CH4: CNS DRUGS Flashcards
(28 cards)
What are the long acting benzodiazepines?
CCAD
Chlordiazepoxide
Clobazam
Alprazolam
Diazepam
What are the short acting benzodiazepines?
LO
- Lorazepam
- Oxazepam
Side effects of benzodiazepines?
- Paradoxical effects (opposite effect = due toxicity) e.g. anxious, aggressive, hostility, excited
- Sedative effects
- Increased by use with alcohol, CNS depressants (opioids, other sedatives) and CYP inhibitors.
Name the benzodiazepines that have a driving limit
COLD FT
Clonazepam
Oxazepam
Lorazepam
Diazepam
Flunitrazepam
Temazapam
Antidote for benzodiazepine overdose
Flumazenil
Benzos in pregnancy?
- Use may cause neonatal withdrawal symptoms
- AVOID unless there is a clear indication such as seizure control
What are the dependency symptoms for benzos? & how long this can occur in long term and short term use
anxiety, weight loss, loss of appetite, sweating, tremor and tinnitus
May occur up to 3 weeks for long term use of benzos, up to 1 day for short term use.
How to slowly withdraw benzos?
- Convert all benzos to ONCE a nightly dose of diazepam
- Reduce dose to 1-2mg (1/10th of the larger dose) every 2-4 weeks
> can reduce further if pt has overcome withdrawal symptoms - Reduce further (0.5mg to near end)
What class of drugs should be avoided when using benzos?
- Beta blockers
- Antipsychotics
- Antidepressants (SSRIs, TCA, MAOIs)
Sertraline
- 1st line treatment for treating depression
- Safer for patients with cardiac events
- better tolerated and safe in overdose
Fluoxetine
licensed for ages 5-18 for treating depression
SSRIs side effects
• GI disturbances: diarrhoea, vomiting
• Weight gain/ fluctuations
• Sexual dysfunction
• Risk of bleeding: increased by NSAIDs, anticoagulants… => offer GI protection
• Insomnia- take in morning to avoid this
• QT prolongation (Especially with escitalopram/ citalopram)
• Hyponatraemia
• Suicide ideation
• Serotonin syndrome
• Hypersensitivity – stop if rash occurs
What TCAs are not recommended for treatment of depression
- Amitriptyline
- Dosulepin
They are both dangerous in overdose.
State the sedating TCAs
CATD
Clomipramine
Amitriptyline
Dosulepin
Trazadone
better for agitated and anxious patients – helps with sleep
State the less sedating TCAs
NIL
Nortriptyline
Imipramine (most antimuscarinic)
Lofepramine (hepatotoxic)
Better for withdrawn and apathetic patients
Side effects for TCAs
CASHH
Cardiac event (QTc prolongation)
Antimuscarinic
Seizures
Hypotension
Hallucination
Interactions of SSRIs
• CYP enzyme inhibitors: avoid grapefruit- increases concentration
• CYP enzyme inducers reduces effectiveness
• Drugs that cause QT prolongation: amiodarone, sotalol, quinolones, antipsychotics, macrolides, TCA’s…
• Drugs that increase bleed risk
• Hyponatraemia: carbamazepine and diuretics
• Serotonin syndrome
Interactions of TCAs
• CYP enzyme inhibitors – avoid grapefruit – increases plasma concentrations
• CYP enzyme inducers – reduces effectiveness
• Drugs that cause QT prolongation – amiodarone, sotalol, quinolones
• Anti-muscarinic drugs
• Anti-hypertensive drugs
• Serotonin syndrome
Name the MAOIs drugs that cause hepatotoxicity
phenelzine and isocarboxazid
Side effects of MAOIs
Hypertensive crisis
- STOP if the throbbing headache
- avoid: OTC pseudoephedrine and sympathomimetics and dopaminergic drugs
- avoid: tyramine rich foods, stale foods
The combination therapy of tranylcypromine + clomipramine may cause?
- fatal
- cause hypertensive crisis
Washout period for starting MAOIs after SSRIs have been stopped?
1 week after SSRIs or related antidepressant has been stopped
5 weeks- Fluoxetine
2 weeks - Sertraline
Washout period for starting MAOIs after TCAs have been stopped?
1-2 weeks after TCAs or related antidepressants have been stopped
3 weeks - Clomipramine or Imipramine
Washout period for starting MAOIs after previous use of MAOIs has been stopped?
2 weeks
unless it is Moclobemide = short-acting, no wash out periods required
