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

Anterograde amnesia is when a patient is not able to remember things that have happened while a specific drug is in their system. Therefore, it is memory loss during the drugs action.

Drugs which can cause this effect are benzodiazepines such as midazolam, flunitrazepam, lorazepam, temazepam, etc. 

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

These drugs decrease the time that it takes for the patient to fall asleep, and increases the amount of sleep duration (if the patient originally only slept for <6 hours). The duration spent in stage 2NREM sleep is increased, but the duration spent in REM is decreased. 

The effects caused by the drug are helpful to the patient to treat insomnia. With a better sleep cycle, the patient will have a better mood and therefore quality of life will increase. 

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

Benzodiazepines such as Diazepam, Lorazapam and Midazolam are used supplementary IV in aneasthesia. These drugs cause anterograde amnesia, and they help the patient to fall asleep. Therefore the patient will recall less about the procedure (laying in theatre, moments before procedure etc.) 

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

Some Barbituates such as Phenobarbital and Metharbital are effective for the treatment of generalised tonic-clonic seizures. 

Many Benzodiazepines such as Clonazepam, Nitrazepam, Lorazepam and Diazepam have anti-convulsant effects. Diazepam and Lorazepam can be used when treating status epilepticus. 

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

The benzodiazepines potentiate the effects of GABA. This leads to inhibition of the post-synaptic potential and consequently causes muscle relaxation.

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

 Sedative-hypnotics are CNS suppressive. The medulla oblongata, which is located in the brain, contains the respiratory and cardiovascular centres. Therefore when these drugs are administered, it suppresses the respiratory and cardiovascular system's function. If these drugs are abused, it can lead to death.