PTCE: The Basics of Medications - Miscellaneous Medications

The table below provides additional information on the medications used to treat Alzheimer’s disease and Parkinson’s disease.

Alzheimer’s disease is a progressive neurological disorder that affects memory and cognition. Pharmaceutical drug therapy is focused on two main neurotransmitters: acetylcholine and glutamate, both of which are associated with memory and learning. Medications are aimed at inhibiting the breakdown of acetylcholine in order to improve patient symptoms and outcomes or are aimed at inhibiting the buildup of glutamate. The medications used to treat Alzheimer’s disease exert their therapeutic effect by enhancing cholinergic activity (donepezil, rivastigmine, tacrine), by inhibiting acetylcholinesterase (galantamine), by acting as antagonists for the N-methyl-D-aspartate (NMDA) receptor associated with glutamate production (memantine), or by using a combination of pathways to improve cholinergic activity. Common side effects for these agents include dizziness, confusion, diarrhea or constipation, fatigue, and headaches. Alzheimer’s medications are indicated for long-term control and treatment.
Parkinson’s disease is a progressive neurological disorder that affects movement. Early symptoms include tremors, stiffness, and slowness of movement. They are due to inactivity or a decrease in the neurotransmitter dopamine. Medications used for Parkinson’s are aimed at increasing the free levels of dopamine in the body by one of three mechanisms: acting as dopamine agonists (pramipexole, ropinirole), introducing exogenous dopamine (levodopa), or prolonging the effect of levodopa by acting as a catechol-O-methyltransferase (COMT) inhibitor (entacapone). Side effects of these agents may include nausea, orthostatic hypotension, and, in some cases, dyskinesia (involuntary movements resulting from the administration of large doses of levodopa). Patients are slowly weaned off these medications. Medication therapy is long-term.

Table: Alzheimer’s Disease and Parkinson’s Disease



 

Attention-deficit hyperactivity disorder (ADHD) is a chronic condition that affects attention and results in hyperactivity and impulsivity. Medications in this category are either classified as stimulants or as nonstimulants. Stimulant drugs (e.g., lisdexamfetamine, dexmethylphenidate) increase the levels of dopamine, which is a neurotransmitter associated with mood, motivation, pleasure, and attention.

These agents may cause restlessness, insomnia, loss of appetite, personality changes, and mood swings. There is also a potential for abuse and psychiatric problems, including depression and paranoia. Nonstimulant agents work to increase the levels of the neurotransmitter norepinephrine (atomoxetine). Atomoxetine (Strattera) may cause somnolence, mood swings, and, in some cases, suicidal ideations.

Table: Attention-Deficit Hyperactivity Disorder (ADHD)

 

The treatment of bipolar disorder involves a combination of mood-stabilizing drugs and psychotherapy. Several types of bipolar disorder exist. Treatment depends on the diagnosis as well as on the symptoms present. Schizophrenia is a complex brain disorder that often results in an altered perception of reality. The selection of appropriate medications is based on the symptoms present. Symptoms are often categorized as positive (symptoms shown in excess, like hallucinations or delusions) or as negative (symptoms that are deficient, like social withdrawal or flat affect). Traditional antipsychotics are an older class of medications that are used to treat only positive symptoms. This class includes medications like fluphenazine and haloperidol, which have a potential to cause tardive dyskinesia (involuntary, repetitive body movements) and extrapyramidal side effects (antipsychotic drug side effects resulting in parkinsonism and abnormal involuntary movement, often referred to as acute dyskinesia). Atypical antipsychotics are used to treat both positive and negative symptoms. Agents in this class include olanzapine and risperidone. These agents cause less extrapyramidal side effects and are generally used more often than traditional agents.

Table: Bipolar Disorder and Schizophrenia

 

Gout is a form of arthritis caused by an excess of uric acid in the blood. Too much uric acid can cause the formation of crystals in joints, often presenting as pain, stiffness, and swelling. Medications in this category aim at reducing uric acid levels. Uricosuric agents, like probenecid, increase the elimination of uric acid by the kidneys. These agents are contraindicated in patients with uric acid kidney stones and hypersensitivities. The xanthine oxidase inhibitor allopurinol exerts its action by inhibiting the conversion of hypoxanthine to uric acid. Patients should be monitored for the presence of an allergic reaction and the potential for hepatotoxicity. Uricosuric agents and xanthine oxidase inhibitors are used long-term to reduce uric acid levels. Colchicine is indicated for acute flare-ups and may cause gastrointestinal upset.

Table: Gout

The most common class of medications used to treat migraines is the 5-HT1 receptor agonists, often referred to as the “triptans” because they end in the USAN stem “triptan.” These agents constrict blood vessels and reduce inflammation by targeting serotonin at the 5-HT1 receptor. These medications are used at the onset of symptoms and may cause asthenia (abnormal weakness), dizziness, and somnolence.

A new class of medications called the “ditans” is also indicated in the treatment of acute migraines. This class targets the 5-HT1F receptor, treating acute migraines without causing blood vessel constriction.

Table: Migraines

 

Smoking cessation agents are aimed at helping patients quit using tobacco. Bupropion exerts its primary effect by inhibiting dopamine reuptake by neuronal cells. The main side effects include insomnia and dry mouth. Bupropion may lower the seizure threshold and should be taken cautiously with other agents that may have similar effects. Varenicline is a nicotine agonist that prevents nicotine stimulation. Neuropsychiatric symptoms, such as depression and suicidal ideations, have been reported. A potential for nausea, seizures, and hypersensitivity is also possible while taking varenicline. Many nicotine replacement products are available over-the-counter. These agents are used to give the body nicotine, thus, reducing withdrawal symptoms. Side effects are usually mild and cease upon cessation of therapy. Pregnant patients and those with a history of cardiovascular disease should consult their physician before initiating therapy.

Table: Smoking Cessation

Summary - Having an understanding of pharmacology is a fundamental component of pharmacy practice.
- Drug interactions can occur for a variety of reasons, including as a result of changes in metabolism, absorption, and excretion.
- Pharmacy technicians should be able to identify commonly prescribed medications, including the drug class, indication, common strengths, side effects, and duration of therapy.
- Drug endings may have similarities within a classification. Memorizing specific prefixes and suffixes may help you remember a drug class or an indication and is a great way to remember medications.
- Medication dosing parameters are based on the therapeutic index. Medications with a narrow therapeutic index will require frequent monitoring to ensure that blood concentrations are within therapeutic limits.
- Proper storage of medications is crucial to preserve the original potency, to advise about proper adherence, and to maintain safety.