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At least 19 recordsLinked to original sources
PubMed2000

Amantadine and rimantadine for preventing and treating influenza A in adults.

OBJECTIVES: Amantadine hydrochloride and rimantadine hydrochloride have antiviral properties, but they are not widely used due to a lack of knowledge of their properties and concerns about possible adverse effects. The objective of this review was to assess the effects and safety of amantadine and rimantadine in healthy adults. SEARCH STRATEGY: We searched the Cochrane Controlled Trials Register, Medline, Embase and reference lists of articles. We also contacted manufacturers, researchers and authors. SELECTION CRITERIA: Randomised and quasi-randomised studies comparing amantadine and/or rimantadine with placebo, control antivirals or no intervention, or comparing doses or schedules of amantadine and/or rimantadine in healthy adults. DATA COLLECTION AND ANALYSIS: For prevention trials the numbers of participants with clinically defined influenza, with serologically confirmed clinical influenza A and adverse effects were analysed. Analysis for treatment trials was of the mean duration of fever and adverse effects. MAIN RESULTS: Amantadine prevented 23% of clinical influenza cases (95% confidence interval 11% to 34%), and 63% of serologically confirmed clinical influenza A cases (95% confidence interval 42% to 76%) Amantadine reduced duration of fever by one day (95% confidence interval 0.7 to 1.3). Rimantadine demonstrated comparable effectiveness, but there were fewer trials and the results for prevention were not statistically significant. Both amantadine and rimantadine induced significant gastrointestinal adverse effects. Adverse effects of the central nervous system adverse and study withdrawals were significantly more common with amantadine than rimantadine. REVIEWER'S CONCLUSIONS: Amantadine and rimantadine have comparable effectiveness in the prevention and treatment of influenza A in healthy adults, although rimantadine induces fewer adverse effects than amantadine.

Adult↗
PubMed1999

In vivo analysis of amantadine renal clearance in the uninephrectomized rat: functional significance of in vitro bicarbonate-dependent amantadine renal tubule transport.

Amantadine transport into renal proximal and distal tubules is bicarbonate dependent. In the present study, we addressed the effects of bicarbonate on renal clearance and urinary excretion of amantadine. Renal clearance of kynurenic acid was also studied to determine whether bicarbonate effects are specific for organic base transport by the kidney. After a moderate diuresis was established, animals received i.v. [(3)H]amantadine or [(3)H]kynurenic acid followed by an acute dose of sodium bicarbonate or physiological saline. Urine and blood samples were analyzed for [(3)H]amantadine or [(3)H]kynurenic acid, blood gases, and pH. Amantadine and kynurenic acid were excreted by the kidneys, and both compounds underwent renal tubular secretion. Amantadine metabolism occurred, and one metabolite was detected in the urine. In the bicarbonate-treated rats, the total amount of amantadine excreted in the urine was decreased, whereas the amount of metabolite recovered was similar in both groups. Bicarbonate treatment caused a sustained increase in blood bicarbonate levels, a mild increase in blood pH, and a decrease in amantadine renal clearance and in the amantadine/creatinine clearance ratio. Only a transient decrease in the renal clearance of kynurenic acid and the kynurenic acid/creatinine clearance ratio was observed. This study demonstrates that short-term changes in bicarbonate concentration may have significant effects on renal organic cation elimination. Coupled with our previous in vitro demonstration of bicarbonate-dependent organic cation transport, the present study suggests that bicarbonate inhibition of renal tubule organic cation secretion may explain the previous observation that bicarbonate dosing decreases amantadine excretion by the kidney.

Amantadine↗
PubMed1997

Amantadine and equine influenza: pharmacology, pharmacokinetics and neurological effects in the horse.

