Also known as hypno-sedative drugs. These drugs are also called minor tranquillizer, anxiolytics or hypnotics or sedative drugs.
Mechanism of action:
- It depresses subcritical (region beneath the cerebral cortex) level of the CNS especially limbic system and reticular formation (emotional brain).
- It also increases the effect of powerful inhibitory neurotransmitter (e.g., GABA) in the brain, which causes calmative effect (decrease GABA cause anxiety).
Indication
Anxiety neurosis
Phobic neurosis
Insomnia
Convulsion
Skeleton muscles spasm
Preoperative sedation.
Classification
A. Barbiturates
B. Benzodiazepines
C. Non-barbiturates, non-benzodiazepines
D. Newer drugs
A. Barbiturates :-
These are salt of barbituric acid. These are used for hypnotic and sedative effects.
Classification – based on duration of action
- long acting barbiturates – duration of action is more than 8 hours, example – phenobarbital (used as anticonvulsant)
- Intermediate acting barbiturates – duration of action between 5-8 hours, example – pentobarbital, amobarbitol.
- Short acting barbiturates – duration of action between 1-5 hours, example – secobarbital.
- Ultra Short acting barbiturates – duration of action less than 1 hour, example – thiopental sodium(used as Short acting anaesthesia).
Side effects of barbiturates :
Dizziness, irritability, confusion, agranulocytosis, megaloblastic anaemia, thrombocytopenia, allergic reaction.
B. Benzodiazepine :-
These drugs act quickly and effectively to reduce anxiety symptoms by increasing the activity of the neurotransmitter GABA in the brain
- Today benzodiazepine groups are drugs of 1st choice in the treatment of anxiety and insomnia.
- 1st benzodiazepine, chlordiazepoxide is discovered by Stern bach in 1957.
- Continuous long time use of benzodiazepines more than 6 weeks produce tolerance or dependence so it should be tapered gradually over 2 to 6 weeks.
- In is contraindicated in client with acute narrow angle glaucoma.
- Flumazenil is used as antagonist of benzodiazepines.
- Classification – based on duration of action.
- Long acting – Duration of action 20-60 hours, example – diazepam, nitrazepam, clonazepam, flurazepam, chlordiazepoxide etc.
- Short acting – Duration of action 5-15 hours, example – alprazolam, oxazepam, lorazepam.
- Very short acting – duration of action 2-5 hours, example – midazolam, triozolam.
Side effects of benzodiazepines :
Day time sedation, headache, hypotension, tachycardia, constipation, urinary retention, blurred vision, alexia, amnesia, lethargy, tremors, behavioural changes, paradoxical CNS stimulation.
Antidote for benzodiazepines:- Flumazenil (Romazicon)
C. Non-barbiturates, non-benzodiazepines anti anxiety drugs :-
Classified in the following categories –
- Quinazoline – These drugs were the “street drug” before discovery of benzodiazepines, example methaqualone.
- Alcohol – Alcohol was used as an anti-anxiety or sedative since long-time. It produces excessive dependence; examples of alcohol use as drinking is ethanol.
- Anti-Histamine – Their use as an anti-anxiety Drive is minimum today, example promethazine (phenergan), diphenhydramine, hydroxyzine.
- Beta blockers – Basically these drugs are anti-hypertensive but today mainly used as anti-anxiety, example propranolol.
D. Newer drugs
Examples are duspirone, zolpidem, zopiclone.
Nursing Management –
- instruct the client not to stop the drug abruptly.
- Avoid alcohol and driving.
- Avoid the work which needs more alertness.
- Monitor visual disturbance, renal function, liver function test.
- Monitor paradoxical CNS stimulation during every therapy.
- Not to take medicine without consulting HCP.
- Instruct client that handover effect may be seen.