Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0012833 (dizziness)
 9,689 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Many substances may be the source of dizziness or transient equilibrium disturbances due to dysfunction of the CNS or to an impairment of visual or proprioceptive informations. Other agents are responsible for drop of arterial pressure by changing position, including antihypertensive drugs, alpha-blocking agents used in urology, antipsychotics, cyclic antidepressants, vasodilators and nitrates, dopaminergic antiparkinson drugs, sedatives, etc. Only drug with true ototoxic properties will be discussed here, namely substances that are able to damage the inner ear (cochlear or vestibular damage) or the VIIIth cranial nerve, causing impairment of equilibrium and/or (most often) hearing. No relevant data report the actual incidence of ototoxic problems, but more than 130 products have been classified as potentially dangerous. Individual susceptibiity seems highly variable, but some predisposing factors have been identified: renal failure, age, combination of ototoxic drugs, familial sensitivity to ototoxic effects or previous neurosensorial deficit. We will first discuss the ototoxic medications that have certainly been extensively studied and among which we find several antibiotics (especially aminoglycosides and macrolides), the loop diuretics, and some antimalarial or chemotherapeutic agents. Environmental toxins and drug of abuse will then be discussed briefly because scientific data are much less significant. Early recognition of subjects who are at risk of developing ototoxicity, use of therapeutic monitoring and close observation of cochleo-vestibular functions in high risk situations (often not easy in critical patients) are the best way to prevent severe complications that have occasionally disastrous consequences on the quality of further life.
 ...
PMID:[Ototoxicity-related dysequilibrium]. 1555 24

Candesartan cilexetil is the prodrug of candesartan, an angiotensin II receptor antagonist. Candesartan binds selectively and non-competitively to the angiotensin II receptor type 1, thus preventing the actions of angiotensin II. Clinical trials have demonstrated its efficacy at a dose range of 2 to 32 mg once daily in hypertension of all grades, heart failure, in reducing urinary albumin excretion in diabetes mellitus and in coexisting hypertension and renal failure. Pharmacokinetic properties of candesartan cilexetil in elderly patients are not significantly different from those in younger individuals. Hepatic impairment does not change pharmacokinetics of candesartan cilexetil at doses up to 12 mg/day. No dose adjustment is necessary in patients with mild or moderate renal impairment. Tolerability of candesartan cilexetil is not much different from that of placebo. All adverse events are usually of mild to moderate severity and not dose-related. The most common adverse events were headache, upper respiratory tract infection, back pain, and dizziness. The incidence of these adverse effects, as well as of cough, was similar in patients treated with candesartan cilexetil or placebo. The incidence of adverse events in long-term trials was not different from that in short-term trials. Tolerability of candesartan cilexetil does not differ with either age or gender.
 ...
PMID:Candesartan. 1559 74

On May 19, 2004, azacitidine (5-azacytidine; Vidaza(trade mark); Pharmion Corporation, Boulder, CO, http://www.pharmion.com) for injectable suspension received regular approval by the U.S. Food and Drug Administration (FDA) for the treatment of all subtypes of myelodysplastic syndrome (MDS). This report summarizes the basis for this approval. Effectiveness was demonstrated in one randomized, controlled trial comparing azacitidine administered s.c. with best supportive care (observation group) and in two single-arm studies, one in which azacitidine was administered s.c. and in the other in which it was administered i.v. The dose of azacitidine, 75 mg/m2/day for 7 days every 28 days, was the same in all three studies. In the randomized trial, study participants were well matched with respect to age, sex, race, performance status, MDS subtype, and use of transfusion during the 3 months before study entry. Patients in the observation arm were permitted by protocol to cross over to azacitidine treatment if their disease progressed according to prespecified criteria. During the course of the study, more than half of the patients in the observation arm did cross over to the azacitidine treatment arm. The primary efficacy end point was the overall response rate. Response consisted of complete or partial normalization of blood cell counts and of bone marrow morphology. The response rate in the azacitidine arm was about 16%; there were no responses in the observation arm. The response rates in the two single-arm studies were similar (13% and 19%). The responses were sustained, with median durations of 11 months and 17 months respectively. Responding patients who were transfusion dependent at study entry lost the need for transfusions. In addition, about 19% of patients had less than partial responses (termed improvement), and two-thirds of them became transfusion independent. Common adverse events associated with azacitidine treatment were gastrointestinal (nausea, vomiting, diarrhea, constipation, and anorexia), hematologic (neutropenia, thrombocytopenia), fevers, rigors, ecchymoses, petechiae, injection site events, arthralgia, headache, and dizziness. Liver function abnormalities occurred in 16% of patients with intercurrent hepatobiliary disorders and in two patients with previously diagnosed liver cirrhosis. Renal failure occurred in patients during sepsis and hypotension. There were no deaths attributed to azacitidine. Azacitidine, the first drug approved by the U.S. FDA for MDS, has a favorable safety profile and provides a clinical benefit of eliminating transfusion dependence and complete or partial normalization of blood counts and bone marrow blast percentages in responding patients.
 ...
PMID:FDA drug approval summary: azacitidine (5-azacytidine, Vidaza) for injectable suspension. 1579 20

