Tremors associated with trimethoprim-sulfamethoxazole therapy in a patient with AIDS: case report and review

Acute movement disorders in the medical setting

Objective Psychosomatic medicine psychiatrists are often tasked with the evaluation and treatment of complex neuropsychiatric states which may be motoric in phenotype. Little energy has been dedicated to understanding acute movement disorders in the hospital environment. Method Recognizing the importance of frontal-subcortical (corticostriatothalamocortical) circuitry and basal ganglia structures, we present a case series of acute movement disorder phenotypes resulting from underlying medical conditions, commonly-administered medications, or the interaction of both. We organize these scenarios into neurodegenerative disorders, primary psychiatric disorders, neuroinflammation, and polypharmacy, demonstrating a clinical example of each followed by background references on a variety of clinical states and medications contributing to acute movement disorders. In addition, we offer visual illustration of implicated neurocircuitry as well as proposed neurotransmitter imbalances involving glutamate, gamma aminobutyric acid, and dopamine. Furthermore, we review the various clinical syndromes and medications involved in the development of acute movement disorders. Results Acute movement disorder's involve complex interactions between frontal-subcortical circuits and acute events. Given the complexity of interactions, psychopharmacological considerations become critical, as some treatments may alleviate acute movement disorders while others will exacerbate them. Conclusion Integrating underlying medical conditions and acutely administered (or discontinued) pharmacological agents offers an interactional, neuromedical approach to acute movement disorders that is critical to the work of psychosomatic medicine.

Tetrahydrobiopterin biosynthesis as an off-target of sulfa drugs

The introduction of sulfa drugs for the chemotherapy of bacterial infections in 1935 revolutionized medicine. Although their mechanism of action is understood, the molecular bases for most of their side effects remain obscure. Here, we report that sulfamethoxazole and other sulfa drugs interfere with tetrahydrobiopterin biosynthesis through inhibition of sepiapterin reductase. Crystal structures of sepiapterin reductase with bound sulfa drugs reveal how structurally diverse sulfa drugs achieve specific inhibition of the enzyme. The effect of sulfa drugs on tetrahydrobiopterin-dependent neurotransmitter biosynthesis in cell-based assays provides a rationale for some of their central nervous system-related side effects, particularly in high-dose sulfamethoxazole therapy of Pneumocystis pneumonia. Our findings reveal an unexpected aspect of the pharmacology of sulfa drugs and might translate into their improved medical use.

Memantine-Induced Myoclonus and Delirium Exacerbated by Trimethoprim

Objective:

To report a case of myoclonus and delirium seen in a patient taking a combination of memantine and trimethoprim.

Case Summary:

A 78-year-old woman was admitted to the medical center in October 2007 with rapid deterioration of Alzheimer's dementia and progressive myoclonus. In 2003, donepezil 5 mg/day had been initiated and her disease slowly progressed. In 2006, memantine 10 mg twice daily was added. Myoclonic activity and delirium were noted in 2007 when a urinary tract infection (UTI) was treated with double-strength trimethoprim/sulfamethoxazole (TMP/SMX 160 mg/800 mg). After discontinuation of TMP/SMX, the patient's condition returned to baseline level. Several weeks later, trimethoprim 100 mg daily was added for UTI prophylaxis. Within weeks, spontaneous generalized myoclonic activity resumed to the extent that the patient was unable to walk. She became increasingly delirious. A week before admission, levodopa/carbidopa 250 mg/100 mg was added for presumptive restless legs syndrome and the patient became extremely delirious and combative, requiring hospitalization. Because of the striking similarity of dose-related toxicities reported with amantadine, a slightly different aminoadamantane, memantine was withheld. Trimethoprim was discontinued due to a likely interaction with memantine. Donepezil and famotidine were withheld due to questions of therapeutic necessity. After 3 days, the myoclonus had completely resolved and the patient was no longer agitated or combative during the remainder of her hospitalization. She was cooperative and ambulatory and was discharged.

Discussion:

Memantine is cleared primarily through the kidneys and should be renally dosed. Drugs that interfere with elimination—that is, other drugs utilizing the organic cation transporter-2 in the tubule, such as trimethoprim, metformin, or imipramine—may lead to drug accumulation. Our patient, who had impaired renal function, developed severe myoclonus and delirium after trimethoprim was added to therapy with memantine. As there were no reports of myoclonus and delirium with this drug combination and because of the structural, pharmacologic, and pharmacokinetic similarities between the aminoadamantanes memantine and amantadine, we researched similar dual adverse effects reported with amantadine. Amantadine has led to the same adverse effects noted in our patient, not only in patients with renal impairment, but also in one patient when trimethoprim was added to a stable dose of amantadine.

Conclusions:

This is the first reported case of a drug interaction between memantine and trimethoprim, which resulted in clinically significant myoclonus and delirium. Clinicians should be aware of this potential interaction, since there have been reports of this adverse effect with the use of amantadine. Because memantine chemically and pharmacologically resembles amantadine, it is quite possible that their toxicities are similar.

