IIH

The short version: for IIH, the strongest evidence points to weight loss and GLP-1 drugs, not surgery or acetazolamide alone, but the evidence base is thin and funded by the people who profit from the drugs.

Idiopathic intracranial hypertension (IIH) is a condition where high pressure inside the skull threatens vision and causes disabling headaches. The standard approach—acetazolamide, a diuretic—has weak evidence behind it. A 1982 review noted that acetazolamide reduces CSF production by a variable 6% to 57% and that effect wears off within hours [4]. That is not a strong foundation for a drug you take for years.

The most interesting new evidence is for GLP-1 receptor agonists, the diabetes and weight-loss drugs. A 2025 systematic review pulled together one small randomized trial and several large database studies [6]. The randomized trial of exenatide in 15 women found a placebo-corrected drop in intracranial pressure of about 5-6 cm of CSF at 2.5 hours and at 24 hours, and a reduction of about 7.7 headache days per month at 12 weeks [6]. The database studies, each with hundreds to thousands of patients, found that people prescribed GLP-1 drugs had roughly half the risk of vision loss, new headaches, and needing a shunt over the next year [6]. These are big effects.

But there are problems. The database studies are retrospective and come from TriNetX, a commercial health data network. They compare people who got a GLP-1 drug to people who did not, but the two groups may differ in ways the matching cannot fix—people who get these drugs may be more motivated, healthier, or better monitored. The randomized trial was tiny, funded by the manufacturer (AstraZeneca makes exenatide), and lasted only 12 weeks [6]. No long-term safety data exists for GLP-1 drugs in IIH specifically. These drugs also cause nausea, vomiting, and diarrhea in most people, and they are expensive.

Weight loss surgery also works. A 2020 prospective study of 16 obese women found that laparoscopic sleeve gastrectomy led to an average BMI drop from 46 to 28 at 12 months, and all but 2 had complete resolution of IIH symptoms [2]. That is a dramatic result, but surgery carries its own risks and is not for everyone.

The surgical options for vision-threatening IIH—optic nerve sheath fenestration and venous sinus stenting—have some evidence. A 2015 review reported that fenestration improves vision in about 36% of eyes and headaches in about 70% of patients, but a 1993 study found a late failure rate of 35% at 3-5 years [1, 3]. Venous sinus stenting, studied in a 2017 prospective trial of 13 patients, reduced opening pressure from 42 to 22 cm H2O on average and improved visual fields by about 5 dB, but the study had no control group and the patients served as their own controls [5]. Stenting also requires lifelong antiplatelet drugs and carries risks of headache, stent migration, and rare but serious bleeding.

The bottom line: if you have IIH and are overweight, the most evidence-backed approach is weight loss, whether through diet, GLP-1 drugs, or surgery. Acetazolamide is a weak stopgap. Surgery for vision rescue works but has high failure rates over time. The evidence for all of these is modest, short-term, and often funded by the people selling the intervention.

My call: weight loss and GLP-1 drugs are the most promising options, but the evidence is moderate at best and comes with significant caveats. Confidence: moderate.