Clinical Pharmocology Flashcards
What are examples of benzodiazepines?
- Midazolam
- Diazepam
- Lorazepam
When are benzodiazepines indicated for use?
- Seizure termination
- Severe panic disorders
- Anxiety disorders - short term only
- Insomnia - short term
- Alcohol withdrawal
- Perioperative sedation
When are benzodiazepines contraindicated for use?
- Resp muscle weakness
- Sleep apnoea
- COPD
- Pregnancy
- Breast feeding
How do Benzodiazepines work?
Potentiate GABA neurotransmission
What are edverse drug reactions to benzodiazepines?
Features of Over-sedation
- Drowsiness
- In-coordination
- Muscle weakness
- Dizziness
- Confusion
- Respiratory arrest
What is the half-life of midazolam?
2 hours
What is the half-life of lorazepam?
8 hours
What is the half-liofe of diazepam?
30 hours
What are examples of triptans?
Sumatriptan
when are triptans indicated for use?
Migraines
When are triptans contraindicated?
- IHD
- Coronary Vasospasm
- Previous MI
- Uncontrolled/severe hypertension
How do triptans work?
Triptans are 5-HT1D receptor agonists and therefore block the receptors so 5-HT is unable to bind to the receptor on the vascular endothelium. This is thought to stop 5-HT (serotonin) from stimulating the vascular endothelium to release nitric oxide, causing vasodilation with stimulation of meningeal sensory nerve endings.
What are common side effects of triptans?
- Sensations of tingling, heat, pressure or tightness in any part of the body.
- Dizziness
- Weakness
- Fatigue
- Nausea and vomiting
- Drowsiness
Can also have - dyspepsia, Abdo pain, Tachycardia, myalgia, med-overuse headache
What should you be very careful giving triptans with?
SSRI’s - both together can cause serotonin syndrome
What are indications for using carbemazepine?
- Generalised/focal seizures
- Trigeminal neuralgia
What is the mechanism of action of carbemazepine?
Acts by binding to the sodium channels of neuronal membranes and prevents the influx of sodium into the cell which normally leads to an action potential. By preventing depolarisation of these neurones, there is not the repeated “firing” of action potentials that is responsible for epileptic seizures.