Pharmacology and Nutrition

Learning Outcomes

At the end of the topic, students should be able to;

1.     Explain the common drug use in nervous system.

2.     Differentiate drugs between stimulants and depression for CNS.

3.     Explain nursing responsibilities when administering drug use in CNS.

 

CNS STIMULANTS

May produce dramatic effects by increasing the activity of CNS neurons.

Their therapeutic usefulness is limited because of their many general effects & side effects in the body

Can result to drug tolerance, drug dependence & drug abuse problems

Medically approved is limited to:

* Attention deficit hyperactive disorder (ADHD), NARCOLEPSY, OBESITY, Reversal of RESPIRATORY DISTRESS

Major groups:

1.   Amphetamine – stimulate cerebral cortex (anti-ADHD and anti-narcoleptic) 

Mechanism of action & drug effects:

Stimulate areas of the brain associated with mental alertness (cerebral cortex and thalamus)

Mimics SNS

CNS effects: mood elevation or euphoria; increased mental alertness and capacity for work; decreased fatigue and drowsiness and prolonged wakefulness    

Respiratory effects: relaxation of bronchial smooth muscles; increased respiration and dilation of pulmonary arteries

CNS stimulants are potent drugs with a strong potential for tolerance and psychological dependence.

=> Classified as Schedule II under the Controlled Substance Act   

 

NURSING RESPONSIBILITIES:

Should not be given in the evening or before bedtime because insomnia may result.

Monitor for tolerance and dependence

Monitor for drug abuse

Caffeine containing foods should be avoided

Food affects absorption rate

Instruct not to abruptly discontinue the drug to avoid withdrawal symptoms

 

2.  Anorexiants- acts on cerebral cortex & on hypothalamus to suppress appetite

Mechanism of actions and drug effects

Suppress appetite control centers in the brain

Increase body’s basal metabolic rate: mobilization of adipose tissue stores and enhanced cellular glucose uptake and reduce dietary fat absorption

General Use: 

used in the management of exogenous obesity as part of a regimen including a reduced caloric diet and exercise

Used in obese patients with a BMI of 30 or more; patients with BMI of 27 who are hypertensive or have high cholesterol or diabetes

Nursing Implications

Monitor weight and dietary intake prior to and periodically during therapy.

Advise patient that regular physical activity, approved by health care professional, should be used in conjunction with medication and diet.

       

3.  Analeptics – acts on brainstem & medulla to stimulate respiratory center

Mode of action: Mostly stimulates the brainstem, spinal cord & cerebral cortex; inhibits the enzyme phosphodiesterase

Uses and Considerations:  Used for newborns with apnea to stimulate respiration. Given through an NGT.

Nursing Implications

Assess blood pressure, pulse, respiration, lung sounds, and character of secretions before and throughout therapy.

History of cardiovascular problems should be monitored for ECG changes and chest pain.

Administer around the clock to maintain therapeutic plasma levels

 

CNS DEPRESSION

Drugs causing CNS depression are classified as: sedatives or hypnotics

- Sedatives reduce nervousness, excitability and irritability without causing sleep.

-  Hypnotics cause sleep and have a much more potent effect on the CNS than sedatives

1.Sedative-Hypnotics

The mildest form of CNS depression is sedation

Diminishes physical and mental responses at lower dosages of certain CNS depressants (does not affect consciousness).

Increasing the drug dose can produce a hypnotic effect – not hypnosis but a form of “natural” sleep.

With very high doses of sedative-hypnotic drugs, anesthesia may be achieved.

There are short-acting hypnotics and intermediate-acting hypnotics: Short-acting hypnotics= useful in achieving sleep-> allow client to awaken early in the morning.

- Intermediate-acting hypnotics= useful for sustaining sleep

The ideal hypnotic promotes natural sleep without disrupting normal patterns of sleep and produces no hangover or undesirable effect.

