Polycythemia Vera



FREE PREVIEW Log in or buy this issue to read the full article. AAFP members and paid subscribers get free access to all articles. Subscribe now.


FREE PREVIEW Subscribe or buy this issue. AAFP members and paid subscribers get free access to all articles.

Am Fam Physician. 2004 May 1;69(9):2139-2144.

  Patient Information Handout

Polycythemia vera is a chronic myeloproliferative disorder characterized by increased red blood cell mass. The resultant hyperviscosity of the blood predisposes such patients to thrombosis. Polycythemia vera should be suspected in patients with elevated hemoglobin or hematocrit levels, splenomegaly, or portal venous thrombosis. Secondary causes of increased red blood cell mass (e.g., heavy smoking, chronic pulmonary disease, renal disease) are more common than polycythemia vera and must be excluded. Diagnosis is made using criteria developed by the Polycythemia Vera Study Group; major criteria include elevated red blood cell mass, normal oxygen saturation, and palpable splenomegaly. Untreated patients may survive for six to 18 months, whereas adequate treatment may extend life expectancy to more than 10 years. Treatment includes phlebotomy with the possible addition of myelosuppressive agents based on a risk-stratified approach. Agents under investigation include interferon alfa-2b, anagrelide, and aspirin. Consultation with a hematologist is recommended.

Polycythemia vera (PV) is a chronic myeloproliferative disorder characterized by an increased red blood cell mass (RCM), or erythrocytosis, which leads to hyperviscosity and an increased risk of thrombosis. Patients may present with complaints of pruritus after bathing, burning pains in the distal extremities (erythromelalgia), gastrointestinal disturbances, or nonspecific complaints such as weakness, headaches, or dizziness. Other patients are diagnosed after an incidental finding of an elevated hemoglobin and/or hematocrit level on a complete blood count.

The median age of patients diagnosed with PV is 60 years, although it can occur in persons in all age groups.1 PV occurs with a slight predominance in men. A comprehensive review1 reported the incidence of PV to be 2.3 per 100,000 persons per year. Therefore, a typical family physician can expect to make a diagnosis of PV once or twice during his or her career, and will often have at least one patient in his or her patient panel who carries the diagnosis. The seriousness of PV is underscored by the fact that the median survival in untreated symptomatic patients after diagnosis is six to 18 months.2 With treatment, the median survival is more than 10 years.2

Diagnosis

PV should be suspected when hemoglobin and/or hematocrit levels are elevated (i.e., hemoglobin level greater than 18 g per dL [180 g per L] in white men and 16 g per dL [160 g per L] in blacks and women; hematocrit level greater than 52 percent (0.52) in white men and 47 percent (0.47) in blacks and women).3  PV also should be suspected in patients with portal venous thrombosis and splenomegaly with or without thrombocytosis and leukocytosis. Other signs and symptoms are listed in Table 1.1,4

In making the diagnosis of PV, the physician must first exclude a secondary erythrocytosis.5,6  Once a secondary cause is ruled out (Table 27), the diagnosis of PV is made using a combination of major and minor criteria defined by the Polycythemia Vera Study Group (PVSG). Although new diagnostic modalities have been developed, these criteria remain the standard method to diagnose PV.8

Major diagnostic criteria include increased RCM, normal oxygen saturation, and the presence of splenomegaly. The test for RCM is a nuclear medicine study involving autologous infusion of radio-labeled red blood cells followed by serial phlebotomy to determine distribution. Physicians may refer patients to a specialty laboratory for this study.

TABLE 1

Signs and Symptoms of Polycythemia Vera

More Common

Hematocrit level > 52 percent (0.52) in white men, > 47 percent (0.47) in blacks and women

Hemoglobin level > 18 g per dL (180 g per L) in white men, > 16 g per dL (160 g per L) in blacks and women)

Plethora

Pruritus after bathing

Splenomegaly

Weight loss

Weakness

Sweating

Less Common

Bruising/epistaxis

Budd-Chiari syndrome

Erythromelalgia

Gout

Hemorrhagic events

Hepatomegaly

Ischemic digits

Thrombotic events

Transient neurologic complaints (headache, tinnitus, dizziness, blurred vision, paresthesias)

Atypical chest pain


Information from references 1 and 4.

