Photos by Chris Thompson

That value-size bottle of vitamin C you keep on hand for the cold and flu season may not appear to have much to do with prescriptions from your doctor. But, in fact, herbs and vitamins can make some of the most commonly used medicines work better.

Usually, it’s the scary interactions between drugs and dietary supplements that get play in the press: Never use St. John’s wort while you’re on certain antidepressants, headlines warn, or you could end up with gastrointestinal symptoms and anxiety. Don’t take iron at the same time as tetracycline, or this antibiotic won’t work as well.

Although it is true that many natural remedies do not mix well with medications (see “Be Alert: Supplements and Drugs That May Not Mix,” below), it is also true that many do. Sometimes taking an herb or dietary supplement can mitigate undesirable side effects of a prescription or over-the-counter (OTC) drug. In other cases, it can help a drug to work better.

To help you understand this potentially confusing topic, we researched five of the most common classes of medications and explain how dietary supplements and herbs may help improve their performance.

What you’re taking: Antidepressants
Some of the most popular antidepressants today—including fluoxetine (Prozac)— are selective serotonin reuptake inhibitor (SSRI) drugs. SSRI drugs work by keeping more serotonin (a brain chemical that plays an important role in mood) in the brain.

Helpful Supplement: Folic acid

  • Why take it: Not everyone feels better when taking fluoxetine for depression, and experts have discovered that people with low levels of folic acid are more likely to be in this nonresponder group (Journal of Affective Disorders, 2000, vol. 60, no. 2). Simply taking folic acid with the antidepressant leads to significantly greater response to the drug. Experts believe that taking folic acid supplements will probably improve the antidepressant action of similar drugs, as well.
  • How to take it: Supplement with 200 mcg to 500 mcg per day, the amount generally found in a multivitamin/mineral.

Helpful Supplement: Ginkgo (Ginkgo biloba)

  • Why take it: Many people taking SSRI antidepressants experience sexual side effects, such as problems with libido, arousal, and orgasm. There is some evidence that taking ginkgo while on SSRI drugs can alleviate sexual dysfunction. In an open trial (a type of study in which the participants know they are not taking a placebo), both men and women who took 60 mg to 120 mg of ginkgo extract each day had an 84 percent success rate for lessening antidepressant-induced sexual dysfunction, including impotence, low libido, inability to become aroused, and inability to have an orgasm (Journal of Sex & Marital Therapy, 1998, vol. 24, no. 2). However, a subsequent double-blind trial of ginkgo in this regard did not find any more benefit than taking a placebo (Human Psychopharmacology, 2002, vol. 17, no. 6). If you’re having sexual problems while taking antidepressants, it’s certainly worth trying ginkgo to see if your sexual health improves.
  • How to take it: A standard daily dose is 120 mg of ginkgo. A high-quality supplement will be labeled as a “standardized extract” and contain 6 percent terpene lactones and 24 percent flavone glycosides.

What you’re taking: Heart Drugs
Widely prescribed statins—a class of drugs known as HMG-CoA reductase inhibitors (such as atorvastatin calcium or Lipitor, lovastatin, and pravastatin)—help block the body’s production of cholesterol. Other commonly prescribed cardiovascular medications include ACE (angiotensin- converting enzyme) inhibitors, such as captopril or enalapril, which help to lower blood pressure by relaxing blood vessels.

Helpful Supplement: Coenzyme Q10 (Co-Q10)

  • Why take it: Statins deplete the body of this essential nutrient, a powerful antioxidant that is highly concentrated in heart cells, where it is essential for the production of energy. Co-Q10 depletion can lead to some serious cardiac risks, such as congestive heart failure and increased free radical damage to LDL cholesterol. (These potential side effects are of particular concern to people who take statin drugs because they are generally already at a higher risk for cardiac problems.) The solution, thankfully, is simple: Take a daily Co-Q10 supplement while using statins (Biofactors, 2003, vol. 18, nos. 1–4).
  • How to take it: Most experts recommend 30 mg to 100 mg of Co-Q10 per day.

Helpful Supplement: Zinc

  • Why take it: Preliminary research has shown that the ACE inhibitor captopril triggers significant loss of zinc in urine and reduced red blood cell levels of zinc. Too little zinc can weaken your immune defenses to infections and make your body less adept at healing wounds.
  • How to take it: While on captopril, it would be wise to supplement with 15 mg of zinc daily, the amount included in a typical multivitamin/mineral.

What you’re taking: Antibiotics
Taking antibiotics (such as amoxicillin, erythromycin, or tetracycline) is a very effective way to kill off disease-causing bacteria in the body. Unfortunately, these drugs also inadvertently destroy helpful bacteria that normally reside in the intestinal tract, sometimes inducing diarrhea and yeast infections.

Helpful Supplement: Probiotics

  • Why take them: Because these strains of “friendly” bacteria and yeast recolonize your gut, they can help prevent antibiotic-induced diarrhea. Specifically, Lactobacillus bacteria (which include the well-known species acidophilus) and Bifidobacterium protect against antibiotic-induced diarrhea (Journal of Nutrition, 2000, vol. 130, no. 2 Suppl).
  • How to take them: Starting the first day you take antibiotics, take a high-quality probiotic for ten days to two weeks to reimplant beneficial flora. Probiotics are present in yogurt and also available as dietary supplements (powder, capsule, tablet, and liquid forms). You’ll want to ingest at least 1 billion live organisms per day, which is equivalent to about 8 ounces of active-culture yogurt. Labels on dietary supplements state the number of live organisms in each dose.

