Effect of lithium carbonate on zidovudine-associated neutropenia in the acquired immunodeficiency syndrome

Drug-drug interactions and clinical considerations with co-administration of antiretrovirals and psychotropic drugs

Psychotropic medications are frequently co-prescribed with antiretroviral therapy (ART), owing to a high prevalence of psychiatric illness within the population living with HIV, as well as a 7-fold increased risk of HIV infection among patients with psychiatric illness. While ART has been notoriously associated with a multitude of pharmacokinetic drug interactions involving the cytochrome P450 enzyme system, the magnitude and clinical impact of these interactions with psychotropics may range from negligible effects on plasma concentrations to life-threatening torsades de pointes or respiratory depression. This comprehensive review summarizes the currently available information regarding drug-drug interactions between antiretrovirals and pharmacologic agents utilized in the treatment of psychiatric disorders-antidepressants, stimulants, antipsychotics, anxiolytics, mood stabilizers, and treatments for opioid use disorder and alcohol use disorder-and provides recommendations for their management. Additionally, overlapping toxicities between antiretrovirals and the psychotropic classes are highlighted. Knowledge of the interaction and adverse effect potential of specific antiretrovirals and psychotropics will allow clinicians to make informed prescribing decisions to better promote the health and wellness of this high-risk population.

Restarting clozapine after neutropenia: evaluating the possibilities and practicalities

Clozapine remains the antipsychotic of choice for refractory schizophrenia despite its propensity for serious blood disorders. When neutropenia or agranulocytosis occur in people taking clozapine, cessation of treatment is mandated and relapse often results. Because such patients are usually unresponsive to other antipsychotics, many clinicians consider restarting clozapine, despite the risks involved. However, the risks of clozapine rechallenge vary according to the cause and nature of the blood dyscrasia. Neutropenia can arise because of factors unrelated or indirectly related to clozapine treatment. These include benign ethnic neutropenia, concomitant drug therapy, co-existing medical conditions and drug interactions. In such cases, clozapine may be restarted if non-clozapine causes of neutropenia are identified and eliminated, although concurrent treatment with lithium (to induce leukocytosis) is sometimes necessary. Close monitoring of the patient is essential because it is rarely possible to completely rule out the contribution of clozapine to the blood dyscrasia and because lithium does not protect against clozapine-related agranulocytosis. In cases of clozapine-induced neutropenia (as distinct from agranulocytosis, which may have a different pathology) rechallenge may also be considered and, again, lithium co-therapy may be required. Where clozapine is clearly the cause of agranulocytosis, rechallenge should not be considered or undertaken unless there are very exceptional circumstances (severe and prolonged relapse following clozapine discontinuation). In these cases, re-exposure to clozapine may rarely be attempted where there are facilities for very close and frequent monitoring. Granulocyte colony-stimulating factor is likely to be required as co-therapy, given the very high likelihood of recurrence. Uncertainty over the likely cause of blood dyscrasia in people taking clozapine, coupled with uncertainty over the mechanism by which clozapine causes both neutropenia and agranulocytosis, makes any attempt to restart clozapine a high-risk venture requiring the utmost caution.

Hemodynamic, electrocardiographic, metabolic, and hematologic abnormalities resulting from lithium intoxication. A case report

The authors report a unique case that presented with hemodynamic abnormalities and severe bradycardia, necessitating the insertion of a temporary pacemaker, as well as metabolic disturbances, hematologic changes, and hepatic and renal dysfunction in an elderly individual owing to lithium intoxication. This case also demonstrates that these various serious side effects of lithium resolved with prompt recognition and discontinuation of lithium. Lithium should be used with extreme caution and frequent monitoring especially in the elderly.

Pharmacotherapy of HIV dementia

OBJECTIVE

To review the clinical presentation and management of cognitive impairment associated with central nervous system HIV type 1 (HIV-1) infection.

DATA SOURCES

A MEDLINE search pertaining to HIV-related dementia (HIV-D) and pharmacologic management was performed. Additional literature was obtained from reference lists of the identified articles.

STUDY SELECTION AND DATA EXTRACTION

All clinical trials and case reports evaluating pharmacologic efficacy in terms of clinical response, cerebrospinal fluid (CSF) changes, and neuropathology were considered for inclusion. Selection was not restricted by study design because most information consists of open uncontrolled trials and case reports.