TABLE 1   Signs and Symptoms of Polycythemia Vera

View Table

TABLE 1

Signs and Symptoms of Polycythemia Vera

More Common

Hematocrit level > 52 percent (0.52) in white men, > 47 percent (0.47) in blacks and women

Hemoglobin level > 18 g per dL (180 g per L) in white men, > 16 g per dL (160 g per L) in blacks and women)

Plethora

Pruritus after bathing

Splenomegaly

Weight loss

Weakness

Sweating

Less Common

Bruising/epistaxis

Budd-Chiari syndrome

Erythromelalgia

Gout

Hemorrhagic events

Hepatomegaly

Ischemic digits

Thrombotic events

Transient neurologic complaints (headache, tinnitus, dizziness, blurred vision, paresthesias)

Atypical chest pain


Information from references 1 and 4.

Changes to these diagnostic criteria have been proposed. For example, determinations of RCM, classically given in milliliters per kilogram (mL per kg), can be misleading if the patient is obese, because body fat is relatively avascular. The International Council for Standardization in Haematology (ICSH) has amended the RCM assessment, recommending the use of formulas incorporating body surface area, weight, gender, and plasma volume.810 [Level of evidence: C, consensus opinion] A patient with PV could have low oxygen saturation levels, because it is possible to have both PV and an unrelated hypoxic disorder.1 Palpable splenomegaly is an important physical finding and major criterion. However, palpation is only 58 percent sensitive for diagnosis11 (i.e., if present, it will not be detected by examiners in 42 percent of cases). Specificity is much better. This lack of sensitivity has led to some discussion about the use of imaging techniques to answer the question, although such a finding by imaging might be relegated to the status of a minor criterion.10 In addition, the minor criteria of leukocyte alkaline phosphatase (LAP) and serum vitamin B12 and B12 binding capacity may be dropped in the future because of inter-laboratory error regarding LAP and the unavailability of vitamin 10 B12 binding capacity. Furthermore, neither of these criteria is sensitive nor specific.1 Nonetheless, the PVSG criteria remain the diagnostic standard.

TABLE 2
Secondary Causes of Increased Red Cell Mass (Erythrocytosis)

The rightsholder did not grant rights to reproduce this item in electronic media. For the missing item, see the original print version of this publication.

Serum erythropoietin (EPO), bone marrow histopathology and karyotype, and the presence of endogenous erythroid colonies (EEC) have been proposed as diagnostic tests for PV. Because PV is an autonomous (i.e., EPO-independent) erythroid proliferation, serum EPO levels in PV are low or normal.1,5 Low-serum EPO levels for PV have a sensitivity of 70 percent and a specificity of 90 percent.1

Evaluation of Polycythemia Vera

FIGURE 1

Algorithm for the evaluation and management of polycythemia vera.

View Large

Evaluation of Polycythemia Vera


FIGURE 1

Algorithm for the evaluation and management of polycythemia vera.

Evaluation of Polycythemia Vera


FIGURE 1

Algorithm for the evaluation and management of polycythemia vera.

In PV, bone marrow displays characteristic histologic findings,10 and clonal cytogenetic abnormalities can be detected.5 Use of this test requires the availability of a histologist who is specially trained in marrow histology. Finally, EEC growth is based on the ability of erythroid cells from peripheral blood and bone marrow samples in PV to grow in vitro without the addition of EPO.12,13 This unique finding, along with serum EPO levels, forms the basis for a new diagnostic approach,5 but has the disadvantages of expense and limited availability.10

Although serum EPO levels and marrow biopsies may become a routine diagnostic option, the PVSG criteria remain the standard of diagnosis. Consultation with a hematologist is appropriate to aid in diagnosis, and serum EPO levels and bone marrow biopsy should be considered if available. An algorithm summarizing the evaluation and management of PV is presented in Figure 1.

