Fatal overdose with amantadine

Covalent cucurbit[7]uril-dye conjugates for sensing in aqueous saline media and biofluids

Non-covalent chemosensing ensembles of cucurbit[n]urils (CBn) have been widely used in proof-of-concept sensing applications, but they are prone to disintegrate in saline media, e.g. biological fluids. We show here that covalent cucurbit[7]uril-indicator dye conjugates are buffer- (10× PBS buffer) and saline-stable (up to 1.4 M NaCl) and allow for selective sensing of Parkinson's drug amantadine in human urine and saliva, where the analogous non-covalent CB7⊃dye complex is dysfunctional. The in-depth analysis of the covalent host-dye conjugates in the gas-phase, and deionized versus saline aqueous media revealed interesting structural, thermodynamic and kinetic effects that are of general interest for the design of CBn-based supramolecular chemosensors and systems. This work also introduces a novel high-affinity indicator dye for CB7 through which fundamental limitations of indicator displacement assays (IDA) were exposed, namely an impractical slow equilibration time. Unlike non-covalent CBn⊃dye reporter pairs, the conjugate chemosensors can also operate through a SN2-type guest-dye exchange mechanism, which shortens assay times and opens new avenues for tailoring analyte-selectivity.

Case Reports Describing Amantadine Intoxication in a Rehabilitation Hospital

BACKGROUND

Amantadine is widely used to improve reduced spontaneity and prevent aspiration pneumonia. There are few reports on cases of amantadine intoxication in the field of rehabilitation.

CASES

Case 1 involved an 83-year-old man with a history of a lacunar infarction who was transferred to our rehabilitation hospital after a left femoral neck fracture and a left upper arm fracture. He had mild renal dysfunction. Although he was started on oral amantadine 150 mg/dayto reverse a decline in spontaneity, he could not begin rehabilitation therapy because of hallucinations and myoclonus. Furthermore, he developed aspiration pneumonia as a result of a consciousness disorder. After stopping amantadine, his toxic symptoms disappeared completely. Case 2 involved a 53-year-old man who was transferred to our hospital for rehabilitation after a brain contusion. He was started on oral amantadine 100 mg/day to reverse a decline in spontaneity. After amantadine was increased to 150 mg/day, myoclonus and hallucinations developed. At that time, his renal function was mildly impaired. The concentration of amantadine in his blood serum was found to be 4783 ng/dl. After amantadine was stopped, his spontaneity decline recurred. After restarting amantadine at 50 mg/day, his toxic symptoms did not reappear, and the decline in his spontaneity improved.

DISCUSSION

Amantadine is a renally excreted drug that may cause toxic symptoms as a result of decreased renal function. It is necessary to monitor renal function and toxic symptoms when amantadine is administered in rehabilitation hospitals.

A Novel Potent and Highly Specific Inhibitor against Influenza Viral N1-N9 Neuraminidases: Insight into Neuraminidase-Inhibitor Interactions

People throughout the world continue to be at risk for death from influenza A virus, which is always creating a new variant. Here we present a new effective and specific anti-influenza viral neuraminidase (viNA) inhibitor, 9-cyclopropylcarbonylamino-4-guanidino-Neu5Ac2en (cPro-GUN). Like zanamivir, it is highly effective against N1-N9 avian and N1-N2 human viNAs, including H274Y oseltamivir-resistant N1 viNA, due to its C-6 portion still being anchored in the active site, different from the disruption of oseltamivir's C-6 anchoring by H274Y mutation. Unlike zanamivir, no sialidase inhibitory activity has been observed for cPro-GUN against huNeu1-huNeu4 enzymes. Broad efficacy of cPro-GUN against avian and human influenza viruses in cell cultures comparable to its sialidase inhibitory activities makes cPro-GUN ideal for further development for safe therapeutic or prophylactic use against both seasonal and pandemic influenza.

Acute respiratory distress syndrome: A rare presentation of amantadine toxicity

PATIENT

Male, 64 FINAL DIAGNOSIS: Acute Respiratory Distress Syndrome (ARDS) Symptoms: Generalized myoclonic jerks • impaired concentration • memory decline • visual hallucinations

MEDICATION

Amantadine HCl Clinical Procedure: - Specialty: Toxicology.

OBJECTIVE

Adverse events of drug therapy.

