Central blurring

Inorganic chemistry is facing an identity crisis. The old jumble of facts has given way to the new jumble of theories. Worse still the distinction between fact and theory itself has been allowed to blur. Inorganic chemists have been coaxed away from their formerly strong, central position based on a monopoly of information on syntheses, reactions, and properties of the elements and their compounds by the more ephemeral allure and false sophistication of spectroscopy and theory. 

Antidepressants Noradrenaline/5-HT transporters Na+, K+ channels l Noradrenaline/ 5-HT reuptake l Na+ currents t K+ currents l Excitability of peripheral and central neurons Cardiac arrhythmia, myocardial infarction, sedation, nausea, dry mouth, constipation, dizziness, sleep disturbance, blurred vision... 

Central nervous system-headache, apathy, drowsiness, visual disturbances (blurred vision, disturbance in yellow/green vision, halo effect around dark objects), mental depression, confusion, disorientation, delirium... 

The ammonia produced by enteric bacteria and absorbed into portal venous blood and the ammonia produced by tissues are rapidly removed from circulation by the liver and converted to urea. Only traces (10—20 Ig/dL) thus normally are present in peripheral blood. This is essential, since ammonia is toxic to the central nervous system. Should portal blood bypass the liver, systemic blood ammonia levels may rise to toxic levels. This occurs in severely impaired hepatic function or the development of collateral links between the portal and systemic veins in cirrhosis. Symptoms of ammonia intoxication include tremor, slurred speech, blurred vision, coma, and ultimately death. Ammonia may be toxic to the brain in part because it reacts with a-ketoglutarate to form glutamate. The resulting depleted levels of a-ketoglutarate then impair function of the tricarboxylic acid (TCA) cycle in neurons. 

The ionic atmosphere has a blurred (diffuse) structure. Because of thermal motion, one cannot attribute precise locations to its ions relative to the central ion one can only dehne a probability to find them at a certain point or define a time-average ionic concentration at that point (the charge of the ionic atmosphere is smeared out around the centraf ion). In DH theory, the interaction of the central ion with specific (discrete) neighboring ions is replaced by its interaction with the ionic atmosphere (i.e., with a continuum). 

Painless, progressive moderate to severe blurring of central vision... 

Use of diethylpropion for a period longer than 3 months is associated with an increased risk for development of pulmonary hypertension. When used as directed, reported common central nervous system adverse effects included overstimulation, restlessness, dizziness, insomnia, euphoria, dysphoria, tremor, headache, jitteriness, anxiety, nervousness, depression, drowsiness, malaise, mydriasis, and blurred vision. In addition, diethylpropion can decrease seizure threshold, subsequently increasing a patient s risk for an epileptic event. Other organ systems also can adversely be affected, resulting in tachycardia, elevated blood pressure, palpitations, dry mouth, abdominal discomfort, constipation,... 

Anticholinergic side effects include dry mouth, blurred vision, constipation, and urinary retention. More serious reactions include forgetfulness, sedation, depression, and anxiety. Patients with preexisting cognitive deficits and the elderly are at greater risk for central anticholinergic side effects. 

The toxins affect the central nervous system (CNS). Symptoms start within twenty minutes and may last for two to four hours, but peak hallucinogenic activity rarely lasts for more than one hour. Symptoms include anxiety and tension, visual effects such as blurring, euphoria, increased color perception with closed eyes, but also headache and fatigue. The overall sensation is usually described as pleasant. 

Scopolamine. Is a central nervous system depressant that can cause excitement, blurred vision, urinary retention, and severe hallucinations. The dose is around to 1 mg and should be used with caution. Scopolamine has been used to treat Parkinson s disease with good success. 

The clinical picture of carbaryl intoxication results from inactivation of cholinesterase, resulting in the accumulation of acetylcholine at synapses in the nervous system, skeletal and smooth muscle, and secretory glands. Signs and symptoms of overexposure may include (1) muscarinic manifestations such as miosis, blurred vision, lacrimation, excessive nasal discharge or salivation, sweating, abdominal cramps, nausea, vomiting, and diarrhea (2) nicotinic manifestations including fasiculation of fine muscles and tachycardia and (3) central nervous system manifestations characterized by headache, dizziness, mental confusion, convulsions, coma, and depression of the respiratory center. 