Amantadine is an antiviral agent effective against influenza A viruses. We investigated 1) the antiviral efficacy, 2) analytical detection, 3) bioavailability and disposition, 4) pharmacokinetic modelling and 5) adverse reactions of amantadine in the horse. In vitro, amantadine and its derivative rimantadine suppressed the replication of recent isolates of equine-2 influenza virus with effective doses (EDs) of less than 30 ng/ml. Rimantadine was more effective than amantadine against most viral isolates; we suggest a minimum plasma concentration of 300 ng/ml of amantadine for therapeutic efficacy. In vivo an i.v. dose of amantadine 15 mg/kg bwt produced mild, transient CNS signs which were no longer apparent after 30 min. Amantadine administered at a dose of 15 mg/kg bwt was established as the maximum safe single i.v. dose. However, if repeated i.v. administration of amantadine is required no more than 10 mg/kg bwt t.i.d. should be used. The maximal safe plasma concentration of amantadine was not evaluated but is probably greater than 2000 ng/ml and possibly greater than 4000 ng/ml. On the other hand, horses with lower seizure thresholds, or those on medications that lower seizure thresholds, may be at increased risk of amantadine-induced seizures, which show few premonitory signs and are rapidly fatal. After i.v. administration of amantadine 10 mg/kg bwt, the disposition kinetics were well fitted by a 2-compartment open model. The estimated peak plasma concentration after this dose was about 4500 ng/ml, the volume of distribution at steady-state (Vdss) was (mean +/- s.d.) 4.9 +/- 1.9 l/kg bwt and the beta phase half-life was 1.83 +/- 0.87 h. Computer projections of plasma amantadine concentrations after i.v. administration of amantadine at a dose of 10 mg/kg bwt t.i.d. at 8 h intervals suggest peak plasma concentrations of 4000-5000 ng/ml and troughs of less than 300 ng/ml will be achieved. Amantadine administered orally at 10 mg/kg bwt and 20 mg/kg bwt showed mean oral bioavailability of about 40-60% and a plasma half life of 3.4 +/- 1.4 h; however, there was substantial inter-animal variation in bioavailability. Projections based on the kinetics observed in individual animals suggest that some animals readily maintain effective plasma concentrations of amantadine after oral administration of 20 mg/kg bwt t.i.d. On the other hand, animals in which amantadine is poorly bioavailable may require up to a 6-fold (120 mg/kg bwt) increase in the oral dose to achieve effective blood concentrations. Withholding food for 15 h did not reduce these inter-animal differences in bioavailability. Our results showed that simple dosing with oral amantadine will not yield effective plasma concentrations in all animals. While i.v. administration yielded more reproducible plasma concentrations, care should be taken to see that the seizure threshold is not exceeded. In acute situations, i.v. administration (5 mg/kg bwt) every 4 h should maintain safe and effective plasma and respiratory tract concentrations of amantadine.

Administration, Oral↗
PubMed2003

Amantadine in Parkinson's disease.

