To Name :
To Email :
From Name :
From Email :
Comments :

Pearls


How plasma donation can affect your patient’s pharmacotherapy

Vol. 11, No. 05 / May 2012

Discuss this article at www.facebook.com/CurrentPsychiatry

Many economically disadvantaged psychiatric patients donate plasma for financial incentive. However, plasmapheresis (PP)—separation of plasma and cellular components of blood—can increase drug clearance, which may affect how you manage patients who donate plasma frequently.

Donated plasma is used to help patients with hemophilia and other blood disorders and burn victims. It’s also valuable for medical research. Typically, donors cannot be taking lithium, experiencing active hallucinations, receiving ≥3 psychotropic medications, or have had a psychiatric hospitalization in the past 12 months. Patients can donate while taking antidepressants, mood stabilizers, antipsychotics, and anticonvulsants.1

Pharmacotherapeutic concerns

During PP, solutes in plasma such as drugs can be removed, increasing drug clearance by 30%.2,3 PP affects both protein-bound and free drug concentrations. PP effectively clears drugs that are highly protein bound and have a small volume of distribution. As a result, serum levels of psychotropics are lowered. Most psychotropics except lithium are bound to plasma protein. Because of high protein binding, plasma concentrations of psychotropics may rebound after PP. Antipsychotics are highly protein bound—85% to 90%—and highly lipophilic. For a list of protein binding percentages of commonly used psychotropics, see the Table.4

Table

Protein binding percentages of common psychotropics

Drug(s)

Percentage of protein binding

Lamotrigine; topiramate

Minimal

Desvenlafaxine

30%

Carbamazepine

40% to 90%

Venlafaxine

40% to 50%

Oxcarbazepine

40% to 60%

Escitalopram

56%

All other SSRIs

75%

Bupropion

84%

Mirtazapine

85%

Duloxetine; divalproex

90%

Tricyclic antidepressants

98%

SSRIs: selective serotonin reuptake inhibitors
Source: Reference 4

Plasma is regenerated 24 to 48 hours after PP; therefore, the clinical effect on daily psychotropic dosing should be small unless the donations are frequent. Long-term and regular plasma donation may result in hypoalbuminemia and hypocholesterolemia5; however, the effects of hypoalbuminemia on psychotropics routinely bound to serum proteins are unknown. Patients with an acute infection or malnourishment could have further decreased albumin production or increased catabolism, resulting in a significant decrease in serum albumin concentration, which may affect psychotropic pharmacokinetics.5

Other concerns

Beware of financial incentives because economically disadvantaged psychiatric patients are vulnerable to coercion. Some plasma donor centers will pay donors a specific amount—ranging from $20 to $30— for their first 2 donations and offer monthly bonuses if a patient donates 8 times a month.

The amount of plasma a patient can donate is based on their weight; patients who weigh more get paid more. This may conflict with your attempts to motivate patients to lose weight.

Disclosures

Dr. Selvaraj receives an internal grant from Creighton University.

Drs. Gabel and Ramaswamy report no financial relationship with any company whose products are mentioned in this article or with manufacturers of competing products.

Acknowledgement

The authors would like to thank Darrel E. Willoughby, Librarian, Omaha Veterans Affairs Medical Center, Omaha, NE, for his assistance with this article.

References

1. American Red Cross. Eligibility criteria by topic. http://www.redcrossblood.org/donating-blood/eligibility-requirements/eligibility-criteria-topic#meds_vaccinations. Accessed April 11 2012.

2. Kale-Pradhan PB, Woo MH. A review of the effects of plasmapheresis on drug clearance. Pharmacotherapy. 1997;17(4):684-695.

3. Ibrahim RB, Liu C, Cronin SM, et al. Drug removal by plasmapheresis: an evidence-based review. Pharmacotherapy. 2007;27(11):1529-1549.

4. Clinical pharmacology online. http://www.clinicalpharmacology.com. Accessed April 11 2012.

5. Jones DK, Dunn MI. ‘Vampire syndrome’: serum protein and lipid abnormalities related to frequent sale of plasma. J Fam Pract. 1995;40(3):288-290.

Did you miss this content?
What stalking victims need to restore their mental and somatic health