Nervous System
Alzheimer's Disease
Donepezil (Aricept)
This is a new cholinesterase inhibitor was approved for the symptomatic treatment of Alzheimer's disease. Compared with placebo, in both 5 and 10 mg doses it appears to increase significantly cognitive function peaking 6 weeks after beginning of therapy. The improvement was maintained for 24 months with only a slight decrease in effectiveness. Side effects are generally mild including nausea, diarrhea, and vomiting and are rarely an indication for discontinuing the drug. These side effects can be minimized with a slow dose titration to maximum effect. Occasional episodes of dizziness occur with twice the frequency as with placebo.
Anticonvulsants
Topiramate (Topamax)
This is a new anti-seizure drug indicated for the treatment of partial onset seizures in adults and may be of value in the Lennox- Gastaut syndrome. Side effects include: weakness, back and leg pain, dizziness, and difficulty in concentrating. Patients on oral contraceptives should be warned that topiramate may reduce their effectiveness.
Tiagabine (Gabitril)
This antiepileptic drug is used adjunctive therapy in the treatment of complex partial seizures. Clinical studies showed a reduction of 13-32% in the number of seizures observed over a four week period. Side effects reported were similar to other antiepileptic medications and include abdominal pain, dizziness, weakness, nervousness, and difficulty in concentration.
Antipsychotics
Quetiapine (Seroquel)
This is a new antipsychotic drug specifically indicated for the treatment of schizophrenia. The clinical studies submitted to the FDA consisted of 6 weeks of therapy thus data for long term effectiveness are lacking at the present time. Comparative studies with placebo demonstrated significant improvement in BPRS measures and the CGI severity score. Side effects include: postural hypotension and drowsiness primarily at the start of therapy. Tardive dyskinesia can be expected but studies to date have failed to show a greater incidence than with placebo.
Olanzapine (Zyprexa)
This new antipsychotic is also indicated for the treatment of schizophrenia. The mechanism of action is not known. As quetiapine, it poessess many of the side effects of other agents used to treat psychosis. The long term use of olanzapine is still under investigation with 6 weeks representing clinical experience prior to FDA approval. There are virtually no drug interactions to be concerned with the concommittant use of other drugs. This drug has a low incidence of side effects with postural hypotension, constiipation, and dizziness being most common. Although this drug will produce akathesia (inability to perceive movement or position), the incidence of other extrapyramidal effects is no greater than placebo.
Migraine Headaches
Zolmitriptan
This is the second oral agent (following Imitrex) used in the treatment of migraine headaches. The mechanism of action is as a 5-hydroxytryptamine agonist. This results in vasoconstriction of intracranial bloofd vessels and termination of the migraine headache. The price is similar to Imitrex/tablet (Approx. $13 each) and its side effect patter is similar (tingling of extremities, chest pain, shortness of breath and swelling of the eyelids, lips and face.
Multiple Sclerosis
Tizanidine (Zanaflex)
An antispasmotic indicated in the management of increased muscle tone resulting from a spinal cord injury or multiple sclerosis. It is often used in conjunction with baclofen. Significant side effects include dizziness and fainting upon arising from a lying position (postural hypotension) and dry mouth. Liver function should be monitored frequently with initial therapy and every six months thereafter.
Glatiramer (Copaxone)
This injectable drug is indicated for the treatment of multiple sclerosis where it is believed to modify the immune process responsible for this disease. Clinical trials demonstrated that 56% of patients using glatiramer remained relapse free compared with 28% who received placebo. Over 80% of patients were progression free compared with 52% in the placebo group. After several months of treatment, additional injections often produce an immediate post-injection reaction including flushing, chest pain, palpitations, anxiety, and an urticara. This is usually self-limiting and does not require any specific therapeutic intervention.
Nausea and Vomiting
Dolasetron (Anzemet)
This drug is indicated for the prevention and treatment of nausea and vomiting which results from cancer chemotherapy and for postoperative nausea and vomiting. When given 1 hour prior to chemotherapy. It is available both as an injection and oral tablets. It is effective and approved both for adults and children. Occasionally, there is a prolongation of QT interval. This is usually self-limiting.
Scopolamine (Tranderm Scop)
This is an older drug used as a skin patch which is useful in preventing the signs and symptoms of motion sickness. It production was stopped in 1994 and has just resumed. Side effects are mild and include: dryness of the mouth, drowsiness, and blurred vision. It should not be used in conjunction with antihistamine antinauseants due to additive side effects.
Parkinsons Disease
Pramipexole (Mirapex)
This new drug is indicated for the treatment of Parkinsons disease. Clinical studues found a significant improvement of symptoms such as tremor and rigidity. This drug is usually used in combination with other drugs to treat this condition. Studies have also shown significant improvement in symptoms when added to existing therapy in patients with severe as well as early disease.
Ropinirole (Requip)
This oral dopamine agonist is indicated for the treatment of both early and advanced Parkinsons disease. When administered with levodopa, the dose of l-dopa may be reduced up to 30-40% with no loss of antiParkinsons disease activity. The most significant side efect is syncope with a slowed heart rate (bradycardia).
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