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1?line for the last three years. The bromocriptine led to backaches (fibrosis?) so I tried Permax which did nothing for me. I mentioned Clinical Pharmacology recently as a source of good drug info but neglected to give the e-mail address for Gold Standard Multimedia. It is [log in to unmask] It is the source of the following info on amantadine. Description: Amantadine is a synthetic antiviral agent. It was introduced as an agent for prophylaxis of influenza A and was later found to cause symptomatic improvement in parkinsonism. It is used for the prophylactic or symptomatic treatment of influenza A virus, especially for high-risk patients such as those in critical public-service positions, immunosuppressed patients, nursing home residents, contacts of high-risk patients, and those with severe influenza A viral infection. Although it inhibits replication of all types of the influenza A virus, it should not be used as a substitute for vaccination. Rimantadine is a related antiviral compound that reaches higher concentrations in respiratory secretions after oral administration and has fewer CNS effects. Amantadine was approved by the FDA in 1966. Mechanism of Action: Amantadine's mechanism of action is not fully understood. Antiparkinsonian actions are unrelated to the antiviral effects. Amantadine appears to potentiate CNS dopaminergic responses. It may release dopamine and norepinephrine from storage sites and inhibit the reuptake of dopamine and norepinephrine. Amantadine is clearly less effective than levodopa but can offer additional benefit in patients experiencing maximal or waning effects from levodopa. As an antiviral, amantadine can inhibit viral replication within the viral cell. Amantadine appears to block the uncoating of the virus particle and subsequent release of viral nucleic acid into the host cell. It also may interfere with penetration of the cell wall by adsorbed virus. To prevent a viral infection, the drug should be present before exposure to the virus, but, if given within 24 48 hours of onset of symptoms, the influenza may be less severe. Pharmacokinetics: Amantadine is administered orally. Absorption from the GI tract appears to be rapid and complete. Bioavailability is 86% in the elderly and greater than 90% in young adults.EEE Peak plasma concentrations are achieved in about 2 4 hours following oral administration. Steady-state concentrations following daily dosage are obtained in 2 4 days. Amantadine crosses the blood-brain barrier and the placenta; distributes into tears, saliva, and nasal secretions; and is excreted into breast milk. Ninety percent of amantadine is excreted in the urine via glomerular filtration and tubular secretion. Renal impairment reduces protein binding. The elimination half-life in patients with normal renal function is about 11 15 hours but can be as long as 7 10 days for those with severe renal impairment. Half-life in elderly patients is 24 29 hours. Acidifying the urine increases the rate of excretion. Only a small amount of amantadine is removed by dialysis. Patrick J. Martin ([log in to unmask]) Pharmacokinetics: Amantadine is administered orally. Absorption f