It’s common to blame problems in the bedroom on our aging bodies or on stress related to such things as kids, finances and marriage. But a lesser-known culprit may reside in our own medicine cabinets: Some of the most widely used drugs, including statins, can produce unexpected changes in sexual arousal and performance.

When prescribing a medication, a physician will typically mention specific guidelines and need-to-know information — for instance, make sure to take each dose with food, avoid alcohol or expect to feel some nausea. However, one topic that isn’t always discussed is how certain drugs may affect a patient’s sex life.

That should change, says Albert Wertheimer, a professor of pharmacy administration at Temple University, and Patricia Bush, a professor emeritus at Georgetown University School of Medicine. They recently co-authored “Your Drugs & Sex: How Prescription & Non-Prescription Drugs Can Affect Your Sex Life,” and discussed the book in a recent interview. Below are excerpts from that conversation.

Q: Many people assume that their doctors would notify them if a medication could significantly influence their sex lives, but is this not typically the case?

Wertheimer: Most people 50 years old and over take drugs for conditions like diabetes, hypertension, high cholesterol, gout, asthma, depression, arthritis, allergies, gastroesophageal reflux disease — and many of these drugs cause profound effects on sexual performance. Most patients assume that declining performance is due to aging, and physicians are not schooled in this area. Often, even if patients have a suspicion the change could be due to a drug, they are too timid to inquire.

Bush: The problem right now is that patients don’t ask about how drugs will affect their sex lives, and the doctors don’t tell. Why don’t the doctors tell? Because the patients don’t ask.

Q: What kinds of unintended sex-related effects can prescription and over-the-counter medications have?

Bush: Cholesterol-lowering drugs, statins, antidepressants, anti-anxiety and anti-psychotic drugs, antifungals, anti-ulcer and anti-epileptic drugs, oral contraceptives and cancer drugs can all have consequences on sexual arousal and performance. The kinds of things that they can cause as side effects include erectile dysfunction, difficulty achieving orgasm, ejaculation failure, impotence, decreased desire, pain during intercourse and lower testosterone.

Wertheimer: Sleeping pills decrease interest in sex, and the same thing happens with many antihistamines for allergies. Antidepressants make ejaculation difficult to achieve, so patients with premature-ejaculation problems can use antidepressants to help.

Q: Why is it important that people be aware of these lesser-known side effects?

Bush: People are living longer, and in a lot of ways that’s a good thing because we are treating the chronic illnesses like diabetes, depression and high blood pressure that people have. As a result, there’s been a big increase in medicine use altogether in the last years.

Because people are taking more drugs, the problem of sexual dysfunction caused by medicines is growing. Another big issue is that as people get older, they have more health issues that can then interact with these drugs, so actually the side effects get worse and are more likely to happen. For instance, aging itself can cause failures in sexual performance, let alone compounding issues like diabetes and so on.

Q: What can patients do if a drug they have been prescribed seems to have negative sexual side effects?

Wertheimer: I recommend they chat with their physician and look up more information about their condition and drugs used to treat it. However, generally physicians know very little about if certain combinations of drugs might cause sexual difficulties. The answer is to experiment and change one of the drugs to see if it makes a difference. If one or more drugs are involved, our book lists other drugs for the same indication that are not usually associated with sexual-function problems.

Bush: Another important thing to know is how to find good information. There’s just a whole lot of rubbish out there about medications on the Internet, so the reliable Web sites we recommend for looking up drug information are the National Library of Medicine’s MedlinePlus [] and the Food and Drug Administration’s Drugs@FDA

For example, hydrochlorothiazide, or HCTZ, is one of the most common drugs given for blood pressure, but it’s also a major cause of erectile dysfunction because it’s a diuretic. But there’s a huge category of drugs that treat blood pressure, so you can go to your physician and tell him you want to try some other things.