DATA SYNTHESIS

HIV-D is characterized by a triad of disturbances in cognition, motor performance, and behavior in adults. Children present with developmental delay, cognitive impairment, poor brain growth, and other neurologic symptoms. The exact pathophysiologic mechanisms of HIV-D are not known. Numerous pharmacologic agents (e.g., nucleoside reverse transcriptase inhibitors, pentoxifylline, nitroglycerin, memantine, nimodipine, peptide T) are under investigation for management of HIV-D. Zidovudine is the most thoroughly investigated medication, with patients developing HIV-D less frequently and showing improvement on neuropsychological, CSF, and neuropathologic evaluations. Sustained response to zidovudine lasts 6 months to 1 year and optimal response is achieved at higher, but less tolerated, dosages. HIV-D patients frequently have comorbid psychiatric disorders requiring psychopharmacologic agents and are sensitive to the adverse effects of these medications.

CONCLUSIONS

HIV-D is a devastating complication of HIV-1 infection. Zidovudine is the therapy of choice for prevention and management of cognitive impairment in symptomatic HIV-infected patients and patients with AIDS. Recommendations for other medications cannot be made secondary to lack of data. The management of HIV-D may include multiple agents as more data become available regarding combination therapy. Well-designed controlled trials are needed to evaluate the efficacy of established treatments and investigational medications in the management of HIV-D.

Effect of lithium in immunodeficiency: improved blood cell formation in mice with decreased hematopoiesis as the result of LP-BM5 MuLV infection

Lithium salts have been demonstrated to induce the production of hematopoietic cells following administration in vivo and to minimize the reduction of these cells following treatment with either radiation, chemotherapeutic or antiviral drugs. We have previously demonstrated that lithium, when administered in vivo to immunodeficient mice infected with LP-BM5 MuLV (MAIDS) significantly reduced the development of lymphadenopathy, splenomegaly, and the lymphoma associated with late-stage immunodeficiency disease in this model, and increased the survival of these animals compared to virus-infected controls not receiving lithium. We report here the results of in vivo studies in the MAIDS model that determined the effect of lithium on peripheral blood indices and the number of myeloid (CFU-GM), erythroid (BFU-E) and megakaryocyte (CFU-Meg) hematopoietic progenitors from bone marrow and spleen harvested from immunodeficient mice receiving lithium carbonate (1 mM) placed in their drinking water compared to virus-infected controls not receiving lithium. Time-points evaluated were at weeks 1, 5, 9, 13, 17, and 21 postviral infection. Virus-control mice not receiving lithium demonstrated all the signs that are characteristic of MAIDS, i.e., splenomegaly, lymphadenopathy, hypergammaglobulinemia, reduced hematopoiesis, and death. Infected mice receiving lithium demonstrated diminished presence of splenomegaly, lymphadenopathy, hypergammaglobulinemia, no suppression of hematopoiesis nor mortality. Enhanced hematopoiesis was demonstrated by neutrophilia, lymphocytosis, thrombocytosis, and erythrocytosis that was evident by increased myeloid, erythroid, and megakaryocyte progenitor cells cultured from bone marrow and spleen. These studies further demonstrate that lithium influences the disease process in the MAIDS model and restricts the development of hematopoietic suppression that develops in this retroviral animal model of immunodeficiency.

Management of lithium in patients with cancer

This article reviews the management of lithium in patients who require optimum management of cancer and simultaneous prevention of mania or depression in lithium-sensitive affective illness. Two cases are described. Discussion focuses on whether lithium should be continued during chemotherapy and radiation treatment, the complications that would lead to lithium toxicity in an otherwise stable patient, the likely settings for hypothyroidism, and the role of lithium to stabilize steroid-induced affective changes. The authors conclude that lithium may be withheld 1 or 2 days before cytotoxic chemotherapy and restarted when the patient is able to drink. It may be given as usual through routine radiation treatment, but it should be discontinued during cranial radiation. Calcium, renal, cardiac, and thyroid functions should be monitored.

Pharmacokinetics and pharmacodynamics of granulocyte-macrophage colony-stimulating factor and zidovudine in patients with AIDS and severe AIDS-related complex