What you’re taking: Oral Contraceptives
Oral contraceptives are one of the most common prescriptions written by doctors, and they are also among the most likely drugs to interfere with numerous nutrients. Major studies show that women taking the pill would do well to consider a variety of dietary supplements (American Journal of Obstetrics and Gynecology, 1976, vol. 125, no. 8). “Sometimes there are mood changes when taking the pill,” says Elena Michaels, PhD, a traditional naturopath based in Santa Clarita, California. “But you can offset any changes by taking sufficient folic acid, magnesium, and B6 and other B vitamins.”

Helpful Supplement: Folic acid

  • Why take it: Folic acid plays many vital roles in the body; it is involved in DNA metabolism as well as cell growth and repair. Lower blood levels of folic acid—one side effect of taking the pill—are associated with health problems such as anemia, cervical dysplasia (a precancerous condition of the cervix), headache, fatigue, and increased risk of heart disease and breast cancer. If a woman with low levels of folic acid does become pregnant, her unborn child is at much higher risk for birth defects, such as spina bifida.
  • How to take it: Women on the pill should aim for 400 mcg of folic acid every day, the amount generally found in a multivitamin/mineral.

Helpful Supplement: Vitamin B6

  • Why take it: Lower vitamin B6 levels (also found in birth control pill users) can increase the risk of depression, insomnia, and heart disease. During the past 20 years, studies have correlated low levels of vitamin B6 in women on the pill with depression, in particular. However, taking 40 mg of vitamin B6 a day alleviates depression for many (Acta Vitaminologica et Enzymologica, 1982, vol. 4, nos. 1–2).
  • How to take it: Women on the pill should take 10 mg to 25 mg of vitamin B6 (the amount found in many multis) to guard against depletion of this important nutrient. Pill users who feel depressed can consider taking the higher amount of 40 mg per day, then assess whether it effectively relieves their depression.

Helpful Supplement: Magnesium

  • Why take it: Magnesium, an essential mineral, performs many important roles in the body, including relaxing muscles, clotting blood, and making new cells. Magnesium deficiency—another common pill side effect—can increase blood pressure, lead to cardiac arrhythmia, promote muscle cramps, and increase the severity of premenstrual syndrome, or PMS.
  • How to take it: Women on the pill should aim for 300 mg of magnesium daily, the amount generally found in a standard multivitamin/mineral.

What you’re taking: Pain Relievers
Whether for arthritis, back pain, or headaches, virtually everyone takes pain relievers at some time. These OTC drugs include acetaminophen (Tylenol), aspirin, ibuprofen (Advil, Motrin), naproxen sodium (Aleve), and other nonsteroidal anti-inflammatory drugs (NSAIDs).

Helpful Supplement: Milk thistle (Silybum marianum)

  • Why take it: Toxic by-products are created when the liver processes acetaminophen. Taking large doses of acetaminophen, taking it frequently, or taking it regularly are all factors that increase the risk of liver damage. Milk thistle can help counteract these effects, especially for daily users (Planta Medica, 1989, vol. 55, no. 5). The premier herb for liver health, milk thistle helps clear toxins and can even regenerate damaged liver cells.
  • How to take it: If your acetaminophen use fits any of the risk factors above, consider supplementing daily with 500 mg of silymarin, the active ingredient in milk thistle.

Helpful Supplement: Vitamin C

  • Why take it: When you take vitamin C soon after taking acetaminophen, it keeps the pain reliever in the body longer because it decreases the urinary excretion of the drug, according to J.B. Houston, PhD, of the University of Manchester’s School of Pharmacy and Pharmaceutical Sciences. In other words, you may be able to take acetaminophen less frequently and maintain the same level of pain relief. In one study, participants took 3 grams of vitamin C 90 minutes after taking 1 gram of acetaminophen. The acetaminophen stayed in their bodies significantly longer and provided added pain relief (Journal of Pharmaceutical Sciences, 1976, vol. 65, no. 8).
  • How to take it: If you want to lengthen the time between doses of acetaminophen, try taking 500 mg to 1,000 mg of vitamin C soon after taking the pain reliever. It’s prudent to start with a lower amount of vitamin C than was used in the study described above, because some people experience stomach upset or loose bowels when taking high amounts (such as 3 grams) of vitamin C. If this doesn’t seem to be a problem for you, it’s fine to increase your dose.

Helpful Supplement: Deglycyrrhizinated licorice (DGL)

  • Why take it: This extract derived from the herb licorice (Glycyrrhiza glabra) can protect the stomach lining from the irritating effects of aspirin and other NSAIDs. It soothes the injured mucous membranes in the stomach and also increases production of mucin, a natural compound that protects the stomach lining from stomach acid (Scandinavian Journal of Gastroenterology, 1979, vol. 14, no. 5).
  • How to take it: Chew one 350 mg tablet of DGL with each dose of aspirin to protect your stomach, especially if it is sensitive.

Helpful Supplement: Folic acid

  • Why take it: Long-term use of high doses of aspirin can cause depletion of folic acid in susceptible individuals. In particular, this becomes a concern if aspirin usage has caused gastrointestinal bleeding.
  • How to take it: If you take aspirin daily, it’s also wise to take 400 mcg of folic acid, the amount generally found in a multivitamin/ mineral.

Oregon-based freelancer Victoria Dolby Toews, MPH, is the author of User’s Guide to Sexual Satisfaction (Basic Health Publications, 2003) as well as User’s Guide to Glucosamine and Chondroitin (Basic Health Publications, 2002).

Disclaimer: The information in this article is not intended to replace the counsel of your doctor or pharmacist, or the informational insert included with your over-the-counter or prescription medication. It is always a good idea to consult your health care practitioner or pharmacist before making any changes or additions to your medication plan, including the addition of any herb or dietary supplement.