Amantadine dosage

Observational studies In a retrospective observational study of 11 patients receiving amantadine for the treatment of Parkinson s Disease three patients reported side effects. Lower extremity oedema was reported in an 86-year-old man receiving amantadine (100 mg twice daily) after 5 months of treatment. This resolved when amantadine was discontinued. Hallucinations were reported in a 71-year-old man in the first 2 months of treatment with amantadine. A reduction in amantadine dosage from 100 mg twice daily to 100 mg once daily did not result in improvement and the drug was therefore discontinued, which resulted in resolution of symptoms. 

Suggested Dosage Guidelines for Amantadine in Impaired Renal Function... 

Neuroleptic malignant syndrome (NMS) Sporadic cases of possible NMS have been reported in association with dose reduction or withdrawal of amantadine therapy. Observe patients carefully when the dosage of amantadine is reduced abruptly or discontinued, especially if the patient is receiving neuroleptics. 

Amantadine is less efficacious than levodopa, and its benefits may be short-lived, often disappearing after only a few weeks of treatment. Nevertheless, during that time it may favorably influence the bradykinesia, rigidity, and tremor of parkinsonism. The standard dosage is 100 mg orally two or three times daily. Amantadine may also help in reducing iatrogenic dyskinesias in patients with advanced disease. 

The pharmacologic basis of these disorders is unknown, and there is no satisfactory medical treatment for them. A subset of patients respond well to levodopa medication (dopa-responsive dystonia), which is therefore worthy of trial. Occasional patients with dystonia may respond to diazepam, amantadine, antimuscarinic drugs (in high dosage), carbamazepine, baclofen, haloperidol, or phenothiazines. A trial of these pharmacologic approaches is worthwhile, though often not successful. Patients with focal dystonias such as blepharospasm or torticollis often benefit from injection of botulinum toxin into the overactive muscles. The role of deep brain stimulation for the treatment of these conditions is being explored. 

The primary adverse effects associated with amantadine are orthostatic hypotension, CNS disturbance (e.g., depression, confusion, hallucinations), and patches of skin discoloration on the lower extremities (livedo reticularis). However, these side effects are relatively mild compared to those of other anti-Parkinson drugs and are usually reversed by altering the drug dosage. 

Avian Influenza. Of the four medications licensed for treatment, only Zanamavir (Relenza) is approved for treatment in patients 7 years of age and older (Lee Krilov, 2005). The dose in children 7 years of age or younger is 10 mg (two inhalations) via Diskhaler every 12 hours for 5 days, starting within 48 hours of symptom onset (Lee Krilov, 2005). However, Zanamavir is not approved for prophylaxis against influenza A (Lee Krilov, 2005). Amantadine (Symmetrel) and Oselta-mavir (Tamiflu) have pediatric dosages for treatment and prophylaxis (see Lee Krilov, 2005, p. 50), but they are not approved. 

Repeat treatment After a repeat treatment had been decided on, increased dosage and prolonged duration of IFNa (237) or consensus IFN (160) were used. Other possible combinations were applied, such as IFNa + thymosin (236), IFNa + cyclosporin (223, 228), IFNa + UDCA (230) or IFNa + amantadine (250). In all these studies, positive results and an improvement in quality of life quality were described for some patients. Even iron removal can be used as an additional measure. (217, 243) Likewise, good results in some patients have also been achieved with immunostimulants or adjuvant sub-... 

Memantine is an amantadine derivative that has been studied in patients with Parkinson s disease. Its adverse effects include agitation, restlessness, insomnia, pronounced delirious states, and muscular hypotonia. All were reversible after dosage reduction or withdrawal. 

C) Dosage modification of amantadine is required in renal insufficiency... 

Amantadine can enhance the response of the other PD medications and is given in the same dosage as if given alone. 

Since its hepatic metabolism is minimal amantadine would not be expected to interact with other drugs. However, it has been shown to increase morphine levels, probably by interfering with 3-glucuro-nidation in the kidneys. Thus, amantadine may reduce the dosage of morphine required for pain relief when administered with this opioid. 

Amantadine may exacerbate central nervous system effects in disorders. Dosages must be adjusted for patients with renal disease or congestive heart failure. Since amantadine interacts with morphine caution is required when these two drugs are administered together. 

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