Treatment

No single treatment is available for PV. Thrombosis accounts for the majority of morbidity and mortality. The major goal of treatment is to prevent thrombotic events. Examples of thrombotic events include arterial and venous thrombosis, cerebrovascular accident, deep venous thrombosis, myocardial infarction, peripheral arterial occlusion, and pulmonary infarct.14  Of additional importance to the family physician is the symptomatic treatment of the bothersome microvascular sequelae, such as pruritus and distal extremity erythromelalgia (Table 31,1517). Because PV is a rare condition, it has been difficult to assemble patients for well-designed, randomized controlled trials with long- term follow-up. Therefore, recommendations for treatment are based on lower quality evidence from case series and uncontrolled trials.

TABLE 3

Symptomatic Treatments in Polycythemia Vera

Symptom Treatment Level of evidence

Pruritus

H1 and H2 blocking antihistamines15 (diphenhydramine [Benadryl], cyproheptadine [Periactin], hydroxyzine [Atarax, Vistaril], fexofenadine [Allegra], terfenadine [Seldane])

C

Paroxetine15 (Paxil)

C

Oatmeal or starch baths (in lukewarm water)16

C

Recombinant interferon alfa-2b (Intron A)1

C

Erythromelalgia

Aspirin, 50 to 100 mg daily17

C

Myelosuppressive agents17

C


Information from references1, and1517.

TABLE 3   Symptomatic Treatments in Polycythemia Vera

View Table

TABLE 3

Symptomatic Treatments in Polycythemia Vera

Symptom Treatment Level of evidence

Pruritus

H1 and H2 blocking antihistamines15 (diphenhydramine [Benadryl], cyproheptadine [Periactin], hydroxyzine [Atarax, Vistaril], fexofenadine [Allegra], terfenadine [Seldane])

C

Paroxetine15 (Paxil)

C

Oatmeal or starch baths (in lukewarm water)16

C

Recombinant interferon alfa-2b (Intron A)1

C

Erythromelalgia

Aspirin, 50 to 100 mg daily17

C

Myelosuppressive agents17

C


Information from references1, and1517.

The PVSG and Gruppo Italiano Studio Policitemia (GISP) are two prospective trials that have unearthed a therapeutic dilemma regarding the two basic treatment approaches—phlebotomy alone and phlebotomy plus myelosuppressive agents. A number of new therapeutic agents have been developed. In addition to interferon alfa-2b (Intron A) therapy, agents that target platelet number (e.g., anagrelide [Agrylin]), and platelet function (e.g., aspirin) are being investigated as potential therapies.

TABLE 4

Myelosuppressive Agents for the Treatment of Polycythemia Vera

Agent Class Common side effects Uncommon side effects Precautions

Hydroxyurea (Hydrea)

Antimetabolite

Anemia, neutropenia, oral ulcers, skin ulcers, hyperpigmentation, nail changes

Leg ulcers, nausea, diarrhea, fever, elevated liver function test results

Renal disease

Recombinant interferon alfa-2b (Intron A)

Myelosuppressive

Influenza-like symptoms, fatigue, anorexia, weight loss, alopecia, headache, nausea, insomnia, body pain

Confusion, depression, autoimmunity, hyperlipidemia

Psychiatric disease, cardiovascular disease

Radioactive phosphorus (32P)

Radiopharmaceutical

Anemia, thrombocytopenia, leukopenia, Leukemia may develop after treatment

Diarrhea, fever, nausea, emesis

Busulfan (Myleran)

Alkylating agent

Pancytopenia, hyperpigmentation, ovarian suppression

Pulmonary fibrosis, leukemia, seizure, hepatic veno-occlusion

Seizure disorder


Adapted with permission from Tefferi A. Polycythemia vera: a comprehensive review and clinical recommendations. Mayo Clin Proc 2003;78:184, with additional information from references26 and27.