BACKGROUND

Amantadine is indicated for treatment of influenza A infection, Parkinson disease and extrapyramidal reactions. Amantadine overdose affects mainly cardiovascular and central nervous systems. Amantadine-induced respiratory failure has not been described in previous case reports but it is a potential known side effect.

CASE REPORT

We describe the case of a 64-year-old African American male with end stage renal disease who was prescribed amantadine at a dose for normal kidney function (300 milligrams per day) for no clear reasons. PATIENT's serum level of amantadine drawn on admission was found to be 6200 nanogram per deciliter (ng/dl) with normal range being 700-1000 ng/dl. Amantadine hydrochloride is not actively metabolized in humans; is mainly excreted unchanged in urine by glomerular filtration and tubular secretion (90% of the ingested dose). It tends to accumulate in patients with impaired renal function; poorly excreted in patients on hemodialysis and has a large volume of distribution.

CONCLUSIONS

Our patient with impaired renal function was prescribed a much higher dose and eventually presented with high serum concentration of amantadine and neurological manifestations suggestive of amantadine toxicity. He developed sudden onset respiratory failure and pulmonary edema which is described as a potential lethal complication of amantadine toxicity. Since there is no specific etiology for his respiratory failure, this could represent the first reported case of Amantadine-induced Adult Respiratory Distress Syndrome (ARDS).

Cucurbit[7]uril as a "protective agent": controlling photochemistry and detecting 1-adamantanamine

Cucurbit[7]uril (CB[7]) as a "protective agent" can effectively inhibit the [4+4] photochemical reaction of 1,1'-(butane-1,4-diyl)bis(2-aminopyridine)bromide (DPAD) by host-guest interaction between CB[7] and DPAD. In addition, the host-guest complex DPAD-CB[7] as a supramolecular sensor can detect the concentration of 1-adamantanamine with good sensitivity and selectivity because of the guest competitive complexation.

Cardiotoxicity after massive amantadine overdose

INTRODUCTION

Amantadine hydrochloride is an antiviral medication used as therapy for parkinsonism and as a cognitive enhancer. We report 2 cases of massive, acute ingestion of amantadine hydrochloride confirmed with serial serum levels.

CASE REPORTS

A 47-year-old woman presented to the emergency department (ED) 30 minutes after ingesting 10 g of amantadine (150 mg/kg) by her report. Initial ECG revealed a sinus rhythm with rate of 93 bpm, and a QRS of 84 msec. While in the ED, the patient sustained a pulseless cardiac arrest and the monitor revealed ventricular tachycardia. She was successfully defibrillated. Postdefibrillation ECG showed a sinus rhythm (rate = 82 bpm), QRS of 236 msec, and QTc of 567 msec. The serum potassium was 1.0 mEq/L (1.0 mmol/L). The patient was given 300 ml (300 cc) 3% sodium chloride IV over 10 minutes. Ten minutes after completion of the hypertonic saline infusion, the patient's ECG abnormalities resolved and the QRS was 88 msec. Her potassium was repleted over the next 11 hours postpresentation, and she also received an IV bolus of 4 g of magnesium sulfate immediately after the cardiac arrest. No further hypotension, dysrhythmia, conduction delay, or ectopy was noted during the patient's hospital stay. The second case involved a 33-year-old female patient who presented 1 hour after ingesting 100 tablets of amantadine hydrochloride (100 mg/tab). Initial ECG revealed sinus tachycardia with a QRS of 113 msec, an R wave in lead aVR of 4-5 mm and a QTc of 526 msec. Her serum potassium was 3.0 mEq/L (3.0 mmol/L), her serum calcium was 9.4 mg/dl (2.35 mmol/L), and serum magnesium was 2.1 mg/dl (0.86 mmol/L) on labs drawn at initial presentation. The patient was intubated for airway protection, and her potassium was repleted and corrected over the next 9 hours. Her ECG abnormalities improved 8 hours after initial presentation and normalized at approximately 14 hours postingestion. The patient was discharged home 11 days after her ingestion.

CONCLUSION

Acute amantadine toxicity manifests with life-threatening cardiotoxicity. Concurrent, often profound, hypokalemia may complicate the administration of sodium bicarbonate in the management of cardiac dysrhythmias.