(1) The first-line treatment for partial epilepsy is carbamazepine monotherapy; gabapentin monotherapy is an alternative, given its lower risk of drug-drug interactions. (2) The standard treatment for neuropathic pain associated with diabetes or post-herpetic neuralgia is a tricyclic antidepressant, with gabapentin as an alternative. Few drugs are available in this setting, and their efficacy is often modest. (3) Pregabalin is a GABA analogue closely related to gabapentin. Both drugs are marketed by Pfizer. Pregabalin has been approved for use in two indications: refractory partial epilepsy and neuropathic pain. (4) In patients with partial epilepsy inadequately controlled by a combination of two or possibly three antiepileptics, three placebo-controlled double-blind trials lasting 12 weeks suggest that adjunctive pregabalin treatment, at a dose of 600 mg/day divided in two or three doses, at least halves the frequency of seizures in 50% of patients. Pregabalin has not been compared with other second-line antiepileptics. (5) In neuropathic pain, there are 12 double-blind placebo-controlled trials involving patients with diabetes or post-herpetic neuralgia. Depending on the trial, between one-third and one-half of patients treated with pregabalin at a dose of 600 mg/day given in two or three doses had at least a 50% reduction in their pain score. In the only trial that included a group treated with amitriptyline (75 mg/day), the latter was significantly more effective than placebo, while pregabalin was not. (6) There are no comparative trials of pregabalin after amitriptyline and gabapentin failure. (7) The adverse effects profile of pregabalin is similar to that of gabapentin, and includes mainly neuropsychological reactions (dizziness and drowsiness). (8) Pregabalin, like gabapentin, can lead to weight gain and peripheral oedema especially in elderly patients. (9) Cases of visual field restriction have been reported with pregabalin in clinical trials. Animal studies suggest a possible risk of haemangiosarcoma, although no human cases have yet been described. (10) Pregabalin, like gabapentin, is eliminated unchanged in urine, implying a limited risk of interactions involving cytochrome P450, and suggesting that the dose should be reduced in patients with even moderate renal failure (creatinine clearance below 60 ml/min). (11) In practice, pregabalin offers nothing new for patients with partial epilepsy, for whom several other antiepileptics are available. The few available treatments for neuropathic pain have limited efficacy, and pregabalin may therefore be tried when both tricyclics and gabapentin fail. However, it is in no way certain that pregabalin is effective in such patients, and comparative trials are lacking.
 ...
PMID:Pregabalin: new drug. Very similar to gabapentin. 1639 76

Fabry's disease corresponds to an inherited disorder transmitted by an X-linked recessive gene. It generates a dysfunction of glycosphingolipid metabolism due to an enzymatic deficiency of alpha-galactosidase activity, resulting in glycosphingolipid deposits in all areas of the body. The clinical (heart, kidney, and central nervous system) manifestations are more severe in hemizygous boys than in heterozygous girls. They appear during childhood or adolescence: acroparesthesia, joint pain, angiokeratoma, corneal dystrophy, hypohydrosis or anhydrosis, and renal failure. The otoneurologic symptoms consist of hearing fluctuation, progressive unilateral or bilateral hearing loss, and episodes of vertigo or dizziness. Otoneurologic findings in 12 of 26 members of the same family are presented: the mother and 9 of her 12 children, as well as 2 of her 14 grandchildren: 4 healthy persons, 4 heterozygous female carriers, and 4 hemizygous male patients. Three of the male patients had fluctuation of hearing, sudden hearing loss, and episodes of vertigo and dizziness. The otoneurologic examinations showed a bilateral cochleovestibular deficit (n = 1), a right cochleovestibular deficit (n = 1), and a bilateral hearing loss combined with a right vestibular deficit (n = 1). Histopathologic evidence of glycosphingolipid accumulation in vascular endothelial and ganglion cells, as well as atrophy of the stria and spiral ligament, might explain the otoneurologic symptoms and findings.
 ...
PMID:Fabry's disease: otoneurologic findings in twelve members of one family. 1680 71