TABLE 4   Myelosuppressive Agents for the Treatment of Polycythemia Vera

View Table

TABLE 4

Myelosuppressive Agents for the Treatment of Polycythemia Vera

Agent Class Common side effects Uncommon side effects Precautions

Hydroxyurea (Hydrea)

Antimetabolite

Anemia, neutropenia, oral ulcers, skin ulcers, hyperpigmentation, nail changes

Leg ulcers, nausea, diarrhea, fever, elevated liver function test results

Renal disease

Recombinant interferon alfa-2b (Intron A)

Myelosuppressive

Influenza-like symptoms, fatigue, anorexia, weight loss, alopecia, headache, nausea, insomnia, body pain

Confusion, depression, autoimmunity, hyperlipidemia

Psychiatric disease, cardiovascular disease

Radioactive phosphorus (32P)

Radiopharmaceutical

Anemia, thrombocytopenia, leukopenia, Leukemia may develop after treatment

Diarrhea, fever, nausea, emesis

Busulfan (Myleran)

Alkylating agent

Pancytopenia, hyperpigmentation, ovarian suppression

Pulmonary fibrosis, leukemia, seizure, hepatic veno-occlusion

Seizure disorder


Adapted with permission from Tefferi A. Polycythemia vera: a comprehensive review and clinical recommendations. Mayo Clin Proc 2003;78:184, with additional information from references26 and27.

The mainstay of treatment for PV is phlebotomy, which is aimed at reducing hyperviscosity by decreasing the venous hematocrit level to less than 45 percent (0.45) in white men and 42 percent (0.42) in blacks and women.1,14,18 The PVSG reported the best median survival, 12.6 years, for this type of treatment.14 Some features of using phlebotomy alone are attractive, primarily because it is a simple procedure without many risks, except for the eventual development of iron deficiency.8 Some experts have cast doubt on the PVSG findings regarding median survival, noting that up to 50 percent of patients treated with phlebotomy alone had to switch to other treatments by the fifth year.19 The PVSG found a statistically significant increase in the number of thrombotic events within the first three years of initiating treatment, compared with the use of myelosuppressive agents.14 After this period, however, the rate of thrombosis remained the same for both treatment approaches. Furthermore, the GISP found an added independent dimension to the risk of thrombosis—rates increase with age and a history of thrombotic events.20 Despite these concerns, a recent survey of physicians who were members of the American Society of Hematology showed that 69 percent use phlebotomy as first-line therapy for PV.21

TABLE 5

Risk Stratification in Polycythemia Vera

Risk category Risk factors

Low risk

Age younger than 60 years

and

No history of thrombocytosis

and

Platelet count lower than 150,000 per mm3 (1,500 × 109 per L)

Indeterminate risk

Age younger than 60 years

and

No history of thrombocytosis

and either

Platelet count higher than 150,000 per mm3

or

Presence of cardiovascular risk actors

High risk

Age 60 years or older

or

Positive history of thrombosis


Adapted with permission from Tefferi A. Polycythemia vera: a comprehensive review and clinical recommendations. Mayo Clin Proc 2003;78:184.

TABLE 5   Risk Stratification in Polycythemia Vera

View Table

TABLE 5

Risk Stratification in Polycythemia Vera

Risk category Risk factors

Low risk

Age younger than 60 years

and

No history of thrombocytosis

and

Platelet count lower than 150,000 per mm3 (1,500 × 109 per L)

Indeterminate risk

Age younger than 60 years

and

No history of thrombocytosis

and either

Platelet count higher than 150,000 per mm3

or

Presence of cardiovascular risk actors

High risk

Age 60 years or older

or

Positive history of thrombosis


Adapted with permission from Tefferi A. Polycythemia vera: a comprehensive review and clinical recommendations. Mayo Clin Proc 2003;78:184.