Hypnotic drug therapy should be short term to prevent drug dependence and drug tolerance

Classified chemically into three main groups:

1. Barbiturates

Mechanism of Action and Drug Effects:

- acts primarily on the brainstem (reticular formation)

- hinders movement of impulses from the thalamus to the cerebral cortex creating depression in the CNS which can range from mild to severe

=> travel of impulses is inhibited due to its ability to potentiate GABA (primary inhibitory neurotransmitter of the brain)

Indications

All barbiturates have the same effect but differ in potency, time to onset of action and duration of action

Used as hypnotics, sedatives, anticonvulsants and anesthesia during surgical procedures

Therapeutic uses:

Ultrashort acting: anesthesia for short surgical procedures, anesthesia induction, control of convulsions, and reduction of ICP in neurosurgical patients

Short acting: sedation/sleep induction and control of convulsive conditions

Intermediate acting: sedation/sleep and control of convulsive conditions

Long acting: sleep induction, epileptic seizure prophylaxis

Nursing Implication:

* Because these drugs are taken approximately 1 hour for the onset of sleep, they are not prescribed for those who have trouble getting to sleep.

* Vital signs should be closely monitored in persons who take intermediate-acting barbiturates.

2. Benzodiazepines

Have anxiolytic & hypnotic dose related effects

More preferred than Barbiturates because:

1. prevents anxiety without causing much associated sedation.

2. less likely to cause dependence

Increased anxiety might be the cause of insomnia for some clients, so the following can be used to alleviate anxiety:

1. lorazepam (Ativan)

2. diazepam (Valium)

 

2. ANTICONVULSANTS; Also called antiepileptics

Goal: to suppress the rapid and excessive firing of neurons that start a seizure

 *An excellent anticonvulsant would have few serious side effects. However, no such drug exists.

Action: Inhibit neuromuscular transmission

Uses: -

Long-term management of chronic epilepsy or recurrent seizures

Short-term management of acute isolated seizures not caused by epilepsy, such as after trauma or brain surgery.

Used in the emergency treatment of status epilepticus

Five Major Classes

Barbiturates

Benzodiazepines

Hydantoins

Iminostilbenes

Valproic acid

 

Assessment:

 1. thorough patient history is necessary to identify the type of seizure disorder

2. Additional patient information: family history of seizures (if any) and recent drug therapy

3. other information needed:  history of a head injury or a thorough medical history

4. Baseline vital signs data

5. Laboratory and diagnostic tests (EEG, CT scan, CBC, hepatic and renal tests)

6. On-going assessment:

6.1 May require frequent dose adjustments during the initial treatment period

6.2 Regular serum plasma levels of anticonvulsant are monitored for toxicity

6.3 Carefully document each seizure:

- time of occurrence        

- length of the seizure 

- psychic or motor activity occurring before, during, and after the seizure.

 

Analgesics are drugs that relieve pain without causing loss of consciousness. Although the proper analgesic may be extremely valuable in pain treatment, it is important to remember that complete masking of a pain symptom may not be desirable; masking can eliminate an important means of monitoring the progress of the underlying disease. Selection of the proper analgesic is generally based on six factors: effectiveness of the agent, duration of action, desired duration of therapy, ability to cause drug interactions, hypersensitivity of the client, and available routes of drug administration.

OPIOID ANALGESICS

Among the most potent analgesics now available are those derived from opium, a substance which is secreted from the unripe seed capsules of a species of poppy grown mostly in Turkey, India, China, and Iran. Opium has been used for thousands of years to alleviate pain and produce a sense of detachment and well-being (euphoria).

However, it was not until the sixteenth century that opium’s major component, morphine, was isolated. In the following years, many additional analgesics were naturally or synthetically derived from opium or were designed to mimic the pharmacological actions of opiate compounds. All of these agents became collectively known as the opioids or opioid analgesics.

Opioid analgesics, of which morphine is usually considered to be the prototype drug, exert a number of pharmacological actions. They are employed clinically primarily for their ability to produce analgesia. Opioids are primarily used in the treatment of moderate-to-severe pain originating from visceral sources (i.e., from the GI tract and other internal organs).

