Side Effects of Vasodilator Drugs

Some of the side effects of vasodilator drugs are just temporary. The following side effects usually pass after the person's body gets used to the medicine.

  • Loss of appetite
  • Headache
  • Diarrhea
  • Nausea or vomiting

Other side effects call for medical attention. If any of the following side effects occurs, a patient should check with his or her doctor.

  • Abnormal heart rhythm
  • Pounding heartbeat
  • Dizziness or lightheadedness
  • Sneezing, respiratory congestion, itching, skin rashes or other allergic reactions)
  • Low blood pressure
  • Shallow, dry cough
  • Fainting
  • Weight gain
  • Fluid retention
  • Sleepiness or weakness
  • Abnormal sensitivity to sunlight, resulting in severe sunburn or rash
  • Pain in joints or back
  • Unusual bleeding (like nosebleeds)
  • Unusual changes in appearance of skin (rash, change in coloration)

In general, older people tend to be more sensitive to the side effects (especially dizziness and lightheadedness) of vasodilators.

grapefruit juice
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If you're taking vasodilator drugs, you shouldn't drink grapefruit juice.

Patients who are taking vasodilators shouldn't take any other medicines (either prescription or over-the-counter) or dietary supplements (including herbal remedies) without first talking with their doctor. The following substances may intensify the effects of vasodilators and lead to severe low blood pressure:

  • Other vasodilators, unless prescribed as part of a combination therapy
  • Alcohol, which is itself a vasodilator
  • Medications for sexual dysfunction
  • Nicotinic acid, a form of vitamin B3 that is sometimes used as a cholesterol-reducing drug
  • Grapefruit juice, which interferes with the liver's ability to rid the body of vasodilators and many other substances. This could lead to a buildup of vasodilators to dangerous levels in the body.

Substances that can counteract the effects of some vasodilators and increase blood pressure include:

  • Aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs)
  • Narcotics (prescription-strength painkillers)

In addition, some over-the-counter medications for cough, colds, flu, sinus problems, hay fever, and asthma, as well as those for bloodshot (red) eyes or appetite control, may adversely react with vasodilators.

To learn more about vasodilator drugs, take a look at the links on the next page.