The Effect of Dexamethasone on Platelet Function K. M. LICHTENFELD AND C. A. SCHIFFER From the Cell Component Therapy Section. Clinicul Oncology Brunch, National Cancer Institute, Baltimore Cancer Research Center, University of Maryland Hospital, Baltimore, Maryland

To assess the effects of dexamethasone on platelet lunction, aggregation studies were performed on nine healthy adults before and after ingestion of a single dose of dexamethasone 10 mg, and on six patients receiving daily dexamethnsone. Bleeding times were done on 14 volunteers before and after a similar drug dosc. Platelet aggregation by ADP, epinephrine and collagen was unchanged after dexamethasonein the healthy subjects and aggregation curves in the patient group were comparable to the normals. Bleeding times were moderately probnged in women (from 284 ? 58 seconds to 389 5 114 seconds) but not in men. This prolongation was much kss pronounced than that whieh occurs with low doses of aspirin and no subject experienced delayed bleeding. Dexamethepone in single high doses probably does not cause a clinically important effect on platelet function.

DEXAMETHASONE is widely used clinically for the treatment of cerebral edema,6collagen vascular diseases, allergic conditions and many hematologic and neoplastic disorders. Recently, the drug has been given to normal donors to increase the yield of granulocytes for transfusion into leukopenic patientss Dexamethasone is chosen specifically because it is potent, long-acting, may be given orally, and has a minimum of mineralocorticoid effect.' It is used in granulocyte collection because there appears to be no impairment of neutrophil accumulation at inflammatory sites as may occur when prednisone is used.I5 Although there have been several studies evaluating the effects of various corticosteroids on g r a n u l o ~ y t e s , ~there J ~ is little information regarding platelet function following steroid ingestion. Many patients receiving steroids are also treated with drugs that suppress the platelet count or interfere with platelet aggregation. Since recipients of granulocyte transfusion are usually thromboReceived for publication January 26, 1978; accepted March 5, 1978.

cytopenic and because they receive large numbers of platelets that are harvested with the white blood cells, any alteration of platelet aggregation by drugs may have adverse clinical effect^.^ Similarly steroids have been associated with gastrointestinal ulceration and bleeding,4 situations in which normal platelet function is important for hemostasis. Because of these important clinical correlates, we evaluated the effect of dexamethasone on in vitro and in vivo platelet function in healthy adults given a single high dose, and in patients with brain tumors receiving chronic doses of dexamethasone. Materials and Methods Baseline platelet aggregation studies and platelet counts were performed on nine healthy adults (six men, three women), four of whom were granulocyte donors. No subject had taken drugs known to affect platelet function for at least seven days except for one woman who took a single dose of chlorpheniramine maleate five days prior to study. Each subject received dexamethasone (Hexadrol,@ Organon, Inc., West Orange, NJ) 10 mg orally and aggregation studies and platelet counts were repeated 10 to 12 hours later. This time span was selected because it has been convenient to administer the drug orally to granulocyte donors the night prior to the morning of leukapharesis. In addition, before and after dexamethasone bleeding times were done on 14 volunteers (seven men, seven women, ages 20-41). Each person served as his own control. Informed consent was obtained from each volunteer. Platelet aggregation was also evaluated in six patients with advanced astrocytomas who were taking total daily doses of dexamethasone ranging from two to 64 mg for periods of one week (one patient) to 18 months. All had undergone surgery and radiation therapy and only one had received prior chemotherapy.

0041-1 132/79/0300/0169 $00.70 8 J. B. Lippincott Co. Transfusion

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Blood for aggregation was obtained by venipuncture with a plastic syringe and mixed in plastic tubes in a 9: 1 proportion with 3.8 per cent sodium citrate. Platelet-rich plasma (PRP) was prepared by centrifugingthe blood at 1900 x g for five minutes. Platelet poor plasma was obtained by spinning PRP at 4ooo x g for 10 minutes. Platelets were maintained at room temperature for 30 to 60 minutes and were then placed at 37 C in the aggregometer cuvettes at least five minutes prior to the addition of aggregating agents. All experiments were performed within two hours of collection. Platelet aggregation was performed in a model PAP-2 aggregometer (Bio Data Corporation, Willow Grove, Pennsylvania), using ADP (20 p M , 1 p M , .5 pM final concentrations) pinephrine (100 p M ,50 pM)and collagen (.026 p M ) as aggregating agents (Par/ pack, Bio-Data Corporation). Aggregation curves were analyzed by measuring the maximum increase in light transmission three minutes after addition of ADP and eight mimites after adding collagen or epinephrine. The curves obtained following dexamethasone administration were compared with the corresponding baseline for each subject. Data from brain tumor patients were compared with the prcdexamethasone curves of the healthy controls. Platelet counts were determined electronically using a Coulter Thrombocounter (Coulter Electronics, Hialeah, Florida). Bleeding times were performed using a modification of the template technique.’* Two incisions were made simultaneously and the bleeding times were averaged. Statistical analyses were performed using the Student’s t-test for paired observations.