Granulocytopenia is a complication of human immunodeficiency virus disease, as well as a toxic manifestation of zidovudine therapy. To evaluate pharmacokinetic and pharmacodynamic relationships, 11 AIDS-AIDS-related complex patients who had developed zidovudine-associated granulocytopenia (mean absolute neutrophil count, 1,077/mm3) were examined after addition of granulocyte-macrophage colony-stimulating factor (GM-CSF) to zidovudine. GM-CSF was administered as a daily (1.0 or 0.3 micrograms/kg) or every-other-day (0.3 micrograms/kg) subcutaneous dose over a 28-day period. Zidovudine was continued at the same daily dosage as was previously being administered. Of 11 patients, 7 (1.0 micrograms/kg, n = 5; 0.3 micrograms/kg, n = 2) had a pharmacologic response to GM-CSF with an increase to a mean absolute neutrophil count of 3,189 cells per mm3 at 4 weeks (P < 0.05). The peak concentration of GM-CSF in plasma ranged from 11.5 to 84.4 pg/ml, and the time to peak ranged from 1 to 3 h. No correlation between GM-CSF disposition and hematologic response was noted. A decreased plasma zidovudine-glucuronide/zidovudine ratio was noted after 1 week of GM-CSF, and an increase in the area under the plasma concentration-versus-time curve for zidovudine was found in three patients after 4 weeks. Low doses of GM-CSF can raise the granulocyte count in patients with zidovudine-induced neutropenia. The use of GM-CSF and zidovudine may represent a viable treatment option for persons with human immunodeficiency virus infection who develop neutropenia while receiving zidovudine but do not tolerate alternative nucleoside analogs. Further studies are needed to assess the complex interaction between these two agents.

Modulation of the haematopoietic toxicity associated with zidovudine in vivo with lithium carbonate

The drug zidovudine (AZT), a synthetic thymidine analogue, has been used in the treatment of acquired immunodeficiency syndrome (AIDS). Clinical use of zidovudine has induced haematopoietic toxicity manifested by anaemia, neutropenia, and overall bone marrow suppression. The monovalent cation lithium has been shown to be an effective agent capable of modulating several aspects of haematopoiesis such as the induction of neutrophilia, thrombopoiesis, and protection against suppression of hematopoietic progenitor stem cells following exposure to anti-cancer drugs and/or radiation at doses commonly used in the treatment of malignant disease. We report here the result of studies designed to evaluate the effectiveness of lithium in reversing zidovudine-induced haematopoietic suppression when administered to normal mice in vivo in the presence of dose-escalation zidovudine. Lithium carbonate (Li2CO3) reversed zidovudine toxicity as measured by increases in peripheral WBC, platelets, and CFU-GM and CFU-Meg haematopoietic progenitors; however lithium was insufficient in reversing the reduction of erythropoiesis associated with zidovudine use in vivo. These results further confirm the effective use of lithium to reverse the development of myelosuppression and thrombocytopenia associated with the anti-viral drug zidovudine, but is less effective in ameliorating the induction of anaemia.

Effective modulation of the haematopoietic toxicity associated with zidovudine exposure to murine and human haematopoietic progenitor stem cells in vitro with lithium chloride

The drug zidovudine (AZT), a synthetic thymidine analogue, has been used in the treatment of acquired immunodeficiency syndrome (AIDS). Clinical use of zidovudine has induced haematopoietic toxicity manifested by anaemia, neutropenia, frequent thrombocytopenia, and overall bone-marrow suppression. The monovalent cation lithium has been shown to be an effective agent capable of modulating several aspects of haematopoiesis such as the induction of neutrophilia, thrombopoiesis, and protection against suppression of haematopoietic progenitor stem cells following exposure to anticancer drugs and/or radiation in the treatment of malignant disease. We here report the results of studies designed to evaluate the effectiveness of lithium in reversing and/or protecting against either murine or human bone marrow derived haematopoietic progenitors, i.e. (CFU-GM, CFU-Meg, and BFU-E) when co-cultured in the presence of zidovudine in vitro. Lithium chloride (LiCl) reversed zidovudine toxicity to either murine or human derived CFU-GM and CFU-Meg that was optimal at a concentration of 1 mM (P less than 0.05). However, the addition of lithium failed to influence zidovudine toxicity toward either murine or human BFU-E. In summary, these results support the scant clinical studies that have described the presence of neutrophilia and/or thrombopoiesis in zidovudine-treated AIDS patients receiving lithium. In addition, these data further confirm the need for more detailed evaluation of lithium as an adjuvant agent to reduce the haematopoietic toxicity associated with the use of antiviral therapy in HIV-infected patients.

ARDS following acute lithium carbonate intoxication

Lithium is a two-edged sword; it is on the one hand a unique drug with invaluable psychoactive potential and on the other a drug which can cause multisystem toxicity and even death. We present a case of severe lithium intoxication with multiple organ involvement. Our patient developed the adult respiratory distress syndrome (ARDS), nephrogenic diabetes insipidus (DI), distinctive neurological abnormalities, and hyperglycemia. We believe that this is a case of ARDS due to lithium toxicity in which elevated left atrial pressures were excluded by right heart catheterization and suggest a causal relationship between lithium and ARDS.