The use of myelosuppressive agents such as radioactive phosphorus (32P), chlorambucil (Leukeran), busulfan (Myleran), pipobroman (Vercyte), and hydroxyurea (Hydrea) in conjunction with phlebotomy has been studied. Chlorambucil, busulfan, and pipobroman, all alkylating agents, have fallen out of favor because of concerns about rates of iatrogenic leukemia.19 The agent 32P remains in use with supplemental phlebotomy and has a reported median survival similar to that of phlebotomy alone—10.9 years according to PVSG data14 and 11.8 years according to GISP.20 The myelosuppressive drugs such as 32P had an initial advantage over phlebotomy alone regarding thrombosis rates during the first three years of treatment. However, this effect disappeared after three years, and rates of thrombosis thereafter were equivalent.8,14,19 Unfortunately, prospective data have revealed the mutagenic potential of myelosuppressive agents such as 32P, with a relative risk for malignancy of 2.3 to four times that of the control groups after about six years of treatment. Patients treated with phlebotomy alone had the same rate of cancer as patients in the control groups.2,14,20

The nonalkylating myelosuppressive agent hydroxyurea is widely used in the treatment of PV, because it is less leukemogenic.22 PVSG data have established this agent to be an effective bone marrow suppressant. Hydroxyurea is associated with a lower risk of thrombosis compared with solely phlebotomized patients. Concern regarding the safety of long-term use of hydroxyurea has been noted.14,19

Recombinant interferon alfa-2b reduces myeloproliferation and splenomegaly, and alleviates the symptom of pruritus.23 It has no established mutagenic potential, and thus may prove a valuable option for younger patients and those with impressive splenomegaly.19 A small case series of 11 patients found that the patients’ red cell indices could be normalized over six to 12 months with interferon therapy alone, and without evidence of thrombosis.24 However, many patients discontinue interferon because of side effects, and the cost of treatment is high.23,25  Myelosuppressive treatment options are summarized in Table 4.1,26,27

Reduction of platelet counts with anagrelide has been proposed as a treatment option for PV, as with other myeloproliferative disorders, but this option has not been thoroughly studied.19,25 Targeting platelet function with aspirin remains another possibility. One PVSG protocol found that 300 mg of aspirin daily in conjunction with phlebotomy and dipyridamole (Persantine) was associated with an increased risk of gastrointestinal bleeding.14 However, a small GISP study randomized patients to low-dose aspirin (40 mg per day) or placebo and found no increased rates of bleeding or complications.1 The use of low-dose aspirin is being investigated by the European Collaboration on Low-Dose Aspirin.19,22,25

A risk-stratified approach to the management of PV is currently recommended (Table 5).1 [Level of evidence: C, expert opinion] Patients treated with phlebotomy alone benefit from low rates of malignancy but experience more thrombosis events during the first few years of treatment. Patients treated with myelosuppressive agents and supplemental phlebotomy avoid this early thrombotic risk but in turn have significant rates of malignant transformation after about six years of therapy. Therefore, stratifying patients by age and risk of thrombosis is useful. High-risk patients are those 60 years or older, or those with a history of thrombosis. A myelosuppressive agent with supplemental phlebotomy is reasonable in this group. This group’s generally shorter life expectancy lessens the threat of eventual iatrogenic malignancy. Patients in this group stand to gain from the benefit of lower early thrombosis rates with myelosuppressive medications. Those considered at indeterminate risk are younger than 60 years and have no history of thrombocytosis, but do have cardiovascular or other risk factors.1 Therapy in this group should be individualized, possibly with the addition of agents acting on platelet function or number. Finally, those considered low risk are younger than 60 years and have no thrombosis-related risk factors. Phlebotomy alone may be the treatment of choice with the goal of reducing the hematocrit level to less than 45 percent (0.45) or lower based on gender and race.1,14,19,25 Consultation with a hematologist is recommended to apply such strategies, and newer agents may be tailored to patients on an individualized basis.