BACKGROUND: Although levodopa is the most common drug prescribed to relieve the symptoms of Parkinson's disease it is associated with motor and psychiatric side-effects. Consequently, interest has turned to alternative drugs with improved side-effect profiles to replace or augment levodopa. Amantadine, originally used as an antiviral drug, has been shown to improve the symptoms of Parkinson's disease. OBJECTIVES: To compare the efficacy and safety of amantadine therapy (monotherapy or adjuvant therapy) versus placebo in treating people with Parkinson's disease. SEARCH STRATEGY: Electronic searches of The Cochrane Controlled Trials Register (The Cochrane Library Issue 3, 2001), MEDLINE (1966-2001), EMBASE (1974-2001), SCISEARCH (1974-2001), BIOSIS (1993-2001), GEROLIT (1979-2001), OLDMEDLINE (1957-1965), LILACS (1982-2001), MedCarib (17th Century - 2001), PASCAL (1973-2001), JICST-EPLUS (1985-2001), RUSSMED (1973-2001), DISSERTATION ABSTRACTS (2000-2001), SIGLE (1980-2001), ISI-ISTP (1990-2001), Aslib Index to Theses (2001), Clinicaltrials.gov (2001), metaRegister of Controlled Trials (2001), NIDRR (2001) and NRR (2001) were conducted. Grey literature was hand searched and the reference lists of identified studies and reviews examined. The manufacturers of amantadine were contacted. SELECTION CRITERIA: Randomised controlled trials comparing amantadine with placebo in the treatment of patients with a clinical diagnosis of idiopathic Parkinson's disease. DATA COLLECTION AND ANALYSIS: Data was abstracted independently by NC and KD onto standardised forms and disagreements were resolved by discussion. MAIN RESULTS: Six randomised controlled trials were found comparing amantadine monotherapy or adjuvant therapy with placebo in the treatment of idiopathic Parkinson's disease. Five examined amantadine as adjuvant therapy with optimal levels of levodopa or anticholinergics and one examined amantadine as an adjuvant therapy with minimum tolerated levels of anticholinergics or as a monotherapy. Five were double-blind cross-over studies and one was a double-blind parallel group study. In total they examined 215 patients. The parallel group study allowed the randomisation codes to be broken and allowed patients in the placebo group to then receive amantadine. This could have led to bias. One study did not present the results of the placebo arm of the trial, hence we could not determine the difference between the two treatment groups. Two cross-over studies presented the results of the combined data from both treatment and placebo arms. The risk of carry-over effect into the second arm meant that these results could not be analysed. The final two studies presented at least some of their data from the end of the first arm of the trials. However only means were given, without standard deviations, so we could not determine the statistical significance of any difference between the amantadine and placebo groups. Although the authors did report on the side-effects from amantadine (such as livido recticularis, dry mouth and blurred vision), they state that none of them were severe. REVIEWER'S CONCLUSIONS: A considerable amount of evidence on the effectiveness of amantadine has accrued from non-controlled trials, often in patients with Parkinsonian conditions other than idiopathic Parkinson's disease. However, rigorous analysis of the six randomised controlled trials of amantadine reveals insufficient evidence of its efficacy and safety in the treatment of idiopathic Parkinson's disease.

Amantadine↗
PubMed1995

Therapeutic brain concentration of the NMDA receptor antagonist amantadine.

Amantadine (1-amino-adamantane) is clinically used for the management of Parkinson's disease and drug-induced extrapyramidal symptoms. It has previously been shown that amantadine is a low-affinity uncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist with rapid blocking and unblocking channel kinetics (Ki-value at the PCP binding site = 10 microM). The aim of the present studies was to estimate concentrations of amantadine in the central nervous system under therapeutic conditions. In homogenates of postmortem human brain tissue the amantadine concentration appeared to be homogeneously distributed over a wide range of brain areas. Amantadine concentration increased with duration of treatment and decreased wit drug-free time. When the duration of treatment was > or = 10 days and drug-free time < or = 3 days, mean amantadine concentrations in postmortem brain tissue ranged from 48.2 to 386 microM. In contrast to brain tissue, amantadine concentration in cerebrospinal fluid (CSF) and serum was in the low micromolar range ( < 17 microM). CSF and serum total values were highly correlated to each other and were always lower in CSF. The mean CSF/serum ratio for total amantadine was 0.76. To further estimate the extracellular concentration, amantadine was determined in microdialysates in the rat striatum. At behaviorally active doses, amantadine concentration in striatal microdialysates ranged between 6 and 21 microM. These results indicate that extracellular concentrations of amantadine (CSF and serum values in patients, striatal microdialysates in the rat) are in the range of its Ki-value at the PCP binding site. Amantadine concentrations in brain tissue are much higher, probably due to intralysosomal accumulation.

Aged↗
PubMed1991

Amantadine-related adverse reactions among African-American elderly nursing home residents.

