Acetazolamide is commonly used to treat idiopathic intracranial hypertension (IIH),
but there is insufficient information to establish an evidence base for its use.
To determine whether acetazolamide is beneficial in improving vision when added to
a low-sodium weight reduction diet in patients with IIH and mild visual loss.
Multicenter, randomized, double-masked, placebo-controlled study of acetazolamide
in 165 participants with IIH and mild visual loss who received a low-sodium weight-reduction
diet. Participants were enrolled at 38 academic and private practice sites in North
America from March 2010 to November 2012 and followed up for 6 months (last visit
in June 2013). All participants met the modified Dandy criteria for IIH and had a
perimetric mean deviation (PMD) between -2 dB and -7 dB. The mean age was 29 years
and all but 4 participants were women.
Low-sodium weight-reduction diet plus the maximally tolerated dosage of acetazolamide
(up to 4 g/d) or matching placebo for 6 months.
The planned primary outcome variable was the change in PMD from baseline to month
6 in the most affected eye, as measured by Humphrey Field Analyzer. Perimetric mean
deviation is a measure of global visual field loss (mean deviation from age-corrected
normal values), with a range of 2 to -32 dB; larger negative values indicate greater
vision loss. Secondary outcome variables included changes in papilledema grade, quality
of life (Visual Function Questionnaire 25 [VFQ-25] and 36-Item Short Form Health Survey),
headache disability, and weight at month 6.
The mean improvement in PMD was greater with acetazolamide (1.43 dB, from -3.53 dB
at baseline to -2.10 dB at month 6; n = 86) than with placebo (0.71 dB, from -3.53
dB to -2.82 dB; n = 79); the difference was 0.71 dB (95% CI, 0 to 1.43 dB; P = .050).
Mean improvements in papilledema grade (acetazolamide: -1.31, from 2.76 to 1.45; placebo:
-0.61, from 2.76 to 2.15; treatment effect, -0.70; 95% CI, -0.99 to -0.41; P < .001)
and vision-related quality of life as measured by the National Eye Institute VFQ-25
(acetazolamide: 8.33, from 82.97 to 91.30; placebo: 1.98, from 82.97 to 84.95; treatment
effect, 6.35; 95% CI, 2.22 to 10.47; P = .003) and its 10-item neuro-ophthalmic supplement
(acetazolamide: 9.82, from 75.45 to 85.27; placebo: 1.59, from 75.45 to 77.04; treatment
effect, 8.23; 95% CI, 3.89 to 12.56; P < .001) were also observed with acetazolamide.
Participants assigned to acetazolamide also experienced a reduction in weight (acetazolamide:
-7.50 kg, from 107.72 kg to 100.22 kg; placebo: -3.45 kg, from 107.72 kg to 104.27
kg; treatment effect, -4.05 kg, 95% CI, -6.27 to -1.83 kg; P < .001).
In patients with IIH and mild visual loss, the use of acetazolamide with a low-sodium
weight-reduction diet compared with diet alone resulted in modest improvement in visual
field function. The clinical importance of this improvement remains to be determined.
clinicaltrials.gov Identifier: NCT01003639.