Neurologic signs and symptoms are common in acute malarial infection. However, after the parasites have been cleared from the blood and patients recover full consciousness, neurologic or psychiatric symptoms may occur or recur within 2 months after the acute illness. This phenomenon is called "postmalaria neurologic syndrome" (PMNS). We present a 50-year-old man who returned from the Republic of Malawi and soon developed Plasmodium falciparum malaria. Cerebral malaria, renal failure, hepatic failure, diffuse intravascular coagulation with thrombocytopenia, and upper gastrointestinal bleeding were noted during the acute stage. He was admitted to the infectious diseases ward and treated for 3 weeks. He was free from clinical general symptoms and parasites in blood smear when discharged. However, 2 weeks after discharge, he began to experience severe headache, dizziness, diplopia, mild hand tremor, unsteady gait, and easy falling. When readmitted to the neurologic ward, he presented with irritability, delirium, visual hallucination, and strange behavior. Neurologic examination was normal except for mild general weakness and evident truncal ataxia when walking. Brain magnetic resonance imaging revealed no structural lesions, and electroencephalography showed diffuse cortical dysfunction. Cerebral spinal fluid profile exhibited cytoalbuminologic dissociation. Brain single photon emission computed tomography showed diffuse cerebral parenchymal disorder. Nerve conduction studies revealed early sensory predominant polyneuropathy. The unsteadiness persisted for the initial 2 weeks of hospitalization until corticosteroid was administered. Intravenous methylprednisolone (80 mg/day) was continued for 3 days, followed by oral prednisolone (45 mg/day). His unsteadiness improved gradually after medication, and he absconded from the hospital on the 9th day of corticosteroid treatment with clear consciousness and free ambulation. The manifestation of PMNS is diverse and may present as an acute confusional state or psychosis, generalized seizure, fine tremors, cerebellar syndromes, postural hypotension, or malarial polyneuritis. Although the neurologic syndrome is primarily self-limited in most cases, corticosteroid may be beneficial in reversing PMNS.
 ...
PMID:Postmalaria neurologic syndrome: a case report. 1711 25

Oxycodone is a semi-synthetic opioid with an agonist activity on mu, kappa and delta receptors. Equivalence with regard to morphine is 1:2. Its effect commences one hour after administration and lasts for 12 h in the controlled-release formulation. Plasma halflife is 3-5 h (half that of morphine) and stable plasma levels are reached within 24 h (2-7 days for morphine). Oral bioavailability ranges from 60 to 87%, and plasma protein binding is 45%. Most of the drug is metabolised in the liver, while the rest is excreted by the kidney along with its metabolites. The two main metabolites are oxymorphone--which is also a very potent analgesic--and noroxycodone, a weak analgesic. Oxycodone metabolism is more predictable than that of morphine, and therefore titration is easier. Oxycodone has the same mechanism of action as other opioids: binding to a receptor, inhibition of adenylyl-cyclase and hyperpolarisation of neurons, and decreased excitability. These mechanisms also play a part in the onset of dependence and tolerance. The clinical efficacy of oxycodone is similar to that of morphine, with a ratio of 1/1.5-2 for the treatment of cancer pain. Long-term administration may be associated with less toxicity in comparison with morphine. In the future, both opioids could be used simultaneously at low doses to reduce toxicity. It does not appear that there are any differences between immediate and slow-release oxycodone, except their half-life is 3-4 h, and 12 h, respectively. In Spain, controlled-release oxycodone (OxyContin) is marketed as 10-, 20-, 40- or 80-mg tablets for b.i.d. administration. Tablets must be taken whole and must not be broken, chewed or crushed. There is no food interference. The initial dose is 10 mg b.i.d. for new treatments and no dose reduction is needed in the elderly or in cases of moderate hepatic or renal failure. Immediate-release oxycodone (OxyNorm) is also available in capsules and oral solution. Side effects are those common to opioids: mainly nausea, constipation and drowsiness. Vomiting, pruritus and dizziness are less common. The intensity of these side effects tends to decrease over the course of time. Oxycodone causes somewhat less nausea, hallucinations and pruritus than morphine.
 ...
PMID:Oxycodone: a pharmacological and clinical review. 1752 40