To identify factors associated with the development of adverse reactions to amantadine prophylaxis for influenza in a predominantly African-American nursing home population, we retrospectively reviewed the records of 100 residents who did and 45 who did not receive amantadine. During the 4 weeks of amantadine treatment, three independent observers rated all new symptoms as either related or unrelated to amantadine. Two types of comparison were made. Among patients receiving amantadine, those who did or did not develop new symptoms believed to be related to amantadine were compared by age, underlying diagnoses, type and number of medications, and renal function. Similar comparisons were made between patients who did and those who did not receive amantadine. The 100 residents who received amantadine prophylaxis had significantly more nonspecific symptoms than the 45 who did not receive amantadine. Otherwise, the two groups were comparable with regard to age, renal function, number of diagnoses, and medications. Of the 100 residents given amantadine, 16% were judged to experience amantadine-related adverse reactions. Those developing amantadine-related symptoms were significantly more likely to have nonspecific symptoms and to use psychotropic medications.

Aged↗
PubMed2001

Amantadine inhibits RANTES production by influenzavirus-infected human bronchial epithelial cells.

1. Amantadine can prevent and decrease airway inflammation by inhibiting influenza virus (IV) replication; however, the effect of amantadine on RANTES production by human bronchial epithelial cells (BEC) has not been determined. In the present study, we examined the effect of amantadine on RANTES production and also analysed p38 mitogen-activated protein (MAP) kinase and c-Jun-NH2-terminal kinase (JNK) activation to clarify the mechanism in the effect of amantadine on RANTES production, since we have previously shown that p38 MAP kinase and JNK regulate RANTES production by IV-infected BEC. 2. BEC that had been preincubated with amantadine were infected with IV and then p38 MAP kinase and JNK activation in the cells and RANTES concentrations in the culture supernatants were determined. 3. Amantadine-induced inhibition of virus replication resulted in a decrease in p38 MAP kinase and JNK activity and decreased expression of RANTES in IV-infected cells. 4. Amantadine did not inhibit p38 MAP kinase and JNK activation induced by tumour necrosis factor-alpha (TNF-alpha) as a non-viral stimulus. 5. These results indicate that amantadine inhibits IV infection-induced RANTES production by human BEC and that the inhibition by amantadine of RANTES production might result from an indirect inhibitory effect of amantadine on p38 MAP kinase and JNK activation via the inhibition of virus replication, and we emphasize that amantadine may produce a beneficial effect on controlling bronchial asthma exacerbation caused by IV infection.

Amantadine↗
PubMed2004

Emergence and transmission of amantadine-resistant influenza A in a nursing home.

OBJECTIVES: To prospectively detect amantadine-resistant influenza when amantadine was used for influenza A outbreak control. DESIGN: Prospective clinical surveillance and viral culture of all new respiratory illnesses during the course of amantadine prophylaxis. SETTING: A 721-bed, 14-ward nursing home for veterans and spouses during an influenza A outbreak (1993-94). PARTICIPANTS: Residents of a veterans hospital and their spouses. MEASUREMENTS: Nasopharyngeal and throat viral culture. All residents with positive cultures who developed new respiratory symptoms while receiving or residing on a unit receiving amantadine prophylaxis had antiviral-resistance testing and polymerase chain reaction restriction analyses performed. RESULTS: Amantadine prophylaxis was administered sequentially on nine of 14 wards to all well residents for 14 to 31 days/ward to control influenza outbreaks between December 9, 1993, and January 28, 1994. Amantadine treatment was simultaneously provided to 29 ill residents. Between December 3, 1993, and January 22, 1994, 68 culture-positive cases of influenza A were detected. Twenty subjects were receiving or residing on units receiving amantadine prophylaxis. Amantadine sensitivity testing could be performed on 16 residents; 12 residents had amantadine resistant strains. Four of the 12 had not received any antiviral treatment. Illness onset ranged from 1 to 22 days after amantadine prophylaxis was begun on the individual's unit. Two ribonucleic acid (RNA) mutations in the gene coding the M2 protein transmembrane region were observed that were clustered in time and space. Isolates from two roommates, one receiving amantadine for 18 days and one on no antiviral, had identical RNA sequences. CONCLUSION: Antiviral resistance may be responsible for failure of prophylaxis in nursing home outbreaks. Strategies that use different classes of antivirals for prophylaxis and treatment may limit emergence and transmission of resistant virus.

