DEAR DR. ROACH: I am a 74-year-old woman who was diagnosed with open angle glaucoma several years ago. My ophthalmologist has directed me to use Simbrinza three times a day in my right eye and Lumigan in both eyes at bedtime. I have been doing this for over a year. Both my eyes are always red. My right eyelid is very red and swollen, and it tears in cold weather.

The patient information guide from Simbrinza says to use it no more than twice a day. I talked to my doctor about this last time I saw him and didn’t get a satisfactory response.

My eye pressure was down to 16 mmHg, which is good, but I am concerned that I am exceeding the manufacturer’s instructions for Simbrinza and clearly having side effects.

Is this just physician arrogance? I am tempted to resort to using Simbrinza twice a day, but I have no way of checking my eye pressure if I do this. — P.W.

ANSWER: Most of the studies on the combination eye drop brinzolamide and brimonidine (Symbrinza) used the drug three times daily, and the physician package insert for the drug instructs that it should be used three times daily. The patient information sheet, however, says twice daily. This is true for the patient information sheets published in the United States, Canada, and the United Kingdom.

This is unique in my experience. I called the manufacturer who agreed that this is unusual, but they haven’t yet gotten back to me on what they planned to do about it.

I did find a study showing that twice-daily Symbrinza is effective at reducing eye pressure, which, in turn, reduces the risk of glaucoma progression, including vision loss.

A pressure level of 16 mmHg might be appropriate for you, but this a decision that your ophthalmologist needs to make, specific for your anatomy and stage of glaucoma. (Glaucoma is a disease of the optic nerve that is usually associated with high eye pressure but can occur with normal eye pressure. Furthermore, not everyone with high eye pressure will get optic nerve damage.)

Although it’s possible Symbrinza is causing the side effect of redness and tearing, Lumigan is more likely to be associated with these symptoms. It is certainly wise to discuss changing your medication with your ophthalmologist, and I caution you against stopping it before discussing it.

I would say that it is not arrogance on the part of your physician; it really seems to be a miscommunication by the drug companies about how frequently to dose the medication.

DEAR DR. ROACH: I’m on famotidine for the past five years due to gastroesophageal reflux disease (GERD). My question is, am I harming myself? I’m currently taking two 40-mg pills per day. — Anon.

ANSWER: All medicines have the possibilities for side effects, so I don’t recommend taking medicines that you don’t need. I will often have my patients try going without their daily famotidine or a similar medicine (a class called histamine H2 blockers, which decrease the amount of acid the stomach makes but not to the level that proton-pump inhibitors do). Often, people can do very well by just taking them occasionally, but others really do need daily medicine to prevent real discomfort.

Serious side effects from H2 blockers are rare. Like PPIs, they can sometimes cause low B12 levels. Headaches and agitation are sometimes reported. One H2 blocker, ranitidine, has had manufacturing contamination with NDMA, a carcinogen, but this has not occurred with famotidine.

If you need daily famotidine, the potential for harm is low.

EDITOR’S NOTE: Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu or send mail to 628 Virginia Dr., Orlando, FL 32803.