergency Medicine 1993; 11 (5): 460-463
    Contributor: Chris Ball and Clare Wotton, October 1999
    Reviewer:

    Clinical Question.
    Patient malignant hypertension
    Intervention or Exposure labetalol
    Comparison nifedipine
    Outcome lowered blood pressure