Morphine sulfate is the drug of choice for moderate-to-severe pain in children, such as postoperative pain. Some of these agents are also employed as cough suppressants and in suppressing the motility and secretion-forming ability of the gastrointestinal tract.

All of the narcotic analgesics are capable of causing dependence with regular use and are classified as controlled substances by the federal government.

Note: Do not administer opioid analgesics to clients with depressed respirations.

Severe respiratory depression that results from opioid use can be treated with naloxone (Narcan) given IV.

Instruct client to avoid activities requiring mental alertness.

Routinely evaluate the effectiveness of opioid analgesics in relieving pain.

Supportive nursing measures should be used to enhance the effectiveness of opioid analgesics (e.g., massage, positioning, emotional support, diversion, guided imagery).

Assess pain for type, location, and intensity before and 10–45 minutes after administration.

 

NONOPIOID ANALGESICS

Buprenorphine HCl (Buprenex), butorphanol tartrate (Stadol), nalbuphine hydrochloride (Nubain) and pentazocine hydrochloride (Talwin) were also developed to provide effective analgesic action without the abuse potential of the opioid analgesics. It has become evident that all of these agents exert some opioid antagonist activity. If they are administered to an opioid-dependent client, therefore, they may induce the development of withdrawal symptoms. Although none of these agents were initially believed to be capable of being abused, abuse of pentazocine has been frequently reported in recent years. As a result, this agent has been classified as a controlled substance by the federal government.

Note: Administer before pain becomes severe.

Assess client’s response to drug.

Be aware of possibility of dependency.

Supportive nursing measures (e.g., positioning, emotional support) should be used to enhance the effectiveness of these drugs.

early childhood socialization, and past experiences with pain. For example, older persons often tolerate chronic pain because they believe it is a natural occurrence in growing older. These factors must be taken into account when assessing pain.

KEY NURSING IMPLICATIONS:

1. Pain-relieving measures include positioning, massage, distraction, and use of analgesics.

2. Assess the onset, location, duration, intensity, and nature of pain, as well as other symptoms associated with the pain.

3. If the client is unable to provide information about pain, obtain information from the family and observe the patient for such signs of pain as anxiety, restlessness, and changes in vital signs.

4. Response to pain depends on the client’s developmental level, sex, ethnic group membership, early childhood socialization, and past experiences with pain.

5. Analgesics are most effective when given before pain becomes severe. 6. Do not undertreat pain because of a fear of producing drug addiction.

KEY NURSING IMPLICATIONS

Aspirin and Acetaminophen

1. Aspirin is contraindicated in persons taking anticoagulants, those with gastric ulcers, pregnant women, and children with febrile illness, such as flu.

2. Aspirin allergy must be noted on the client’s chart and medication record, and the client is instructed to avoid nonprescription drugs containing aspirin.

3. Use of aspirin in children has dramatically declined because of its most frequent use as an antipyretic, and it has been determined that aspirin should not be given with febrile illness caused by viruses.

4. Instruct the client to take sufficient fluid with aspirin to ensure that the tablets reach the stomach.

5. If gastrointestinal upset is experienced, aspirin can be taken with food or after meals. A readily soluble aspirin preparation should be used and a full glass of water should be taken with the aspirin. Also, an antacid may be taken or a buffered or enteric-coated product may be used.

6. Aspirin use may result in a false-positive reading for glycosuria. 7

. Tinnitus and vertigo may occur with high doses or continued use of aspirin. Reducing the dose will reverse these side effects.

8. Aspirin should be stored in closed, child resistant containers and kept out of the reach of children.

9. Overdoses with aspirin or acetaminophen must be treated promptly.

KEY NURSING IMPLICATIONS

Opioid Analgesics

1. Be proactive with pain control. Offer pain medication on a routine schedule when, in the nurse’s judgment, it is warranted.

