1. What does anterograde amnesia mean and which drugs can cause this effect?

Benzodiazepines can interfere with memory function, an example of when this can occur is in anterograde amnesia. Anterograde amnesia is a subset of amnesia and is the inability to remember events that have occurred while an individual has a certain drug present in their bloodstream. This can happen if for example you are taking benzodiazepines while studying, all the information you process while the drugs mechanism of action is being performed is information that you won’t be able to recall later. 

Benzodiazepines that cause this effect are Midazolam, Flunitrazepam, Lorazepam, Temazepam, Nitrazepam, Triazolam, Clonazepam, Alprazolam, Diazepam and Nimetazepam. 

2. Name the effects of the sedative-hypnotic drugs on the normal sleep pattern and explain their significance to the patient.

• Long term use of benzodiazepines can decrease the amount of time it takes a patient to fall asleep (so the onset of sleep begins faster) and they also increase the total sleep duration (this is only effective in patients which sleep for less than 6hrs per night, so it can help them get the required 8hrs). These two characteristics are why benzodiazepines are effective in the treatment of insomnia. 
• Low doses of benzodiazepines have a small suppressing effect on REM sleep while higher doses cause a bigger suppression. Withdrawal of benzodiazepines often leads to increased periods of REM sleep. 

Benzodiazepines increase the duration of phase 2 NREM (so the body is in a state of deep relaxation for longer) and they decrease the duration of phase 4 NREM. 

3. Which of the sedative-hypnotic drugs are used as a supplementary therapy in anesthesia? Can you explain why?

Both the 1^stgeneration anxiolytic sedative-hypnotic drugs (Barbiturates) and the 2^ndgeneration anxiolytic sedative-hypnotic drugs (Benzodiazepines) are used as supplementary treatments in anesthesia. 

Thiopental (Barbiturate) is ultra short acting and is used in anesthesia. 

Benzodiazepines such as Midazolam, Diazepam and Lorazepam can be used in combination with Barbiturates in anesthesia. These benzodiazepines are the same ones that cause anterograde amnesia and that is why they are drugs of choice because patients don’t recall their procedure (which may be traumatic) when the drugs are in their system. 

4. Which of the sedative-hypnotic drugs are used as anticonvulsants?

Many of the Benzodiazepines as well as the Barbiturates can be used as anticonvulsants. This rests on the fact that both groups of drugs cause potentiation of GABA’s effects and one of GABA’s effects is that it has anticonvulsant properties. 

Thus, Barbiturates such as Phenobarbitone can be used in the treatment of epilepsy. 

Benzodiazepines which have anticonvulsant effects and are used in the treatment of status epilepticus include Lorazepam, Diazepam, Clonazepam and Midazolam. 

5. What is the mechanism of the muscle-relaxing effects of some of the carbamates and the BDs?

Both carbamates and benzodiazepines cause potentiation of GABA’s effects and one of GABA’s effects is that it is a skeletal muscle relaxant. They inhibit polysynaptic reflexes which then result in the relaxing effects. 

6. Discuss the effects of the sedative-hypnotic drugs on the respiratory and cardiovascular systems.

• Benzodiazepines can cause medullar depression. The medulla is the area of the brain containing the Reflex Control Centre as well as the Vital (VMC + Breathing) Centre. If patients are suffering from an underlying pulmonary disease or a cardiovascular disease, then it means that Benzodiazepines can cause even further depression even when given at therapeutic levels. This will mean that they will further worsen the effects already experienced by the patients. 
• The ‘ceiling effect’ further describes the effects of the sedative-hypnotic drugs (Barbiturates & Benzodiazepines) on the respiratory system. 

As the dosage of barbiturates increases (rising above the therapeutic level) it causes maximum respiratory depression which leads to total suppression of the brains vital functions and which then leads to death. This is one of the reasons why they are deemed unsafe. 

As the dosage of benzodiazepines increases (rising above the therapeutic level) it reaches a plateau just below the maximum total respiratory depression (even if the dosage is increased further). This is one of the reasons why benzodiazepines (when used alone) are considered as a safer than Barbiturates. This is because the most harm benzodiazepines will do is cause a coma/anaesthesia in relation to barbiturates that will cause death.