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Query: UMLS:C0040822 (tremor)
 18,428 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Barbiturates retain an important place in clinical neurological practice. They are used as both diagnostic and therapeutic drugs, their most common uses being as anticonvulsant and anaesthetic agents. This article explores the current theories explaining the mechanism of action of the barbiturates, with special emphasis on their anaesthetic and anticonvulsant effects. The primary mechanism of action of barbiturates is to increase inhibition through the gamma-aminobutyric acid (GABA) system. Anaesthetic barbiturates also decrease excitation via a decrease in calcium conductance. Phenobarbital (phenobarbitone), the primary anticonvulsant barbiturate, is effective for partial, complex partial and secondarily generalised seizures. While no longer the drug of choice for all these seizure types, it remains an important and useful agent. Mysoline has been shown to be useful in the treatment of essential tremor and several other movement disorders, and as an anticonvulsant. Barbiturates are also used for their sedative-hypnotic properties. A relatively new use is in the evaluation of patients with medically intractable seizure disorders for possible surgical therapy. The roles of methohexital and amobarbital (amylobarbitone) are discussed in the section on barbiturates used as diagnostic agents. The experimental use of barbiturates is also commented on; the most important of these is perhaps the use of barbiturates in cerebral resuscitation.
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PMID:The clinical use of barbiturates in neurological disorders. 172 Mar 79

Primidone was compared to the unselective beta adrenoceptor antagonist propranolol in the suppression of essential tremor. In a 4-week single-blind placebo-controlled study primidone was given in increasing doses from 62.5 mg X 1 up to 250 mg X 3 daily and propranolol 20 mg X 3 daily. The drugs produced a similar reduction in the degree of tremor after 2 and 1 weeks' medication respectively. This indicates that primidone can be an alternative to propranolol when beta-blockers are contraindicated. However, primidone was significantly even more effective in the beginning after only 2 doses, when at the same time 10 of 13 patients showed a maximum of acute toxic side-effects producing nausea, vomiting, giddiness and/or sedation. Correlation analysis between the individual tremor amplitude reductions and plasma primidone concentrations showed on the second day a tendency towards a greater reduction in tremor in those patients with the highest primidone plasma concentration. By the fourteenth day tremor had increased compared with the second day and correlation analysis between individual increase in tremor amplitude and plasma phenobarbital concentrations showed the highest degree of tremor increase in those patients who had the highest levels of phenobarbital. These and other data suggest that after the first doses, tremor suppression and acute toxicity is related to the initial exposure to primidone and the plasma level of the drug itself rather than its metabolites phenobarbital and phenylethylmalanomide. The individual tremor frequency spectrums did not change significantly during the placebo and propranolol periods, whereas the frequency tended to decrease during the primidone period.
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PMID:Primidone and propranolol in essential tremor: a study based on quantitative tremor recording and plasma anticonvulsant levels. 288 81

Orthostatic tremor is characterized by its isolated occurrence in leg and trunk muscles during standing with undisturbed sitting, lying and walking. In a female patient with this tremor syndrome the basic electrophysiological feature of muscle activity was a 16 Hz, highly synchronized tremor in all leg muscles and sometimes in the arm muscles. This rhythmic EMG activity however, was not restricted to stance but occurred during all kinds of muscle activation in sitting, lying or standing positions, despite only standing was accompanied by a subjective sensation of unsteadiness and falling to the ground. Mechanical tremor analysis at the patella revealed an additional 8 Hz tremor caused by alternating large and small amplitudes of the 16 Hz tremor bursts. The occurrence of the 8 Hz tremor was much more related to the feeling of unsteadiness than the 16 Hz tremor. Single motor units mostly fired at a frequency of 8 Hz, but only at the time of tremor bursts. Hence the 16 Hz-pattern may not be explained as the result of a pure motoneuronal abnormality. There were no indications for abnormal reflexes contributing to tremor genesis. A fixed time relation of the tremor bursts in different muscles has been found suggesting a common generator within the CNS for the tremor. After successfully treatment with Primidon the pattern of muscle activation was normalized during sitting and lying, however, during standing and walking the 16 Hz tremor was still present. We believe that an unknown central oscillator is causing the tremor and central structures which are involved in stance regulation have a predominant access to switch on this oscillator.
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PMID:[Orthostatic tremor: clinical aspects, pathophysiology and therapy]. 310