Ocular formulations of pilocarpine have caused visual blurring that may result in decreased visual acuity, especially at night and in patients with central lens changes, and impairment of depth perception. Advise caution while driving at night or performing hazardous activities in reduced lighting. 

Retinopathy - Reading and seeing difficulties (ie, words, letters, or parts of objects missing) photophobia blurred distance vision missing or blacked out areas in the central or peripheral visual field light flashes and streaks. 

Methocarbamol (Robaxin) [Skeletal Muscle Relaxant/ Centrally Acting] Uses Relief of discomfort associated w/ painful musculoskeletal conditions Action Centrally acting skeletal muscle relaxant Dose Adults. 1.5 g PO qid for 2-3 d, then 1-g PO qid maint therapy IV form rarely indicated Peds. 15 mg/kg/dose IV, may repeat PRN (OK for tetanus only), max 1.8 g/mVd for 3 d Caution Sz disorders [C, +] Contra MyG, renal impair Disp Tabs, inj SE Can discolor urine drowsiness, GI upset Interactions T Effects Wf CNS depressant, EtOH EMS May cause blurred vision and orthostatic hypotension use caution w/ CNS depressants concurrent EtOH use can T CNS depression OD May cause drowsiness, light-headedness, syncope, and slow shallow breathing symptomatic and supportive... 

Monoamine Oxidase A MAOA Inhibition May induce severe hypertensive crisis (known as the Cheese reaction ) - Centrally mediated side effects such as the serotonin syndrome, dizziness, blurred vision and weakness. 

Geriatric Considerations - Summary Glycopyrrolate does not cross the blood-brain barrier so is less likely to cause the central effects seen with anticholinergics such as atropine. Other anticholinergic side effects such as blurred vision, dry mouth, urinary retention, and constipation do occur and can limit the usefulness of this drug in the older adult. 

Anticholinergic side effects are categorized as peripheral or central. The most common peripheral side effects are dry mouth, decreased sweating, decreased bronchial secretions, blurred vision, difficulty with urination, constipation, and tachycardia. Bethanechol chloride, a cholinergic drug that does not cross the blood-brain barrier, may effectively treat these side effects at a dosage of 25-50 mg three times a day. 

Antihistaminics are better tolerated by elderly patients who do not tolerate anticholinergics. Antihistaminics do not cause blurring of vision and xerostomia and also possess some central anticholinergic properties. 

The adverse reactions are due to the peripheral muscarinic blockade and central actions. The general side effects include dry mouth, difficulty is swallowing, thirst, dry skin, skin rash, flushed skin etc. It also produces constipation, urinary retention, impotence, difficulty in micturition, tachycardia, palpitation, postural hypotension, dilatation of pupil, photophobia, blurred vision, dizziness, fatigue, anxiety and tremors etc. 

The irritant effect of acetaldehyde vapour, which is reported to cause coughing and a burning sensation in the nose, throat and eyes, usually prevents exposure to a level sufficient to cause depression of the central nervous system. A splash of liquid acetaldehyde was reported to cause a burning sensation, lachrymation and blurred vision. Prolonged periods of contact with the skin result in erythema and bums repeated contact may result in dermatitis, due either to primary irritation or to sensitization. 

Antimuscarinic drugs have a number of central nervous system effects, including drowsiness, mental slowness, inattention, restlessness, confusion, agitation, delusions, hallucinations, and mood changes. Other common effects include dryness of the mouth, blurring of vision, mydriasis, urinary retention, nausea and vomiting, constipation, tachycardia, tachypnea, increased intraocular pressure, palpitations, and cardiac arrhythmias. Dyskinesias occur in rare cases. Acute suppurative parotitis sometimes occurs as a complication of dryness of the mouth. 

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