PV produces microvascular sequelae whose symptoms, while not life threatening, can be bothersome to patients (Table 1).1,4  Because PV is rare, high-quality evidence supporting treatment is lacking. Pruritus, particularly after bathing (aquagenic pruritus) is a common symptom and various treatment options are available (Table 31,1517). Symptoms such as transient neurologic disturbances may respond to low-dose aspirin therapy. Erythromelalgia is rare, occurring in approximately 3 percent of patients with PV. Low-dose aspirin typically is used, with myelosuppressive therapy reserved for those patients who do not respond.1

The Authors

BRIAN J. STUART, LT, MC, USNR, is serving with the Second Medical Battalion, Second Flight Support Group, Group Aid Station, at Camp Lejune, N.C. He received his medical degree from Saint Louis University School of Medicine, St. Louis, and completed his residency in family medicine at Naval Hospital Jacksonville, Jacksonville, Fla.

ANTHONY J. VIERA, LCDR, MC, USNR, is a staff family physician at Naval Hospital Jacksonville, and assistant professor of family medicine at the Uniformed Services University of the Health Sciences F. Edward Hébert School of Medicine, Bethesda, Md. He received his medical degree from the Medical University of South Carolina College of Medicine, Charleston, and completed a residency in family medicine at Naval Hospital Jacksonville.

Address correspondence to Brian J. Stuart, M.D., Naval Hospital Jacksonville, Family Practice Department, 2080 Child St., Jacksonville, FL 32214 (e-mail: stuartbj@2fssg.usmc.mil). Reprints are not available from the authors.

The authors indicate that they do not have any conflicts of interest. Sources of funding: none reported.

The opinions and assertions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views of the U.S. Navy Medical Corps or the U.S. Navy at large.

REFERENCES

1. Tefferi A. Polycythemia vera: a comprehensive review and clinical recommendations. Mayo Clin Proc. 2003;78:174–94.

2. Berk PD, Goldberg JD, Donovan PB, Fruchtman SM, Berlin NI, Wasserman LR. Therapeutic recommendations in polycythemia vera based on Polycythemia Vera Study Group protocols. Semin Hematol. 1986;23:132–43.

3. Lamy T, Devillers A, Bernard M, Moisan A, Grulois I, Drenou B, et al. Inapparent polycythemia vera: an unrecognized diagnosis. Am J Med. 1997;102:14–20.

4. Hoffman R. Hematology: basic principles and practice. 3d ed. New York: Churchill Livingstone, 2000:1130–55.

5. Tefferi A. Diagnosing polycythemia vera: a paradigm shift. Mayo Clin Proc. 1999;74:159–62.

6. Murphy S. Diagnostic criteria and prognosis in polycythemia vera and essential thrombocythemia. Semin Hematol. 1999;36(1 Suppl 2):9–13.

7. Polycythemia: primary and secondary. In: Kjeldsberg CR. Practical diagnosis of hematologic disorders. 3d ed. Chicago: ASCP Press, 2000:121.

8. Berlin NI. Polycythemia vera: diagnosis and treatment 2002. Expert Rev Anti-cancer Ther. 2002;2:330–6.

9. Pearson TC, Guthrie DL, Simpson J, Chinn S, Barosi G, Ferrant A, et al. Interpretation of measured red cell mass and plasma volume in adults: Expert Panel on Radionuclides of the International Council for Standardization in Haematology. Br J Haematol. 1995;89:748–56.

10. Pearson TC. Evaluation of diagnostic criteria in polycythemia vera. Semin Hematol. 2001;38(1 Suppl 2):21–4.

11. Grover SA, Barkun AN, Sackett DL. The rational clinical examination. Does this patient have splenomegaly?. JAMA. 1993;270:2218–21.