Kaposi sarcoma associated with human immunodeficiency virus infection

In the present study, 11 patients with epidemic Kaposi sarcoma were evaluated; 55% were in stage IV and 45% in stage II; in addition, 75% had systemic symptoms, 89% had low total and T-lymphocyte counts, and all of them had not only low T-helper lymphocyte counts but also T-helper/T-suppressor ratios. The majority of patients (89%) had low proliferative responses with phytohemagglutinin (PHA). Nine patients were treated with: alpha-2 interferon (five patients), zidovudine (two patients), doxorubicin and zidovudine (one patient), and radiotherapy (one patient). There were only five patients with stable disease, three treated with alpha-2 interferon, one with doxorubicin, and one with doxorubicin plus azidothymidine. Two patients (one with doxorubicin and one with doxorubicin plus zidovudine) needed lithium to increase leukocyte and platelet counts. In May 1989, 73% of patients were dead (median survival 8 +/- 2 months). It is concluded that: (1) it is important to select the patients who have the best chance to improve with treatment; (2) the response with alpha-2 interferon or monochemotherapy is low and there is no change in overall survival; (3) a low helper cell count, low T-helper/T-suppressor ratio, and low proliferative response with mitogens are features of poor prognosis; (4) toxicity with treatment was acceptable; and (5) lithium increased neutrophil and platelet counts.

Synergy of inhibition of DNA synthesis in human bone marrow by azidothymidine plus deficiency of folate and/or vitamin B12?

The effect of azidothymidine (Zidovudine, AZT) on pyrimidine (thymidine, deoxyuridine, and thymidine triphosphate) incorporation into DNA in folate- and/or vitamin B12-deficient and normal human bone marrow cells was studied to investigate whether such vitamin deficiency affects susceptibility to AZT-induced hematologic toxicity. Bone marrow cells from 12 patients were studied: 5 had folate and/or vitamin B12 deficiency; 7 controls included 5 with anemia related to chronic disease and 2 with iron deficiency. At 0.2 microM AZT (3 hr, 37 degrees C), the approximate pharmacologic serum trough level, pyrimidine incorporation into DNA was suppressed by 12 to 19% in folate- and/or vitamin B12-deficient cells and by 16 to 23% in normal cells. At 2.0 microM AZT (3 hr, 37 degrees C), the approximate pharmacologic serum peak level, this was suppressed by 15 to 40% in folate- and/or vitamin B12-deficient cells and by 32 to 47% in controls. Deoxyuridine incorporation into DNA was inhibited significantly greater than thymidine at 2.0 microM AZT (3 hr, 37 degrees C) in both groups. Inhibition of deoxyuridine incorporation was not reversed with methyltetrahydrofolate or vitamin B12. There tended to be less striking suppression by AZT of deoxyuridine incorporation into DNA in bone marrow cells from vitamin B12-deficient patients, which was made more striking by adding vitamin B12. This suggests that some of what passes for "AZT damage" to bone marrow cells may in fact be coincident deficiency of vitamin B12. AZT inhibition of DNA synthesis in 3 hr bone marrow cultures is relatively consistent in a variety of hematologic disorders. As approximately two-thirds of AIDS patients appear to be in negative balance with respect to folate and/or vitamin B12, the fact that AZT-induced inhibition of pyrimidine incorporation into DNA is occurring in cells which may be megaloblastic, i.e., in a state of impaired DNA synthesis, suggests that these cells may be more susceptible to AZT toxicity. The data also support the notion that AZT inhibition results predominantly from termination of DNA chain elongation. Whether folate or vitamin B12 supplementation may partially overcome apparent "AZT inhibition" of DNA synthesis (hematologic toxicity) and whether the benefit of such therapy exceeds the risk will require further study.

Zidovudine. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic efficacy

Zidovudine (azidothymidine) is a thymidine analogue antiretroviral drug active against human immunodeficiency virus (HIV). In acquired immunodeficiency syndrome (AIDS) and AIDS-related complex (ARC) patients, orally and intravenously administered zidovudine is effective in reducing the incidence of opportunistic infections and neoplasms, increasing helper T lymphocyte numbers, and improving survival rates and quality of life. Adverse effects include serious haematological abnormalities and severe headache, abdominal discomfort, nausea, myalgia and insomnia. In addition, neutropenia and other anaemias frequently limit zidovudine therapy and may result in a need for multiple blood transfusions, dose reductions or withdrawal of the drug. However, despite these problems and the lack of information about some aspects of zidovudine use, zidovudine provides a major hope for HIV-infected patients, and it has rapidly become the standard therapy for improving the quality and duration of the lives of AIDS and ARC patients.