Results Platelet Counts

There were no significant changes in platelet counts after dexamethasone administration in the normal subjects. Brain tumor patients had normal platelet counts (252,000 to 307,000/pl) at the time of the aggregation studies.

ADP employed. With collagen, there was no significant difference in the time required for initiation of aggregation before and after steroid. Aggregation curves of the six brain tumor patients using 20 p M and 0.5 p M ADP and 0.026 gM collagen were similar in shape and in maximum light transmission when compared with predexamethasone curves from the normal subjects. Bleeding Times

The mean baseline bleeding time for 14 normal subjects was 264 ~t62 seconds (SD), which is comparable to the 270 f 100 seconds determined in 100 normal subjects by Harker and Slichter.’ The mean difference in bleeding time between the duplicate incisions in our subjects was 29 seconds. The mean postdexamethasone bleeding time for the group was 329 2 107 seconds (SD) which is statistically significantly different from control values (p < .05). When men and women were analyzed separately, it was found that the difference was accounted for by slenificant prolongation of postdexamethasone bleeding times in the women only (Table 1). Men had before and after drug bleeding times of 244 2 59 seconds and 268 r 59 seconds respectively which are not significantly different. Predexamethasone bleeding times were similar in both sexes. Mean body surface areas were 1.9 m* for men and 1.7 m2for women, suggesting that the in vivo concentrations of dexamethasone was similar for both groups. After a careful review of subject histories, it was ascertained that the women ingested more drugs than did the men. One subject, who took oral contraceptives and had used trimethoprinsulfamethoxazole four days prior to study had a postdexamethasone bleeding time prolongation of 348 seconds. Although the antibiotic combination has caused occasional cases of thrombocytopenia.5 its effect on bleeding time and its possible Table 1. Bleeding Times Before end After Ingestion of Dexamethasone PredexaPostdexamethasone methasone Bleeding Time Bleeding Time (sec)’ (sec)’ Number

Aggregation

In nine normal subjects, there were no significant alterations in the aggregation curves after dexamethasone when control curves were compared for ADP, epinephrine, and collagen. Of eight subjects who exhibited secondary waves of aggregation with 50 p M epinephrine before dexamethasone, only one subject demonstrated inhibition of the secondary wave after receiving the drug. No secondary waves were demonstrated in the controls with the lower concentrations of

Female

7

284 2 58 (238-405)

389 f 114 (269-586)

Male

7

244 2 64 (180-371)

268 f 59 (177-345)

Total

14

264 ? 62

329 f 107

Mean f SD, ranges in parentheses.

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DEXAMETHASONE AND PLATELETS

interaction with steroids and/or oral contraceptives is not known. Some oral contraceptives have been associated with enhancementof platelet aggregation16but effects on bleeding time have not been reported. Another woman had taken two doses of antihistamine six and five days before the study. Although this drug may inhibit ADP-induced aggregati~n,'~this subject had normal aggregation and a postdexamethasone bleeding time only 60 seconds longer than her control. One woman who took oral contraceptives also had normal aggregation and a postdexamethasone bleeding time prolongation of 80 seconds. Another subject taking low-dose tetracycline bled 35 seconds longer after the steroid. Discussion Dexamethasone in single pharmacologic doses did not inhibit in vitru platelet aggregation in normal individuals. Similarly patients receiving chronic large doses of dexamethasone had aggregation curves comparable to the normal controls. Although there have been many references to the role of steroids in disease states in which platelets may be involved (transplant rejection, thrombotic thrombocytopenic purpura, and endotoxin shock)I3 there are few studies in humans describing the effect of steroids on the platelet per se. Inhibition of platelet aggregation by glucocorticoids has been previously sugge~ted.~*l'.l~ In two methylprednisolone incubated with washed platelets in vitru was shown to act directly on the platelet membrane thereby altering aggregation by ADP, thrombin, epinephrine, and collagen. In addition, Cazenave and coworkers2 infused platelets treated in vitru with high doses of methylprednisolone into thrombocytopenic rabbits and noted prolongation of the jugular vein bleeding time when compared to control animals. They suggested that high doses of steroids prevent platelets from reacting to injured vessels. In contrast, there are anecdotal reports as well as other data suggesting that steroids may actually ameliorate bleeding in thrombocytopenic states possibly by affecting vascular membranes. Kitchens et a/.10noted that the morphologic abnormalities of capil-