Uncontrolled clinical studies have suggested that primidone may be effective in reducing essential tremor thus providing a valuable alternative to beta-adrenoreceptor antagonists which are currently the drugs of first choice. A double blind, placebo controlled trial of primidone in essential tremor of the hands and head was carried out using both clinical and objective methods of assessment. Primidone was significantly superior to placebo in reducing the magnitude of hand tremor, its efficacy being comparable to that of propranolol. In two patients tremor was reduced to non-symptomatic levels, an effect rarely seen with propranolol. No consistent attenuation of head tremor was found. There was no correlation between serum primidone or derived phenobarbitone concentrations and the reduction of hand tremor. An acute toxic reaction to an initial small dose (62.5 mg) of primidone was seen in six of 22 patients.
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PMID:Primidone in essential tremor of the hands and head: a double blind controlled clinical study. 390 Feb 96

Primidone, 50 to 1,000 mg/d, reduced the amplitude of essential tremor in both untreated and propranolol-treated patients. Low doses were as effective as high doses. Primidone decreased tremor more than propranolol. There was no correlation between therapeutic response and serum levels. Acute reactions to the initial dose and side effects of higher doses caused drug intolerance. A single oral dose (250 mg) decreased tremor by 60% 1 to 7 hours after ingestion, with stable serum primidone levels but no detectable phenobarbital levels. Tremor control was lost when phenobarbital was substituted for primidone. Primidone is an effective agent for the treatment of essential tremor.
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PMID:Efficacy of primidone in essential tremor. 394 67

Primidone has been reported to be effective in reducing tremor in patients with benign essential tremor. There is at least one report that suggests that the medication may reduce voice tremor, a frequent component of the essential tremor syndrome. Three patients with spastic dysphonia of essential (voice) tremor and one with more typical essential (voice) tremor were treated with primidone and experienced no alleviation in the voice signs. The side effects experienced by all patients were consistent with those noted in previous reports. Primidone does not seem to be effective in treating essential voice tremor or spastic dysphonia of essential voice tremor.
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PMID:Spastic dysphonia and essential (voice) tremor treated with primidone. 672 82

Primidone given to a patient for epilepsy produced an unexpected reduction in benign familial tremor. Over the next eight years the drug was therefore tried in a prospective study of 20 other patients with benign familial tremor alone. Of these, six could not tolerate the drug because of vertigo and nausea but 12 obtained a good response, which in some cases was dramatic. Investigations in two patients suggested that the effect was mediated predominantly by derived phenylethylmalonamide, though primidone had some effect, since tremor recurred slightly on withdrawing the drug despite a constant or rising blood phenylethylmalonamide concentration. Primidone is highly effective in benign familial tremor. More patients with the condition are intolerant of the drug than are usually found with epilepsy.
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PMID:Benign familial tremor treated with primidone. 677 38

Essential tremor (ET) is the most prevalent tremor syndrome. It commonly affects the hands, head, voice, and other body parts. Appropriate management begins with correct diagnosis. Primidone and propranolol are the first-line medications for the treatment for ET, but several other medications may also provide benefit. In patients with medically refractory tremor, alternative therapies, including surgery or injections of botulinum toxin, may be considered.
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PMID:Management of essential tremor. 1204 52

Essential tremor is the most common of the movement disorders, being 20 times more common than Parkinson's Disease. It is characterised by postural and kinetic tremor which maximally affects the hands. It can be assessed by physiological techniques, subjective clinical methods, objective clinical methods and handicap/disability scales. Accelerometry, spirography and handwriting assessment, volumetry and handicap/disability questionnaires are commonly used methods. Primidone and propranolol are the first-line drugs. Several second-line drugs have been identified. Surgical techniques include lesioning or stimulation of the ventral lateral thalamus. Alcohol and botulinum toxin A are found to reduce tremor amplitude as well.
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PMID:Clinical features, assessment and treatment of essential tremor. 1283 51

Essential tremor is a common movement disorder that affects between 5 and 10 million persons in the United States. It is characterized primarily by an action and postural tremor most often affecting the arms, but it can also affect other body parts. Essential tremor is a progressive neurologic disorder and can cause substantial disability in some patients. Although there is no cure for essential tremor, pharmacologic and surgical treatments can provide some benefit. Primidone and propranolol are first-line treatments. Other medications with potential efficacy include benzodiazepines, gabapentin, topiramate, and botulinum toxin. Patients with medication-resistant tremor may benefit from thalamotomy or deep brain stimulation of the thalamus. The use of medical and surgical therapies can provide benefit in up to 80% of patients with essential tremor.
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PMID:Essential tremor: differential diagnosis and current therapy. 1289


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