Prototype Drug Unit 1 & 2 Exam- Phenobarbital (Luminal)

Question 1

What is the Therapeutic classification of this drug?

Answer 1

Sedative-hypnotic, antiepileptic drug

Question 2

What is the pharmacologic classification of this drug?

Answer 2

Barbiturate, GABA receptor agonist

Question 3

What are the therapeutic effects and uses of this drug?

Answer 3

It is a schedule 4 drug that is available as tablets or elixir for PO doses and as injection for IM or IV administration. It is effective for treating generalized and partial seizures. The drug is FDA approved for the short-term treatment of insomnia. Therapeutic serum phenobarbital concentrations range from 15 to 40 mcg/mL. It decreases time to sleep onset and lengthens total sleep time.

Question 4

What is the mechanism of action for this drug?

Answer 4

It binds to GABA receptors where it enhances the activity of GABA

Question 5

What is the route of this drug?

Answer 5

PO, IM, and IV

Question 6

How is this drug absorbed?

Answer 6

Well absorbed by all routes

Question 7

How is this drug distributed?

Answer 7

Rapidly and widely distributed; may cross the placenta; secreted in breast milk; 20-45% bound to protein

Question 8

Where is it primarily metabolized?

Answer 8

In the liver

Question 9

How is it primarily excreted?

Answer 9

Renal

Question 10

What are the adverse effects of this drug?

Answer 10

Coma, Stevens-Johnson syndrome, angioedema, and thrombophlebitis. Adverse reactions related to CNS depression include oversedation, “hangover” effect, lethargy, and hallucinations.

Question 11

What are the contraindications/precautions of this drug?

Answer 11

Should not be given to patients who have hypersensitivity to barbiturates, suicidal ideation or previous suicide attempt, preexisting CNS depression, severe respiratory disease, severe pain, or hyperthyroidism. Patients with impaired hepatic, renal, and cardiovascular function should not receive this drug. People with COPD should not receive this drug. People who have family history of porphyria should not be given this drug. It can cause birth defects and physical dependence in a neonate and can be excreted through breast milk.

Question 12

What are the drug interactions of Phenobarbital?

Answer 12

Can interact with drugs that are metabolized by the liver such as corticosteroids, oral contraceptives, and anticonvulsants. Use with other CNS depressants, including alcohol, will cause additive sedation. Valproic acid may increase the risk of phenobarbital toxicity. Can decrease the effectiveness of digoxin, TCA’s, mentronidazole, quinidine, or oral anticoagulants.

Question 13

What are the herbal or food interactions of Phenobarbital?

Answer 13

St. John’s Wort may lead to decreased barbiturate effect. Use of kava, chamomile, eucalyptus, lemon balm, or valerian may increase additive CNS depression.

Question 14

What is the pregnancy category of Phenobarbital?

Answer 14

Category D

Question 15

What is the treatment of overdose of Phenobarbital?

Answer 15

Overdosage of phenobarbital is a medical emergency and may be fatal. Activated charcoal is administered followed by gastric lavage. Alkinization of the urine with sodium bicarbonate increases the renal elimination of phenobarbital

Question 16

What are the Nurse Responsibilities with this drug?

Answer 16

1) Assess (get a full history. Check for disturbances in thought processes, preception, verbal communication, affect behavior, interpersonal relationships, and self-care. Get vital signs. Evaluate lab findings. Assess the patient’s ability to receive and understand instructions.)
2) Give Medications
3) Reassess (Check to see if therapeutic effects are working. Continue to monitor vital signs. Monitor motor activity and coordination. Ensure adequate nutrition. Monitor for and immediately report signs and symptoms of NMS: unstable blood pressure, elevated temp, diaphoresis, muscle regidity. Monitor cardiovascular and respiratory function for frequently with elderly people with dementia. Monitor for the possibility of pregnancy in women of childbearing age. Monitor for alcohol and illegal drug use. Monitor caffeine use. Monitor for smoking.)
4) Help patient understand drug therapy, desired therapeutic outcomes, commonly adverse effects, parameters for when to call the health care provider, and any necessary monitoring or precautions.
5) Help Patient understand how to self-administer the drug