Tremors and chorea induced by trimethoprim-sulfamethoxazole in a child with Pneumocystis pneumonia

A 1.5-year-old girl developed high frequency tremors and chorea after receiving a dose of 120 mg/kg/d trimethoprim-sulfamethoxazole (TMP-SMX) for the treatment of Pneumocystis pneumonia. The child was human immunodeficiency virus-negative but immunocompromised because of prolonged immunosuppressive therapy. These symptoms disappeared 3 days after TMP-SMX was discontinued. Pediatricians should be aware of tremors and chorea among the potential adverse effects of high doses of TMP-SMX.

Movement disorders and AIDS: a review

Movement disorders are a potential neurologic complication of acquired immune deficiency syndrome (AIDS), and may sometimes represent the initial manifestation of HIV infection. Dopaminergic dysfunction and the predilection of HIV infection to affect subcortical structures are thought to underlie the development of movement disorders such as parkinsonism in AIDS patients. In this review, we will discuss the clinical presentations, etiology and treatment of the various AIDS-related hypokinetic and hyperkinetic movement disorders, such as parkinsonism, chorea, myoclonus and dystonia. This review will also summarize current concepts regarding the pathophysiology of parkinsonism in HIV infection.

Adverse Reactions to Trimethoprim/Sulfamethoxazole in AIDS

OBJECTIVE

To report the case of a woman with AIDS who developed tremor, acute pancreatitis, and elevated serum creatinine levels while receiving trimethoprim/sulfamethoxazole (TMP/SMX).

CASE SUMMARY

A 37-year-old Puerto Rican woman with AIDS, HIV nephropathy, and a recent history of disseminated histoplasmosis presented with fever, nonproductive cough, pancytopenia, and elevated transaminase and alkaline phosphatase levels. Serum creatinine was near her baseline level of 2.9 mg/dL. Treatment was started with amphotericin B lipid complex for histoplasmosis and intravenous TMP/SMX for presumed Pneumocystis carinii pneumonia. Two days later, the patient developed a high-frequency tremor and severe abdominal pain, and serum creatinine increased to 5.6 mg/dL. TMP/SMX was discontinued, after which the patient's symptoms resolved within 72 hours and serum creatinine returned to baseline levels.

DISCUSSION

A high incidence of adverse reactions to TMP/SMX has been reported among HIV-infected persons. Toxic sulfamethoxazole metabolites may elicit hypersensitivity reactions. Trimethoprim can inhibit renal creatinine secretion, leading to high serum creatinine levels. Trimethoprim also inhibits dihydrofolate reductase, causing decreased dopamine production, which may lead to parkinsonian symptoms. Use of the Naranjo probability scale indicated a probable relationship between the adverse effect and TMP/SMX.

CONCLUSIONS

The high frequency and wide range of potential adverse effects associated with the use of TMP/SMX in HIV-infected persons require that clinicians consider drug toxicity as a cause of new symptoms in patients receiving this medication.

Acute delirium induced by intravenous trimethoprim-sulfamethoxazole therapy in a patient with the acquired immunodeficiency syndrome

The development of a rash in response to trimethoprim-sulfamethoxazole (TMP-SMX) administration is a frequent adverse reaction in people with the acquired immunodeficiency syndrome (AIDS). In contrast, there are no published reports in the English language literature describing TMP-SMX induced delirium in an AIDS patient. This report describes the development of frank delirium in a person with AIDS receiving TMP-SMX. The episode resolved completely within 72 h of withdrawal of the drug.

Trimethoprim-sulfamethoxazole-induced tremor in an immunocompetent patients

Trimethoprim-sulfamethoxazole (TMP-SMX) is a widely administered antibiotic that is well tolerated by most patients. Hypersensitivity reactions and gastrointestinal intolerance are the most common adverse events associated with it. Central nervous system adverse effects such as tremors are less common and occur primarily in patients with acquired immune deficiency syndrome. A 29-year-old immunocompetent man developed a tremor while taking TMP-SMX. The tremor resolved within 2 days after the drug was discontinued.

Trimethoprim/sulfamethoxazole-induced tremor in a patient with AIDS

OBJECTIVE

To report a case of trimethoprim/sulfamethoxazole (TMP/SMX)-induced tremor responsive to a reduction in dosage.

CASE SUMMARY

A 55-year-old white man with AIDS and Pneumocystis carinii pneumonia (PCP) developed a tremor after receiving 5 days of therapy with TMP/SMX 19.4 mg/kg/d (TMP). The tremor resolved completely 3 days after a dosage reduction to TMP/SMX 15.1 mg/kg/d.

DISCUSSION

Central nervous system adverse reactions to TMP/SMX have been reported in both the AIDS and non-AIDS populations. To our knowledge, this is the first reported case of TMP/SMX-induced tremor responsive to a reduction in dosage. Pharmacokinetic and clinical data suggest a concentration-dependent etiology for various adverse effects, including tremor. The mechanism of the tremor is unknown; however, toxic metabolites of SMX and disruptions of biogenic amine neurotransmission by TMP have been hypothesized.

CONCLUSIONS

TMP/SMX remains the drug of first choice for treating PCP, but it is clearly not well tolerated by patients with AIDS. Concentration-dependent toxicities such as tremor may lead to premature discontinuation of proven, effective TMP/SMX therapy. Using the lower end of the recommended dosing range for TMP/SMX (TMP 15 mg/kg/d) may reduce the incidence of these toxicities while still achieving acceptable TMP concentrations and antimicrobial efficacy.