2. Drug addiction does not occur frequently when opioids are used therapeutically.

3. Withdrawal symptoms can be prevented or treated by withdrawing the opioid slowly or by using methadone.

4. Assess all clients receiving opioids for respiratory depression. Do not administer opioid analgesics to clients with 12 or fewer respirations per minute. Notify the prescriber of respiratory depression.

5. Respiratory depression can be treated by the use of intravenous naloxone and other measures to support respiration.

6. Observe clients receiving opioids for hypotension, nausea, vomiting, and constipation.

7. To avoid constipation in clients receiving opioid analgesics, increase the client’s intake of fluid and dietary fiber, unless such measures are contraindicated by the client’s treatment plan.

 

KEY NURSING IMPLICATIONS

Opioid Drugs and the Law

1. All opioids are kept under double locks.

2. The use of all opioid drugs must be recorded on a special record and on the client’s record.

3. Lost or contaminated doses must be signed for by two nurses.

4. Opioids are counted by two nurses, one from the oncoming shift and one from the departing shift. Both nurses sign the record.

5. The nurse must be aware of the hospital policy for stop time on opioid orders.

 

NONSTEROIDAL ANTI-INFLAMMATORY DRUGS (NSAIDs)

The nonsteroidal anti-inflammatory drugs (NSAIDs) have emerged as the most important class of drugs used in the treatment of rheumatoid arthritis and related inflammatory disorders. These agents all exhibit varying degrees of analgesic and antipyretic effects and are believed to exert their anti-inflammatory effects by inhibiting the synthesis of prostaglandins. NSAIDs may be classified as salicylates or non-salicylates.

Note: Administration of these products with food, milk, or antacids will reduce the likelihood of gastrointestinal upset. Obtain history of allergic response to drugs. Assess client response to treatment. Keep these and other drugs away from children.

KEY NURSING IMPLICATIONS

Clients Receiving Nonsteroidal Anti-Inflammatory Agents

1. Acetaminophen cannot be substituted for aspirin in clients taking aspirin for its anti-inflammatory effects.

 2. Ibuprofen, ketoprofen, calcium, and naproxen are not recommended for clients allergic to aspirin, those with hemophilia, or those taking anticoagulants.

3. Observe clients taking aspirin for allergic reactions, edema, excessive weight gain, constipation, gastrointestinal upset, tinnitus, and bleeding.

4. Indomethacin is ulcerogenic and can aggravate epilepsy and psychiatric disturbances. Clients allergic to aspirin should not take indomethacin.

5. Use of phenylbutazone may be associated with serious blood abnormalities. Report all evidence of sore throat, bleeding, mouth ulcers, or tarry stools immediately.

KEY NURSING IMPLICATIONS

Clients Receiving Corticosteroids

1. Systemic administration is associated with a broad range of side effects, including gastric ulceration, suppression of the hypothalamic-pituitary-adrenal system, hypertension, and changes in location of body fat deposits.

2. Clients receiving corticosteroids should be monitored for gastrointestinal bleeding and weight gain.

3. Both diabetics and nondiabetics should be monitored for blood glucose elevations while using corticosteroids.

 4. Clients receiving intra-articular injections of these drugs must be cautioned not to overly stress the joint(s).

5. Teach clients on long-term therapy to carry identification and information about their treatment, to continue treatment, not to share medication, and to contact the physician whenever they are under unusual stress.

6. Impending adrenal crisis is indicated by hypotension, restlessness, weakness, lethargy, headache, dehydration, nausea, vomiting, and/or diarrhea.

7. Dietary modifications are specified, including sodium restriction and encouraging intake of calcium, because of a high risk for osteoporosis. Potassium supplementation may be indicated for clients taking corticosteroids.

8. Protect the client from infection and trauma and teach them measures to decrease risk.

9. Administer corticosteroids early in the day to avoid insomnia.

10. Provide instruction and support for the client being withdrawn from corticosteroids.

Self check 1.4

1. Explain common drug use as CNS stimulant and depression
2. Explain nursing responsibilities when administering CNS stimulant or depression