Amantadine↗
PubMedDate not supplied

Mouse strain-dependent effect of amantadine on motility and brain biogenic amines.

The effect of amantadine hydrochloride, injected i.p. in 6 increments of 100 mg/kg each over 30 hr, on mouse motility and whole brain content of selected biogenic amines and major metabolites was studied in 4 strains of mice. These were the albino Sprague-Dawley ICR and BALB/C, the black C57BL/6 and the brown CDF-I mouse strains. Amantadine treatment produced a biphasic effect on mouse motility. The initial dose of amantadine depressed locomotor activity in all mouse strains studied with the BALB/C mice being the most sensitive. Subsequent amantadine treatments produced enhancement of motility from corresponding control in all mouse strains with the BALB/C mice being the least sensitive. The locomotor activity was decreased from corresponding controls in all strains studied, except for the ICR mice, during an overnight drug-free period following the fourth amantadine treatment. Readministration of amantadine, after a drug-free overnight period, increased motility from respective saline control in all strains with exception of the BALB/C mice where suppression of motility occurred. Treatment with amantadine did not alter whole brain dopamine levels but decreased the amounts of 3,4-dihydroxyphenylacetic acid in the BALB/C mice compared to saline control. Conversely, brain normetanephrine concentration was increased from saline control by amantadine in the BALB/C mice. The results suggest a strain-dependent effect of amantadine on motility and indicate a differential response to the acute and multiple dose regimens used. The BALB/C mouse was the most sensitive strain and could serve as the strain of choice for evaluating the side effects of amantadine. The biochemical results of brain biogenic amines of BALB/C mouse strain suggest a probable decrease of catecholamine turnover rate and/or metabolism by monoamine oxidase and a resulting increase in O-methylation of norepinephrine which may account for a behavioral depression caused by amantadine in the BALB/C mice.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1996

Use of digitalis glycosides to identify the mechanisms of amantadine transport by renal tubules.

The mechanism(s) for uptake of organic cations by renal cortical tubules was (were) examined further. Renal cortical tubules were purified from rat kidneys by a Percoll gradient centrifugation technique. Bicarbonate buffer (Krebs-Henseleit, KHS) conditions were altered, and chemical modulators were used which affect the activity of the basolateral Na+/K+-ATPase. Renal tubule uptake of the achiral organic cation amantadine was determined. The cardiac glycosides digoxin and acetylstrophanthidin and ouabagenin did not alter amantadine uptake by either proximal or distal tubule fragments in KHS. However, ouabain inhibited proximal tubule amantadine uptake in a dose-dependent manner with lower potency than distal tubule amantadine uptake in KHS. Ouabain did not inhibit amantadine tubule uptake in phosphate buffer. However, inhibition of amantadine uptake by ouabain returned in a time-dependent manner upon addition of bicarbonate to the phosphate buffer. Low extracellular sodium or potassium did not alter amantadine uptake by proximal tubules. Hypokalemic and hypokalemic/ hyponatremic conditions decreased the inhibitory potency of ouabain for amantadine uptake by proximal tubules. For distal tubules, both hyponatremic and hypokalemic conditions, alone and together, decreased the inhibitory potency of ouabain, but did not affect amantadine uptake in the absence of ouabain. Hypochloremic conditions decreased affinity for amantadine uptake by distal, but not proximal tubules. No change in maximal transport capacity for amantadine uptake was observed under hypochloremic conditions for either tubule fragment. These studies challenge the widely accepted concept of Na+/ K+-adenosine triphosphatase activity and maintenance of the basolateral membrane potential as rate-limiting steps for the energy-dependent renal tubule uptake of organic cations. Furthermore, these studies suggest a mechanism for ouabain inhibition of organic cation renal tubule uptake that may not involve the Na+/K+-adenosine triphosphatase and may be possibly bicarbonate-dependent.

