Psych - Mood Stabilisers, Benzos, Z drugs, Stimulants and Anti-Dementia Flashcards
Lithium: what is it? Name some important uses
- Mood stabiliser
- Prophylaxis (recurrent affective disorder - unipolar and bipolar)
- Acute treatment of mania
- Augmentation of antidepressants in resistant depression
- Schizoaffective illness
- Control of aggression
What are the mechanisms of action of Lithium? How does lithium leave the body? What is the therapeutic range?
- Lithium interacts anywhere Na, K+ or Mg+
- Therapeutic levels: probably effects neuro-transmission (5HT, noradrenaline, dopamine and acetylcholine)
- Has action on thyroid and kidney (via cAMP receptors)
- Excreted renally - narrow therapeutic range (0.4-1.0mmol/L
What monitoring is required for a patient on lithium?
- TFT and U+E b/f start and then every 6/12
- Serum lithium levels (initially weekly and then every 12/52), bloods taken 12h after last dose
Name some side effects of lithium (within therapeutic window)
- Nausea
- Fine tremor
- Weight gain
- Oedema
- Polydipsia and polyurethaning
- Exacerbation of psoriasis and acne
- hypothyroidism
Name some side effects of lithium toxicity (>1.0mmol/L)
- Vomiting
- Diarrhea
- Coarse tremor
- Slurred speech
- Ataxia
- Drowsiness and confusion
- Convulsions and coma
What is the treatment of lithium toxicity or overdose?
- Cessation of lithium
- Fluid therapy (to restore GFR) and I+O monitoring in order to normalise urine output and enhance lithium clearance
What are some contra-indications of Lithium? Name some drugs which cause ADRs when combined with lithium
- Avoid in renal, cardiac, thyroid and Addison’s disease
- Dehydration and diuretics
- ADRs: NSAIDs, CCBs
Name 3 very teratogenic mood stabilisers/anti-epileptics
- Carbamazepine
- Lithium
- Valproic acid
Name some benzos and give some indications of use
-Clonazepam, chlordiazepoxide, diazepam, lorazepam
Indications
- Alcohol withdrawal
- Muscle relaxant
- Anticonvulsant
- Control of violent behaviour
- Insomnia (short term)
- Generalised anxiety (short term 2-4 weeks) but should not be used for phobias or panic disorder
What is the mechanism of action of benzos?
- Psychoactive drug
- Potientate the inhibitory effects of GABA at GABA A receptors, resulting in sedative, anxiolytics, hypnotic, anticonvulsant and muscle relaxing properties
What are the important pharmacokinetics of benzos?
- Long acting: diazepam, chlordiazepoxide and nitrazepam
- Short acting: lorazepam and tamazepam
- Avoid in pregnancy and elderly patients
What are the side-effects of benzos? What drugs should not be used alongside them?
• Drowsiness and lightheadedness next day
• Ataxia (increased falls risk in older people)
• Amnesia
• Dependence
• Disinhibition (can lead to aggression)
*Benzos potentiate alcohol and other sedatives - dangerous risk of OD
What are the signs of a benzo OD? What is the treatment?
- Signs: respiratory depression, drowsiness, dysarthria and ataxia
- Treatment: flumazenil (selective benzo antagonist) - caution with mixed ODs (eg with TCAs) and should have expert review
What area Z drugs? Give some names, MOA and some side effects
- Zopiclone, Zolpidem, zalepon
- Have similar effect to benzos but are different structurally - act on alpha2 subunit of the GABA receptor to potentiate the inhibitory effects of GABA
- Similar SEs to benzos (agitation, bitter taste in mouth, constipation, decreased muscle tone, dizziness, dry mouth) and have an increased risk of falls in the elderly
- Do not have anticonvulsant or muscle relaxing properties
Name a stimulant used in ADHD and explain its MOA and side effects
- Methylphenidate: inhibits the reuptake of dopamine and noradrenaline, increasing dopaminergic and noradrenergic activity in the pre-frontal cortex (which normally regulates behaviour, attention and emotion). This excitatory effect is thought to compensate for the normally lower levels of excitation in ADHD patients and brings them up to threshold where continual stimulation (to try and raise excitation levels) is no longer required.
- SEs: growth suppression, decreased appetite, weight loss, anxiety, agitation and insomnia
