Herbal and vitamin supplements have been growing in popularity in the past few years, but local pharmacists warn that just because a supplement can be purchased over-the-counter does not guarantee that it’s safe.

“Natural does not always mean safe, and [herbal supplements] are not harmless, as many people seem to think,” said Roger Maharry, pharmacist at Drugtown, 500 Main St.

Mike Rhodes, pharmacist at Rhodes Apothecary, 218 Main St., said he has noticed a definite increase in the purchase and use of herbal supplements — an increase that he said will cause more instances of dangerous interactions between prescription and herbal medicines.

Rhodes said the two most common interactions to avoid are Prozac with St. John’s Wart and Coumadin with ginkgo.

“Prozac and St. John’s both increase the serotonin level; that level may get too high if both are used,” he said. “Coumadin is a blood-thinner, and ginkgo also has blood-thinning agents.”

Ken Hampson, pharmacist at the McFarland Clinic Pharmacy, 1215 Duff Ave., said there is not a lot of concrete information about possible drug interactions available yet because, until recently, supplements were not as popular with the general public. A recent CNN study estimated that 60 million Americans regularly take herbal or vitamin products.

“Because there is not a lot of information available, we always defer the individual back to his or her physician. The physician is familiar with that individual’s circumstances and is better equipped to make that type of decision,” Hampson said.

Maharry said part of the confusion is that the U.S. Food and Drug Administration, which regulates prescription drugs and other products, does not regulate most herbal supplements.

“We don’t have definitive answers. Several publications have drug interaction theories, but we don’t really know,” he said.

Maharry said the best way to avoid unsafe situations is to be open with doctors and pharmacists so they can check for possibly hazardous interactions.

“The complicating part is that people don’t always mention that they are taking supplements. We can check and cross-reference for possible interactions if we are made aware,” he said.

Publications such as the “Comprehensive Database of Natural Medicines” provide information on possible interactions, Maharry said.

Rhodes said it is also important to follow the recommended dosages for herbal products and vitamin supplements.

“Read up on the supplements you’re considering. Ask questions, and don’t start with the maximum dosage, and certainly don’t take more than the maximum dosage,” he said.

“Find a reliable brand, check the label, and above all, consult your doctor,” he said.