Amantadine↗
PubMed2000

Comparison of central nervous system adverse effects of amantadine and rimantadine used as sequential prophylaxis of influenza A in elderly nursing home patients.

BACKGROUND: Amantadine hydrochloride and rimantadine hydrochloride are recommended by the Centers for Disease Control and Prevention for prophylaxis of influenza A. While data suggest that rimantadine is better tolerated, there are no data examining the rate of adverse reactions in elderly patients who receive amantadine vs rimantadine. Our objective was to assess the adverse reaction rate in elderly nursing home patients receiving sequential amantadine and rimantadine for influenza A prophylaxis. METHODS: Data were collected in 156 nursing home patients (70% women; mean+/-SD age, 83.7+/-10.1 years) in a single care setting who received sequential therapy with amantadine and rimantadine during the 1997-1998 influenza season. Patients were assessed for central nervous system adverse effects and therapy discontinuation occurring with each agent. RESULTS: Twenty-nine (18.6%) of the 156 patients experienced an adverse effect when receiving amantadine compared with 3 patients (1.9%) when rimantadine was given (P<.01). Drug use was discontinued due to adverse events in 17.3% (n = 27) of the amantadine courses and 1.9% (n=3) of the rimantadine courses (P<.001). Confusion was the most frequently observed adverse event (amantadine, 10.6%; rimantadine, 0.6%; P<.001). Multivariate logistic regression analysis showed that significant risk factors for central nervous system adverse events included male sex (odds ratio, 3.65), reduced calculated creatinine clearance (odds ratio, 1.78), and use of amantadine (odds ratio, 12.73). CONCLUSIONS: Amantadine use was associated with a significantly higher incidence of central nervous system adverse events than rimantadine use in this elderly population receiving influenza prophylaxis. In addition, the discontinuation rate of amantadine was significantly higher than that with rimantadine.

Adverse Drug Reaction Reporting Systems↗
PubMed2003

A randomized trial of amantadine in Huntington disease.

CONTEXT: Huntington chorea, like levodopa-induced dyskinesias, may be responsive to amantadine hydrochloride treatment. OBJECTIVES: To measure the effect of amantadine treatment on Huntington chorea and to test a hypothesis that the adventitious movements are associated with reduced central proprioception that can be corrected by amantadine treatment. DESIGN: A randomized placebo-controlled cross-over trial with 2 weeks of treatment. SETTING: A tertiary referral center. PARTICIPANTS: Twenty-four subjects with Huntington disease took amantadine hydrochloride, 100 mg 3 times daily for 2 weeks, and placebo for 2 weeks. METHODS: Chorea of the face, trunk, and limbs while seated was videotaped at baseline and after each study phase. Segments were viewed in random order by blinded reviewers and scored. Proprioception was determined using arm restraints in which the right and left elbows were set at slightly different angles, and the errors in selecting the more extended elbow over 40 trials were recorded. RESULTS: The chorea score was not correlated with a proprioception deficit. Neither chorea nor proprioception were significantly affected by amantadine therapy. The chorea score was 9.6 (3.1) points at baseline and 9.7 (3.7) points when the patient was receiving amantadine therapy. The 95% confidence interval for the difference between placebo effect and amantadine effect was -1.43 to 1.0 points. Despite this, 19 subjects felt improved during the amantadine phase compared with 6 subjects improved in the placebo phase (P =.006) and the quality of life was better (P<.001). CONCLUSIONS: Elbow proprioception was not shown to be related to Huntington chorea. Amantadine hydrochloride treatment at doses of 300 mg/d had no effect, on average, for Huntington chorea, although most patients felt subjectively better during the short course of amantadine treatment.

Amantadine↗