12. Weinberg RS, Worsley A, Gilbert HS, Cuttner J, Berk PD, Alter BP. Comparison of erythroid progenitor cell growth in vitro in polycythemia vera and chronic myelogenous leukemia: only polycythemia vera has endogenous colonies. Leuk Res. 1989;13:331–8.

13. Michiels JJ, Juvonen E. Proposal for revised diagnostic criteria of essential thrombocythemia and polycythemia vera by the thrombocythemia vera study group. Semin Thromb Hemost. 1997;23:339–47.

14. Berk PD, Wasserman LR, Fruchtman SM, Goldberg JD. Treatment of polycythemia vera: a summary of clinical trials conducted by the polycythemia vera study group. In: Wasserman LR, Berk PD, Berlin NI, eds. Polycythemia vera and the myeloproliferative disorders. Philadelphia: W.B. Saunders, 1995:166–94.

15. Diehn F, Tefferi A. Pruritus in polycythaemia vera: prevalence, laboratory correlates and management. Br J Haemat. 2001;115:619–21.

16. Fruchtman SM, Wasserman LR. Therapeutic recommendations for polycythemia vera. In: Wasserman LR, Berk PD, Berlin NI, eds. Polycythemia vera and the myeloproliferative disorders. Philadelphia: W.B. Saunders, 1995:337.

17. Michiels JJ. Erythromelalgia and vascular complications in polycythemia vera. Semin Thromb Hemost. 1997;23:441–54.

18. Gilbert HS. Current management in polycythemia vera. Semin Hematol. 2001;38(1 Suppl 2):25–8.

19. Barbui T, Finazzi G. Treatment of polycythemia vera. Haematologica. 1998;83:143–9.

20. Polycythemia vera: the natural history of 1213 patients followed for 20 Years. Gruppo Italiano Studio Policitemia. Ann Intern Med. 1995;123:656–64.

21. Streiff MB, Smith B, Spivak JL. The diagnosis and management of polycythemia vera in the era since the Polycythemia Vera Study Group: a survey of American Society of Hematology members’ practice patterns. Blood. 2002;99:1144–9.

22. Michiels JJ, Barbui T, Finazzi G, Fuchtman SM, Kutti J, Rain JD, et al. Diagnosis and treatment of polycythemia vera and possible future study designs of the PVSG. Leuk Lymphoma. 2000;36:239–53.

23. Lengfelder E, Berger U, Hehlmann R. Interferon alpha in the treatment of polycythemia vera. Ann Hematol. 2000;79:103–9.

24. Silver RT. Interferon alpha-2b: a new treatment for polycythemia vera. Ann Intern Med. 1993;119:1091–2.

25. Solberg LA Jr. Therapeutic options for essential thrombocythemia and polycythemia vera. Semin Oncol. 2002;29(3 Suppl 10):10–5.

26. Physician’s desk reference. 58th ed. Montvale, N.J.: Thomson PDR, 2004.

27. Klasco RK, ed. USP DI drug information for the healthcare professional. Greenwood Village, Colo.: Thomson Micromedex, 2004.

Members of various family medicine departments develop articles for “Practical Therapeutics.” This article is one in a series coordinated by the Department of Family Medicine at Naval Hospital Jacksonville, Jacksonville, Fla. Guest editor of the series is Anthony J. Viera, LCDR, MC, USNR.



Copyright © 2004 by the American Academy of Family Physicians.
This content is owned by the AAFP. A person viewing it online may make one printout of the material and may use that printout only for his or her personal, non-commercial reference. This material may not otherwise be downloaded, copied, printed, stored, transmitted or reproduced in any medium, whether now known or later invented, except as authorized in writing by the AAFP. Contact afpserv@aafp.org for copyright questions and/or permission requests.

Want to use this article elsewhere? Get Permissions


Article Tools

  • Download PDF
  • Print page
  • Share this page
  • AFP CME Quiz

Information From Industry

More in AFP

More in Pubmed

Navigate this Article