Clinical News
MEDICAL AND PRODUCT UPDATES

TRAVOPROST IOP CONTROL
Long-lasting effect measured

A recent study of 21 primary open- angle glaucoma patients conducted by Harvey B. DuBiner, M.D., of the Clayton Eye Center in Morrow, Ga., offered evidence that the new prosta-glandin analogue, travoprost 0.004% (Travatan, from Alcon) exerts a beneficial effect on IOP for at least 84 hours after a dose is taken. This could be especially significant for less compliant patients who are likely to miss a dose.

Perhaps even more important, patients recorded impressively flat diurnal curves, with minimal fluctuation. Diurnal fluctuation has recently been categorized as a risk factor in glaucoma, (Asrani et al.) and is positively correlated with visual field loss.

After 25 years, smokers who quit had a lower risk of cataract formation, but not as low as the risk for those who never smoked.

Following a washout from previous medications, Dr. DuBiner established baseline pressures at 4-hour intervals over a 24-hour period. Patients who were included in the study presented with IOPs between 24 and 36 mm Hg at 8 a.m., and 21 and 36 mm Hg at 12 p.m.

While taking travoprost, all diurnally adjusted IOP changes from baseline were statistically significant at every time point; this was true as long as 84 hours after a dose. Dr. DuBiner reported that the medication was well-tolerated by all subjects, and no adverse events were reported.

Although the study was too small to be considered definitive, it suggests that travoprost minimizes diurnal fluctuation and has a continuous, significant effect on IOP for considerably longer than 24 hours. Although Dr. DuBiner stresses that the study shouldn't be construed as an argument for alternative dosing regimens, it does suggest that rescue therapy may not be necessary if a patient misses an occasional dose.

SMOKING AND CATARACTS
Quitting helps -- but not starting is better

A study reported in a recent issue of the American Journal of Epidemiology found that the risk of cataract formation decreases over time once an individual stops smoking. However, even after 20 years, the risk is not as low as the risk for those who never smoked.

Dr. June Weintraub and colleagues from Harvard Medical School examined data from thousands of participants in the Nurses Health Study and Health Professionals Follow-up Study. After adjusting for age and risk factors, including the number of cigarettes smoked per day, the data showed that smokers who had quit 25 or more years earlier had a 20% lower risk of cataract than current smokers, but neither group approached the lower risk associated with those who had never smoked (RR= 0.64). This was true regardless of the type of cataract studied.

Dr. Weintraub observes that this supports the hypothesis that smoking causes irreversible damage to the lens.

NSAID INTERACTION
Latanoprost vs. brimonidine

Many glaucoma patients take non-steroidal anti-inflammatory drugs (NSAIDs) for a variety of health problems, including arthritis and headache. A recent study conducted at the University of Texas Health Science Center in San Antonio found that the effectiveness of some glaucoma medications can be affected by concurrent use of NSAIDs.

The study was a prospective, double-masked, randomized clinical trial, involving 20 subjects with ocular hypertension and open-angle glaucoma.

It compared the efficacy of once-daily latanoprost ophthalmic solution (Xalatan) to that of twice-daily brimonidine tartrate ophthalmic solution (Alphagan) when subjects were also taking indomethacin, an oral NSAID commonly prescribed for arthritis. (Note that the recommended dosage of brimonidine is one drop twice or three times daily.)

Data showed:

• After 1 week of indomethacin treatment, the mean IOP reduction in eyes treated with latanoprost once-daily (morning administration) was 25% (4.7 mm Hg); eyes treated twice a day with brimonidine showed an IOP reduction of 14% (2.6 mm Hg).
• After 2 weeks of indomethacin treatment, latanoprost maintained its IOP reducing effect. Brimonidine's effect became statistically insignificant compared to baseline.
• Latanoprost significantly increased ocular blood flow, although the effect was diminished during indomethacin treatment. Brimonidine didn't alter ocular blood flow significantly, with or without concurrent indomethacin.

The study was reported in the January issue of the American Journal of Ophthalmology.