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lary endothelium in thrombocytopenic rabbits were not seen in animals treated with showed that oral prednisone. Mant et high dose prednisone (80 mg daily x 2 doses) did not prolong bleeding times of normal human volunteers while in our study, using high doses of dexamethasone, there was no inhibition of aggregation in response to collagen or other reagents. The varying results and multiple proposed mechanisms of action of steroids in the above studies demonstrate the problems of comparing different glucocorticoids particularly when different species and test systems are used. Although female subjects as a group had a mean increase in bleeding time of 114 seconds after a relatively high dose of dexamethasone, this is not as pronounced as the mean increase of 4.5 minutes that occurs with low doses of aspirin.$ It is unknown whether the prolongation in this group was a result of possible interactions between female sex hormones and/or the other drugs being taken with the steroid. Also, the interaction of these substances with platelets, blood vessels or the reaction between platelets and endothelid surfaces is not clear. Lack of prolongation of bleeding times in men suggests that the drug probably does not produce clinically significant alteration in platelet-related hemostasis. No subject experienced delayed bleeding from incision sites or in other areas. Normal aggregation curves in the patients receiving chronic dexamethasone indicates that there is probably no clinically important dexamethasonerelated effect on platelets that would interfere with other modalities of therapy such as radiation, surgery, or chemotherapy. Similarly, in white blood cell donors, a single dose of dexamethasone does not alter in v i m platelet function in the donor. In our experience transfused platelets collected from donors receiving dexamethasone seem to function normally hemostatically and demonstrate normal survival curves.18Dexamethasone therefore would appear to be an acceptable agent for donor premedication.

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Acknowledgment The authors gratefully acknowledge the technical assistance of Ms. Virginia Young and Ms. Theda Strohecker.

References

on thrombocytopenic bleeding and its prevention by prednisone. Clin. Res. 24:17A. 1976. 1 I. Mant, M.J., K. L. Thong, and M. G. Grace: Effect of prednisone on normal and post-aspinn bleeding time and platelet function. Clin. Res. 2J: 627A. 1975. 12. Mielke, C. H., Jr., M.M.Kaneshiro, I. A. Maher, J. M. Weiner, and S. I. Rappaport:The standard-

1. Axelrod. L.: Glucocorticoid therapy. Medicine 55:

39, 1976. 2. Caeenave, J-P., J. A. Davies. A. F. Senyi, M. A.

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dlajchman, J. Hirsch, and J. F. Mustard: Effects of methylprednisolone on platelet adhesion to damaged aorta, bleeding time and platelet survival. Blood &1009, 1976. DeGaetano. G.,M. B. Donati, and S. Garattini: Dmgs aecting platelet function tests. Thrombos. Diathes. Haemorr. 34:285. 1975. Fauci, A. S., D. C. Dale, and J. E. Balow: Glucocorticosteroid therapy: mechanisms of action and clinical considerations. Anti. Intern. Med. 84.304. 1976. Frisch, J. M.: Clinical experience with adverse reactions to trimethoprim-sulfamethoxazole. J. Infect. Dis. 128Suppl. 607, 1973. Gutin, P. H.: Corticosteroid therapy in patients with cerebral tumors: benefits, mechanisms, problems, practicalities. Sem. Oncol. 2:49, 1975. Harker, L. A.. and S. J. Slichter: The bleeding time as a screening test for evaluation of platelet function. N. Engl. I. Med. 282155, 1972. Higby, D. J., J. M. Mishler, W. Rhomberg, R. W. Nicora, and J. F. Holland: The effect of a single or double dose of dexamethasone on granulocyte collection with the continuous flow centrifuge. Vox Sang. 2ik243, 1975. Kasper. C. K..and S. 1. Rappaport: Bleeding times and platelet aggregation after analgesics in hemophilia. Ann. Intern. Med. 77:189, 1972. Kitchens, C. S., L. Weiss, and L. E. Cluff: Studies

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ized normal Ivy bleeding time and its prolongation by aspirin. Blood 34:204, 1969. Mustard, J. F.. and M. A. Packham: Factors influencing platelet function: adhesion, release and aggregation. Pharmacol. Rev. 2297, 1970. Packham, M. A., E. E. Nishizawa, and J. F. Mustard: Response of platelets to tissue injury. Biochem. Pharmacol. 22Suppl. 171. 1968. Peters, W. P., J. F. Holland, H.Senn, W. Rhomberg, and T. Banerjee: Corticosteroid administration and localized leukocyte mobilization in man. N. Engl. J. Med. 286:342, 1972. Poller, L., J. M. Thomson, P. W. Thomas, and C. Wray: Blood clotting and platelet aggregation during oral progestogen contraception. Br. Med. J. 1:705, 1971. Sanders, W. J., IV, A. Rosenberg. and J. Hawiger: Human platelet function under influence of methylprednisolone: Inhibition of aggregation. serotonin release, and clot-promoting phospholipid irrespective of membrane receptors involved. Clin. Res. 24:48A. 1976. Schiffer, C. A. unpublished observations.

Karen M. Lichtenfeld, M.D.,Investigator, Baltimore Cancer Research Center, University of Maryland Hospital, 22 S. Greene Street, Baltimore, Maryland 21201.

Charles A. Schiffer, M.D., Head, Cell Component Therapy Section, Baltimore Cancer Research Center (reprint requests).

The effect of dexamethasone on platelet function.

The Effect of Dexamethasone on Platelet Function K. M. LICHTENFELD AND C. A. SCHIFFER From the Cell Component Therapy Section. Clinicul Oncology Brunc...
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