What are the most common side effects and who is at higher risk?

The short version: the evidence for combining all three of these glaucoma drugs is thin, and the long-term safety data is essentially absent.

The retrieved records do not directly test the triple combination you are asking about. One manufacturer-funded trial compared bimatoprost/timolol against brinzolamide/timolol fixed combinations, not against a triple therapy [1]. Another record is a pharmacogenetics review of CYP2D6 variants and beta-blocker response, which is about timolol metabolism, not about the three drugs you named [2]. The rest of the retrieval is off-topic: one record covers theophylline dosing in asthma [4], and another covers dental caries in COPD patients [5]. None of these answer your question.

What the records do show is that each drug class lowers eye pressure through a different mechanism, and that combining two drugs from different classes is a common clinical strategy. But the evidence for stacking three is extrapolation from pairwise combinations. No retrieved study tracks long-term outcomes like vision loss or optic nerve damage on triple therapy. No retrieved study compares triple therapy against a true untreated group. The safety data that exists is short-term: redness, irritation, and blurred vision are the common complaints [3].

The honest call: the evidence base for this triple combination is weak, and the long-term safety data does not exist in these records. If you are on all three, the question is not whether they lower pressure—they do—but whether the added benefit of the third drug justifies its added side effects and cost. That question is not answered by anything retrieved here.

Confidence: low. The evidence does not support a firm verdict on triple therapy, and the absence of long-term safety data is a real gap, not a reassurance.