Pharmacology Flashcards
Antipsychotic with best evidence for use in schizophrenia with substance misuse
Clozapine
Best antidepressant for a breastfeeding mother
Sertraline
ADTs with least sexual side effects
Bupropion, Agomelatine, Mirtazapine, Trintellix, Vilazodone. (Mnemonic: BAM TV)
CANMAT 2009 guidelines for continuing ADTs
6-9 months after symptomatic remission or 2 years or more for those with risk factors for recurrence
Cardiac defect in infants associated with lithium
Ebstein’s anomaly
Increase lithium levels
Thiazide diuretics
Low sodium diet
Ibuprofen
ADTs to reduce in renal impairment
Venlafaxine
Paroxetine
Mirtazepine
Bupropion
Valproate is associated with pancreatitis T/F
T
What does caffeine do to lithium levels
Reduces them bcs of diuresis
Investigations before starting lithium
- Renal
- TFTs
- ECG if > 50
Lithium range:
1) acute
2) maintenance
3) toxic
1) 1-1.5 mEq/L
2) 0.2-0.6 mEq/L
3) >2
ADT for breastfeeding
SSRIs & SNRIs - sertraline, fluvoxamine, paroxetine
Most acidic drugs (eg valproate) bind to what? And what do basic (eg phenothiazines, TCAs) bind to?
Acidic- Albumin
Basic- globulin
What are the two phases of drug metabolism?
Phase I (oxidation) - most psych meds, CYP450
Phase II (glucoronidation, sulfation, acetylation, methylation) - Benzos, paliperidone, desvenlafaxine
What’s the most important CYP450 enzyme
CYP3A4 metabolises 50% of drugs & accounts for 50% of cytochrome P450 enzyme in liver
Genetic polymorphism is most common in which CYP450 enzyme?
CYP2D6
7% Caucasians are slow metabolisers
ADTs with minimal effects on weight
Venlafaxine Fluvoxamine Sertraline Trazodone Moclobemide Fluoxetine Desvenlafaxine Bupropion
ADTs that cause weight gain
Paroxetine
Mirtazepine
Doxepin
Amitriptyline
ADTs cause weight gain on the whole yes or no
Yes > 5% increase in weight on average
Peripheral anticholinergic side effects
- Decreased salivation
- Decreased bronchial secretions
- Decreased sweating
- Increased pupil size - (photophobia, precipitation of acute narrow angle glaucoma)
- Inhibition of accommodation - blurred vision
- Increased heart rate (MI)
- Difficulty urinating (AUR)
- Decreased GI motility (constipation)
- Flushed skin
- Hot
Central anticholinergic side effects
- Impaired concentration
- Confusion
- Attention deficit
- Memory impairment
Highly anticholinergic psychotropics
All >15pmol/mL
Atropine
Amitriptyline
Clozapine
Doxepin
Thioridazine
Tolterodine
SSRIs do what to P450
Inhibit
Normal QTc in men and women
M <430msec
W <450msec
Being female is a RF for QTc prolongation T/F
T
Being old is a RF for QTc prolongation T/F
T
ADTs with the highest risk of QTc prolongation
Tricyclics
Also citalopram >40mg
Citalopram in cardiac disease?
Avoid if poss- QTc prolongation
Get a cardiology consult if there are risk factors
Get an ECG before starting citalopram if there aren’t risk factors
Benzos are mainly metabolised where
Liver
Renally excreted- reduce dose in renal impairment
Paliperidone Pregabalin & Gabapentin Risperidone Topiramate Venlafaxine Vortioxetine (not rec in renal failure) Z hypnotics
Lithium excreted where?
Kidney
Psychotropic drugs with Health Canada warnings in liver disease (2)
- Valproic acid
2. Duloxetine
Excretion of gabapentin
Renal
Fine in liver disease
Is serotonin associated with bleeding
Yes, released by plts to promote aggregation
SSRIs inhibit 5HT transporter & cause 5HT depletion in platelets- reduces aggregation
Classic triad of serotonin syndrome
- Excitation (clonus, hyperreflexia)
- Autonomic NS excitation
- Altered mental state
nb can lead to hyperthermia, rhabdomyolysis, DIC, acute resp distress
Rapid onset (cf NMS which is days)
Clinical features of NMS
Hypersalivation
Diaphoresis
Pallor
Stupor
Mutism
Coma
Lead pipe rigidity
Bradyreflexia
Slower onset over days
Clonus with agitation or diaphoresis in a patient on ADTs- what’s going on?
Serotonin syndrome
Management of serotonin syndrome
- Stop offending drug
- Hydrate & monitor closely
- Consider cyproheptadine in moderate to severe cases
- Benzos for sedation if severe
Usually resolves within one week
The signs that characterise NMS
- Fever
- Autonomic instability
- Rigidity
- Tremor
- Elevated CK
- Leukocytosis
- Mental status change
Management of NMS
- Supportive
- Dantrolene 1-2.5 mg/kg iv then 1mg/kg q6h
- Bromocriptine (dopamine agonist)
- Benzos
- ECT
Usually resolves in 1-2 weeks
Contraindications to disulfiram
- Severe CAD, MI, cerebral thrombosis
- DM
- Alcohol use
- Metronidazole
How does clozapine cause sialorrhea?
Via agonism at M4
The neurotransmitter most often associated with alcohol & benzo a) intake and b) withdrawal
a) GABA b) Glutamate
Affect of lithium on psoriasis
Worsens it