Antihistamines such as Benadryl (diphenhydramine) often make people drowsy. No surprise.

Antibiotics frequently cause diarrhea and digestive upset because they wipe out helpful intestinal bacteria along with the infection.

Doctors often warn patients about such predictable side effects. But other side effects may slip past the experts because they are unexpected.

Antidepressants such as Prozac, Paxil and Zoloft belong in a class called SSRIs (selective serotonin reuptake inhibitors). Hardly anyone is surprised if such a medication causes anxiety or insomnia. Psychological side effects seem consistent with a drug that affects the brain.

New research suggests, though, that these SSRI antidepressants also increase the risk for bleeding ulcers (Archives of General Psychiatry, July 2008). These drugs have been on the market for two decades, but only in the past several years have researchers recognized a link between upper GI bleeding and these antidepressants.

Part of the delay is because our medical system is fragmented. Psychiatrists prescribe antidepressants, but they rarely see people with serious digestive distress. Gastroenterologists see people with bad bellyaches, but may not associate a hemorrhage in the stomach with an antidepressant.

When the right hand doesn't know what the left hand is doing, patients can suffer. Uncoordinated care can lead to complications from many medications.

Take antibiotics, for example. Doctors often prescribe drugs such as Cipro or Levaquin for sinus or urinary-tract infections. One side effect of these medications that might come as a surprise is tendon rupture.

One reader shared this story: "I took Levaquin to treat a lung infection. After five days, I noticed tightness in my left Achilles' tendon that hampered my ability to walk. Three days later, my left ankle was so swollen, I could hardly hobble. An MRI showed a completely severed Achilles' tendon. I needed surgery and then spent six weeks in a wheelchair."

Who would guess that a snapped Achilles' tendon could be the consequence of treating bronchitis with an antibiotic?

Hundreds of drugs have unexpected side effects. The popular class of reflux medications that includes Aciphex, Nexium, Prilosec and Protonix has been linked to hip fractures (Journal of the American Medical Association, Dec. 27, 2006). Because these heartburn drugs are so effective at suppressing acid, they may interfere with the absorption of certain nutrients such as calcium. Theoretically, this could contribute to weakened bones.

The doctors who deal with patients' heartburn symptoms usually aren't consulted if a patient breaks a hip. The orthopedic surgeons who fix broken hips may not link such fractures to medication taken for reflux.

It can take a long time for the Food and Drug Administration to warn the public about unexpected drug side effects, such as tendon rupture with Cipro-type antibiotics. Even though epilepsy medicines have been on the market for many decades, it is only now that the FDA is considering a black box warning about the potential for these drugs to cause suicidal behavior.

To help the FDA discover unanticipated reactions to prescription medications, such side effects should be reported to MedWatch (www.fda.gov/medwatch/).

Q: My brother-in-law sent me an e-mail about how to remove ticks. It was attributed to a school nurse who suggested applying a glob of liquid soap to a cotton ball and covering the tick with the cotton ball for 20 seconds. Presumably, when you remove the cotton ball, the tick will come out on its own and be stuck to the cotton ball.

Is this really a good way to remove ticks? We are having a bumper crop this year.

A: According to Snopes.com, this e-mail has been circulating on the Internet for more than two years. It sounds credible, but it is not true. Putting liquid soap, petroleum jelly, Vicks VapoRub, fingernail polish or any other goo on a tick will not make it let go faster. Aggravating a tick might cause it to regurgitate saliva into the bite, increasing the risk of infection.

The Centers for Disease Control and Prevention recommend grasping the tick with tweezers as close to the skin as possible. Use a gentle, steady motion to pull the tick straight away from the skin.

Prompt removal reduces the risk of infection. Symptoms such as rash, fatigue, chills, fever, headache, muscle and joint aches could signal either Lyme disease or Rocky Mountain spotted fever. Both require prompt medical attention.

Q: Five years ago, I developed duodenal ulcers after taking Fosamax for six weeks. I was also taking ibuprofen for headaches at the same time.

Last year, after taking baby aspirin for a few months, an endoscopy revealed more ulcers. I was diagnosed with H. pylori and treated with antibiotics.

I have bad osteoarthritis pain in my right knee and hip and would love to take ibuprofen instead of Tylenol, but I don't want to take omeprazole long term and don't want to risk another ulcer. Since the H. pylori is gone, could I risk the ibuprofen? Or is there some other agent I could take that would relieve the pain without causing ulcers?

A: The combination of Fosamax with the nonsteroidal anti-inflammatory drug (NSAID) ibuprofen was a prescription for trouble. Both medications can cause ulcers. A study of Fosamax together with a different NSAID, naproxen, showed that ulcers were more likely in women taking both medicines (Archives of Internal Medicine, Jan. 8, 2001).

Helicobacter pylori (H. pylori) is a stomach infection that increases the risk of ulcers. Even without H. pylori, you might still be susceptible to ulcers if you take aspirin or an NSAID.

We are sending you our Guides to Digestive Disorders and Alternatives for Arthritis, with information on arthritis drugs that are less likely to cause ulcers as well as nondrug approaches to relieve arthritis pain. Anyone who would like copies, please send $4 in check or money order with a long (No. 10), stamped (59 cents), self-addressed envelope to: Graedons' People's Pharmacy, No. AAG-3, P.O. Box 52027, Durham, NC 27717-2027. Ask your doctor about either Disalcid or Trilisate, anti-inflammatory drugs that are less likely to cause stomach irritation.

Q: I have read your articles on licorice raising blood pressure, but you don't state if it is black licorice or both red and black licorice.

I have never suffered from high blood pressure, and I enjoy red licorice once in a while. I don't notice any side effects from eating it. Is it safe?

A. Red licorice is totally safe. It doesn't contain the ingredient (glycyrrhizin) found in black licorice that might raise blood pressure.

"The People's Pharmacy with Joe and Terry Graedon" airs Saturday at 7 a.m. on WVTF (89.1) and at 4 p.m. Saturdays and Sundays on RADIO IQ (89.7).