Fatal blood and tissue concentrations of more than 200 drugs

Fatal drug concentrations in body fluids and tissue samples are presented for more than 200 drugs and chemicals of toxicologic interest. Additionally, a reference list is added with more than 600 original papers concerning intoxications with a lethal outcome. The data can be helpful for the interpretation and plausibility control in own cases of intoxication. However, they should be used with caution, because use of drug data without sufficient knowledge about the patient or victim, the circumstances of the case, and about toxicokinetics and toxicodynamics might give a wrong interpretation in a special case.

Options for pharmacological management of obesity in patients treated with atypical antipsychotics

Obesity is associated with considerable morbidity and decreased life expectancy. Weight gain is a commonly encountered problem associated with antipsychotic treatment. We reviewed the literature regarding the mechanisms of weight gain in response to these agents and eight substances implicated as potential obesity prevention or treatment: orlistat, sibutramine, fluoxetine, topiramate, amantadine, nizatidine and cimetidine, and metformin. Weight gain in response to antipsychotic treatment may be mediated through serotonergic, dopaminergic, adrenergic, cholinergic, histaminergic and glutaminergic receptors. Sex hormone dysregulation and altered insulin sensitivity have also been implicated. Two compounds, orlistat and sibutramine, have been shown to help prevent weight gain following a hypocaloric diet, but orlistat requires compliance with a fat-reduced diet, and sibutramine is unsuitable for patients taking serotonergic agents. The weight reducing effect of fluoxetine, even in conjunction with a hypocaloric diet, is only transient. Topiramate, amantadine and metformin may have adverse side-effects potentially outweighing the weight reducing potential. The effectiveness of cimetidine and nizatedine remains unclear. The hazards of these agents in a psychiatric population are discussed. It is concluded that the current evidence does not support the general use of pharmacological interventions for overweight patients treated with antipsychotic medication, although individually selected patients may benefit.

What can we do about acute extrapyramidal symptoms?

Antipsychotic drugs are the most effective treatment for psychotic disorders such as schizophrenia. However, they are known to cause a range of side-effects including acute extrapyramidal symptoms (EPS) that are both distressing and disabling. Mental health nurses play a critical role in both the detection and the management of these symptoms. A review of the literature was conducted to identify strategies for managing acute EPS. Despite a widely held belief that EPS are associated with noncompliance with medication, the data to support this hypothesis are weak. Although akathisia may negatively affect the treatment outcome, there was little evidence to suggest that parkinsonism or dystonia do. Whilst the use of anticholinergic medication may be helpful in treating acute parkinsonism and dystonia they were associated with their own side-effects and the benefit of long-term prophylactic treatment is doubtful. The literature suggests that logical prescribing and rapid detection and management of acute EPS will result in a substantial reduction in the incidence of these disabling side-effects.

Amantadine-induced coma

Amantadine has found use primarily as an antiviral agent and in the symptomatic treatment of parkinsonism. However, the use of amantadine for the subjective alleviation of fatigue in multiple sclerosis and in the treatment of agitated aggressive behavior in the traumatic brain injured patient has also been described. Side effects of amantadine are primarily related to the central nervous system and include hallucinations, confusion, and nightmares. Toxic manifestations include acute psychosis, coma, cardiovascular toxicity, and death. Amantadine toxicity is a particular problem in patients with renal insufficiency because 90% of an oral dose is excreted unchanged in the urine. We present a case of amantadine-induced coma in a patient with multiple sclerosis and end-stage renal disease. Moreover, this degree of amantadine toxicity was profoundly apparent at a drug level usually not associated with such a severe presentation.

Acute psychosis after amantadine overdose

Amantadine is an antiviral agent that is also used in the treatment of parkinsonism and neuroleptic-induced extrapyramidal symptoms. Toxic effects of amantadine relate primarily to the central nervous system and range from mild symptoms to disorientation and hallucinations. Anti-cholinergic agents may exacerbate these effects. We report a case of unsuspected amantadine overdose in a previously healthy 35-year-old woman who presented with acute psychosis manifested by delirium and visual hallucinations. Concomitant use of diphenhydramine contributed to the clinical presentation. Amantadine toxicity should be considered in the differential diagnosis of altered mental status in patients known to be taking the drug or with conditions commonly treated with amantadine.