Gadolinium-based magnetic resonance imaging (MRI) contrast agents (Gad-CA) were formerly considered as alternatives to X-ray-employed iodinated media. Although originally thought to be nonnephrotoxic and proven to be nonhazardous in a healthy population, the Gad-CA safety issue is progressively more controversial in the high-risk group of end-stage renal disease (ESRD) patients. Recently, Gad-CAs have not only been blamed for harmless side effects such as dizziness or nausea but also for much more severe complications such as acute renal failure, pancreatitis, or even the development of so-called "nephrogenic systemic fibrosis" in patients with renal failure, culminating in the prohibition of gadodiamide (Omniscan) administration in ESRD patients and, due to renal-organ immaturity, in newborns and infants up to 1 year old. This editorial is written to give insights into the molecular structure of Gad-CAs as well as into the potential biochemical pathomechanisms underlying the aforementioned severe clinical manifestations. Furthermore, a review about the latest literature on Gad-CA nephrotoxicity is provided. Potential risk factors are mentioned and strategies to avoid deterioration of renal function are presented. Cases with Gad-CA-associated adverse events should be adequately documented and reported appropriately. MRI professionals should collaborate closely with their colleagues from other medical specialties to identify patients with adverse events.
 ...
PMID:Good MRI images: to Gad or not to Gad? 1757 78

Flecainide is a sodium channel blocker used mainly in the treatment of supraventricular arrhythmias. Central nervous system side effects such as dizziness, visual disturbances, headache and nausea are commonly associated with flecainide, but severe central nervous system toxicity is rare. We report the first case of flecainide toxicity in a patient with end-stage renal failure. Cessation of flecainide therapy resulted in a fall in serum flecainide levels, with associated resolution of adverse central nervous system effects. We also review the pharmacokinetics of flecainide in patients with chronic kidney disease.
 ...
PMID:Paranoid psychosis and myoclonus: flecainide toxicity in renal failure. 1837 17

Eszopiclone is the S-isomer of racemic zopiclone, a cyclopyrrolone with sedative-hypnotic activity that has been available in Europe, Canada, and Latin America since 1987. Eszopiclone acts by binding to the GABA(A) receptor. In contrast to the benzodiazepine (BZD) hypnotics, eszopiclone has more selectivity for certain subunits of the GABA(A) receptor. Oral eszopiclone is rapidly absorbed and extensively distributed to body tissues including the brain. Peak plasma concentrations are attained 1.0-1.6 hours after a 3 mg dose, while the mean elimination half-life is 6 hours. The half-life increases with age to about 9.0 hours in patients 65 years or older. Eszopiclone's pharmacokinetic (PK) profile is not substantially modified in patients suffering from renal failure or mild-to-moderate hepatic impairment, although patients with severe hepatic insufficiency should have a reduced dose. The subjective perception of improved sleep following eszopiclone 2 or 3 mg treatment has been demonstrated in randomized, double-blind, placebo-controlled studies of up to 6 months' duration. In these studies the drug significantly reduced sleep onset latency (SOL), the number of awakenings, and wake time after sleep onset (WASO) whereas total sleep time (TST) and quality of sleep were increased in non-elderly and elderly subjects. Sleep laboratory studies of the effects of eszopiclone have confirmed the drug's clinical efficacy in subjects with chronic primary insomnia. Eszopiclone, unlike BZD hypnotics, does not significantly alter values corresponding to slow wave sleep (SWS or stages 3 and 4) and rapid eye movement (REM) sleep. Rebound insomnia following withdrawal of eszopiclone has been examined in only one study. Discontinuation of the active treatment with 2 mg was followed by rebound insomnia in non-elderly subjects. Three-mg doses of eszopiclone administered for a period of up to 12 months was associated with a sustained beneficial effect on sleep induction and maintenance, with no occurrence of tolerance. The most common side-effects were unpleasant or bitter taste, headache, dyspepsia, pain, diarrhea, dry mouth, upper respiratory infection, urinary tract infection, dizziness, and accidental injury. New adverse events (withdrawal symptoms) including anxiety, abnormal dreams, hyperesthesia, nausea, and upset stomach were recorded in one study on the days following eszopiclone 2 or 3 mg discontinuation. Although dependence and abuse potential have not been formally assessed, unpublished data show that eszopiclone at doses of 6 and 12 mg produces euphoria effects similar to those of diazepam 20 mg in BZD drug addicts. In conclusion, available evidence tends to indicate that eszopiclone is effective and safe for the treatment of chronic primary insomnia in non-elderly and elderly subjects. Tolerance did not occur during active drug administration for a 12-month period. Thus eszopiclone can be efficacious not only during short- and intermediate-term administration but also in patients requiring prolonged regular drug usage.
 ...
PMID:Eszopiclone: its use in the treatment of insomnia. 1930 May 73


<< Previous 1 2 3 4 5 Next >>