June 1999

Information for Consumers

Diet Pills and Heart Problems

  • Have you ever taken the diet pills Ponderax or Adifax?
  • Did you take them for more than 3 months?
  • If the answer to these questions is Yes: tell your doctor at your next visit as there is a small chance that these medications may have caused damage to your heart.

This leaflet contains important information for people who have taken diet pills called Ponderax or Adifax.

Ponderax and Adifax packaging.

It has recently been found that these diet pills, even if taken years ago, could have caused thickening of the heart valves in some people. In most cases the thickening is mild and does not cause any health problems. In a few people this valve thickening can prevent the heart valves from closing properly (known medically as mitral or aortic incompetence). If you think you may have taken either of these diet pills, it is important that you read this leaflet.

How can I tell if I took Ponderax or Adifax?

Ponderax and Adifax are diet pills that work by reducing the appetite. They were only available on a doctor’s prescription. Ponderax was marketed from 1966 to September 1997, Adifax from 1993 to September 1997. Neither medicine is now available. The following table contains more information to help you decide whether or not you have taken Ponderax or Adifax.

  Ponderax tablets Ponderax Pacaps Adifax capsules
Active ingredient Fenfluramine 20mg Fenfluramine 60mg Dexfenfluramine 15mg
Appearance Blister pack containing pale blue, rounded tablets with a shiny surface Blister pack containing capsules that were half blue and half clear, with tiny white beads inside Blister pack containing white capsules
Usual dose One tablet three times a day One capsule daily One capsule in the morning and one in the evening


Most of the diet pills available over the years have had a stimulant effect, which kept you awake. However, Ponderax and Adifax often caused drowsiness. If you have taken diet pills and you are not sure whether they were Ponderax or Adifax, your pharmacist or doctor may be able to help.

Do all diet pills cause heart valve abnormalities?

There are a number of other diet pills available in New Zealand, but only Ponderax and Adifax have been associated with heart valve problems.

What is my risk of developing a heart valve abnormality?

About 1 to 4% of normal, healthy people have a mild abnormality of the heart valves. From the limited information available, it appears that patients treated with Ponderax or Adifax for less than three months are not at any greater risk of heart valve abnormalities. However, those treated for 3 months or more (even if it was many years ago), do have an increased risk. From what is known, the risk of a serious problem is extremely low for most people. It is thought that the longer a person took Ponderax or Adifax, the higher their risk may be. In most cases the abnormality is mild, and has no effect on the person’s health.

What should I do if I have taken diet pills?

You do not need to see your doctor if you took Ponderax or Adifax for less than 3 months, or if you took other diet pills. If you are concerned, talk with your doctor at your next visit and ask for your heart to be examined.

If you have taken Ponderax or Adifax for 3 months or more, you will need to see your doctor to discuss the risks and for a heart examination. You do not need to make a special appointment to see your doctor straight away, but you should discuss this with your doctor at your next visit. However, if you have any worrying symptoms, such as breathlessness, palpitations (rapid or irregular heart beat) or ankle swelling, you should see your doctor straight away.

Your doctor has been given information about the risks of valve abnormalities and will know what to do. Here is what you can expect to happen:

  • The doctor will examine you for signs of heart problems. If any signs are found you will be referred to a cardiologist (heart specialist) for more tests.
  • The cardiologist will arrange a special test, called an echocardiogram, to examine your heart valves in detail. An echocardiogram involves bouncing sound waves off your heart, similar to the ultrasound examination used routinely on pregnant women.
  • The cardiologist will then be able to tell you if you have any valve abnormality and whether there are any precautions you need to take, such as taking antibiotics before dental and surgical procedures.

Should I be taking any special precautions?

People with thickened heart valves may need to take antibiotics before some types of dental and surgical procedures because they are at risk of developing an infection on the valve in the heart. If you have been examined and your doctor has found no evidence of a heart murmur or valve damage, you are at no higher risk of valve damage from infection than any other person. You do not need to take any special precautions.

If you need dental or other surgery and have not yet seen your doctor for a heart check, you will need to tell your dentist or surgeon that you took these diet pills. Your dentist or surgeon will know what to do.

ACC cover

It is possible that ACC will contribute to the cost of your visit to the doctor and perhaps also to further specialist treatment. Your doctor will give you an ACC claim form which will be sent to ACC for consideration.

More information on valvular abnormalities with dexfenfluramine and fenfluramine is in the Information for Health Professionals section

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