CMAJ/JAMC Letters
Correspondance

 

Debate over dexfenfluramine

CMAJ 1997;157:14
See response by: S.R. Sukkari
See also:
  • Letter: Drug to treat obesity: editorial writer responds, G.A. Faich
In her letter "Weighing benefits and risks of drug to treat obesity" (CMAJ 1997;156:768-9 [full text; response: Servier Canada]), Sana R. Sukkari reiterates the risk of primary pulmonary hypertension (PPH) that may result from long-term use of appetite suppressant drugs, reported in the epidemiologic study by Abenhaim and associates.1 This study compared the intake of appetite suppressants for more than 3 months in 4 countries in patients with PPH and in control subjects matched by age and sex. It found a 23-fold higher incidence of PPH in the patients who took the appetite suppressants than in the controls; this translates into 23 to 46 cases of PPH per 1 000 000 adults per year.2

However, the study did not control for body mass index. Although the actual weights of the subjects and controls were not reported, it was noted that the subjects were, on average, 1.6 times heavier than the controls.

Obese people have a high incidence of snoring and obstructive sleep apnea (due to adipose occlusions of the pharynx), inducing pulmonary vasoconstriction.3,4 PPH is an accompaniment of the hypoxemia­hypercapnea of apnea.5­8 Significantly obese patients are more likely than others to have taken a fenfluramine, particularly for a long period of time, because of the intransigence of their obesity; however, the population of significantly obese patients already has an increased incidence of PPH.

Thus, to confirm an increased incidence of PPH resulting from fenfluramine or dexfenfluramine, the control subjects would have to be matched obese people who had never received the drugs.

Mervyn Deitel, MD
Toronto, Ont.

References

  1. Abenhaim L, Moride Y, Brenot F, Rich S, Benichour J, Kurz X, et al. Appetite
    suppressant drugs and the risk of primary pulmonary hypertension. N Engl J Med 1996;335:609-16.
  2. Deitel M. Appetite suppressant drugs and the risk of primary pulmonary hypertension [editorial]. Obes Surg 1997;7:3-4.
  3. Koskenvuo M, Partinen M, Kaprio J, Vuorinen H, Telakivi T, Kajaste S, et al. Snoring and cardiovascular risk factors. Ann Med 1994;24:371-6.
  4. Shahi B, Praglowski B, Deitel M. Sleep-related disorders in the obese. Obes Surg 1992;2:157-68.
  5. Sugerman HL, Baron PL, Fairman RP, Evans CR, Vetrovec GW. Hemodynamic dysfunction in obesity-hypoventilation syndrome and the effects of treatment with surgically induced weight loss. Ann Surg 1988;207:604-13.
  6. Herrera M, Deitel M. Cardiac function in massively obese patients and the effect of weight loss. Can J Surg 1991;34:431-4.
  7. Davidson WR. Ventricular hypertrophy in sleep apnea. J Sleep Res 1995;4(suppl 1):176-81.
  8. Kessler R, Chaouat A, Weitzenblum E, Oswald M, Ehrhart M, Apprill M, et al. Pulmonary hypertension in the obstructive sleep apnoea syndrome: prevalence, causes and therapeutic consequences. Eur Respir J 1996;9:787-94.

Comments Send a letter to the editor responding to this letter
Envoyez une lettre à la rédaction au sujet de cette lettre
| CMAJ July 1, 1997 (vol 157, no 1) / JAMC le 1er juillet 1997 (vol 157, no 1) |