Amantadine effects

Low affinity use-dependent NMDA recqrtor antagonists meet the criteria for safe administration into patients. Drugs like amantadine and memantine have modest effects on Parkinson s disease and are used as initial therapy or as adjunct to l-DOPA. Their adverse effects include dizziness, lethargy and sleep disturbance. 

Amantadine is used cautiously in patients with seizure disorders, psychiatric problems, renal impairment, and cardiac disease. Amantadine is a Pregnancy Category B drug and is used cautiously during pregnancy and lactation. Concurrent use of antihistamines, phenothiazines, tricyclic antidepressants, disopyramide, and quinidine may increase the anticholinergic effects (dry mouth, blurred vision, constipation) of amantadine... 

AMANTADINE The nurse administers this drug for the prevention or treatment of respiratory tract illness caused by influenza A virus. Some patients are prescribed this drug to manage extrapyramidal effects caused by drugp used to treat Parkinsonism (See Chaps. 29 and 32). The nurse should protect the capsules from moisture to prevent deterioration. When the drug is administered for symptoms of influenza, it is important to start therapy within 24 to 48 hours after symptoms begin. 

Amantadine is less effective than levodopa in the treatment of Fhrkinson s disease but more effective than die anticholinergics. Amantadine may be given alone or in combination witii an antiparkinsonism drug witii anticholinergic activity. Amantadine is also used as an antiviral drug (see Chap. 14). 

In pharmacology, two adamantane derivatives. Amantadine (1-adamanta-neamine hydrochloride) and Rimantadine (a-methyl-1-adamantane methyla-mine hydrochloride) (see Fig. 24), have been well known because of their antiviral activity [129]. The main application of these drugs is prophylaxis (treatment to prevent the onset of a particular disease) and treatment of influenza-A viral infections. They are also used in the treatment of parkinsonism and inhibition of hepatitis-C virus. Memantine (1-amino-3,5-dimethyladaman-tane) (see Fig. 24) has been reported effective in slowing the progression of Alzheimer s disease [130]. 

The site of action for Memantine is the central nervous system (CNS) and it has CNS affinity. Amantadine and Rimantadine can penetrate to the CNS and cause some adverse effects. 

During known epidemics involving the influenza A virus, amantadine or rimantadine may be effective in minimizing associated symptomatology if administered early in the course of the disease. 

Amantadine is often effective for mild symptoms, especially tremor. It may also decrease dyskinesia at relatively high doses (400 mg/day). 

Amantadine is as efficacious as AChs and has less effect on memory. 

Bromocriptine, used in theory to reverse DA blockade, reduces rigidity, fever, or CK levels in up to 94% of patients. Amantadine has been used successfully in up to 63% of patients. Dantrolene has been used as a skeletal muscle relaxant, with favorable effects on temperature, respiratory rate, and CK in up to 81% of patients. 

Hall M, Brown Michael D (2005) Evidence-based emergency medicine/systematic review abstract. Are amantadine and rimantadine effective in healthy adults with acute influenza Ann Emerg Med 46 292-293... 

Keyset LA, Karl M, Nafziger AN, Bertino JS Jr. (2000) Comparison of central nervous system adverse effects of amantadine and rimantadine used as sequential prophylaxis of influenza a in elderly nursing home patients. Arch Intern Med 160 1485-1488... 

Amantadine is 70% to 90% effective in preventing illnesses caused by type A influenza viruses. 

CHF or peripheral edema Closely follow patients with a history of CHF or peripheral edema as there are patients who developed CHF while receiving amantadine. Glaucoma Because amantadine has anticholinergic effects and may cause mydriasis, do not give to patients with untreated angle closure glaucoma. 

K /Na exchange in distal tubule Dose Adults. 5-10 mg PO daily Peds. 0.625 mg/kg/d X in renal impair Caution [B, ] Contra T K, SCr >1.5 mg/dL, BUN >30 mg/dL, diabetic neuropathy Disp Tabs SE T K HA, dizziness, dehydration, impotence Interactions T Risk of hyperkalemia W/ ACEI, K-sparing diuretics, NSAIDs, K salt substitutes T effects OF Li, digoxin, antihypertensives, amantadine T risk of hypokalemia W/ licorice EMS Monitor ECG for signs of hyperkalemia (peaked T waves) T effects of digoxin OD May cause bradycardia, light-headedness, and syncope symptomatic and supportive... 

Hyoscyamine (Anaspaz, Cystospaz, Levsin, Others) [Antispasmodic/Anticholinergic] Uses Spasm w/ GI bladder disorders Action Anticholinergic Dose Adults. 0.125-0.25 mg (1-2 tabs) SL/PO tid-qid, ac hs 1 SR cap ql2h Caution [C, +] T Effects w/ amantadine, antihistamines, antimuscarinics, haloperidol, phenothiazines, TCA, MAOI Contra BOO, GI obst, NAG, MyG, paralytic ileus, ulcerative colitis, MI Disp Caps, tabs SE Dry skin, xerostomia, constipation, anticholinergic SE, heat prostration w/ hot weather Interactions T Effects W/ amantadine, antimuscarinics, haloperidol, phenothiazines,... 

Memantine (Namenda) [Anti Alzheimer Agent/NMDA Receptor Antagonist] Uses Mod/ evere Alzheimer Dz Action N-methyl-D-aspartate recqjtor antagonist Dose Target 20 mg/d, start 5 mg/d, t 5 mg/d to 20 mg/d, wait >1 wk before t dose use doses if >5mg/d Caution [B, /-] Hqjatic/mild-mod renal impair Disp Tabs, sol SE Dizziness Interactions t Effects W amantadine, carbonic anhydrase inhibitors, dextromethorphan, ketamine, Na bicarbonate t effects W/ any drug, herb, food that alkalinizes urine EMS Use NaHCOs w/ caution OD May cause restlessness, hallucinations, drowsiness, and fainting symptomatic and supportive... 

Rimantadine (Flumadine) [Antiviral] Uses Prophylaxis Rx of influenza A viral Infxns but not for HlNl swine flu Action Antiviral Dose Adults Feds >9 y. 100 mg PO bid Feds 2-9 y. 5 mg/kg/d PO, 150 mg/d max daily w/ severe renal/hepatic impair elderly initiate w/in 48 h of Sx onset Caution [C, -] w/ cimetidine avoid w/ PRG, breast-feeding Contra Component amantadine allergy Disp Tabs SE Orthostatic X BP, edema, dizziness, GI upset, X Sz threshold Interactions T Effects W/ cimetidine i effects W/ acetaminophen, ASA EMS Concurrent EtOH usage may result in light-headedness, confusion, syncope, and hypotension OD May cause N/V, tremors, Szs, anticholinergic Sxs, ventricular arrhythmias give IV fluids... 

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