Pharmacology Flashcards
The combination of haloperidol with _____ can cause an encephalopathic syndrome mimicking neuroleptic malignant syndrome (NMS) in some patients.
Lithium
Diazepam is metabolized by what CYP450 enzyme? What agents are inhibitors/inducers of the enzyme that you should be mindful if co-prescribed.
CYP3A4. Strong inhibitors of CYP3A4 include the “-azole” antifungals and many antiretrovirals. Strong inducers include antiepileptics, barbiturate’s, and rifampin.
Mechanism(s) of action of Lithium
1) Interferes with sodium, potassium, and calcium channel function.
2) Inhibits inositol monophosphatase, modulating 2nd messenger system changes
What is a target lithium level?
0.8 (average dose of 1500 mg/day)
Organized by the levels at which they present, what are the signs of lithium toxicity?
1.2: Tremors, nausea, diarrhea, ataxia, cognitive slowing, drowsiness
1.5-2: Seizures
>2: Acute renal failure (requires dialysis)
>2.5: Coma, death
What are mild, but common, side effects of Lithium?
Sedation, cognitive difficulties, tremor, increased appetite, weight gain, polydipsia, polyuria, diarrhea, nausea, acne, dry mouth
Of the benzodiazepines FDA approved for sleep onset and sleep maintenance, which two agents have the highest half lives (up to 100 hrs) and have the highest risk of daytime sedation.
Flurazepam and Quazepam
What are the hypnotic agents that are ONLY indicated for sleep ONSET (not sleep maintenance)?
Triazolam, Zolpidem, Zaleplon (Sonata), and Ramelteon
T/F: Women with schizophrenia are more susceptible to side effects from atypical antipsychotics?
True!
What are the two medications used to treat moderate-to-severe psychosis associated with Parkinson’s Disease OR NCD due to LBD?
1) Pimavanserin (Nuplazid) - FDA indication for hallucinations AND delusions in Parkinson’s. Works as a combination of inverse agonist and antagonist activity at the serotonin 2A receptors (5-HT2A)
2) LOW DOSE CLOZAPINE (NOT risperidone)
Mechanism of action of Acamprosate? Contraindication?
Analog of GABA, acts on calcium channels and modifies transmission along GABA and glutamine pathways resulting in decreased positive reinforcement from alcohol intake and decreased withdrawal cravings. Contraindicated if GFR below 30.
What are the only indicated medications for treatment of nocturnal enuresis in children?
Imipramine and desmopressin
Serotonin receptors implicated in atypical antipsychotic weight gain? Timeline of weight gain? Options for adjunctive agents to mitigate weight gain?
1) 5-HT2A and 5-HT2C
2) Early in treatment course - esp first 6 months - then plateaus
3) Aripiprazole, metformin, liraglutide, topiramate
What TCA is the most likely to cause parkinsonian symptoms?
Amoxapine. This is because its metabolites have dopamine blocking activity. It can also cause akathesia or dyskinesia.
Why should TCAs be stopped before elective surgery?
Risk of hypertension when TCAs are given concomitant with anesthetics
What are the only two pharmacologic agents that act as agonists at the GABA-B receptor? What are their indications?
1) Sodium oxybate (gamma-hydroxybutyrate; Xyrem, “date rape” drug); FDA approved for narcolepsy and cataplexy
2) Lioresal (a POTENT antispasticity agent)
What is the name given to the group benzodiazepines that are directly metabolized by glucuronidation and therefore have NO ACTIVE metabolites? What are the specific benzodiazepines?
1) 3-hydroxy benzodiazepines
2) Lorazepam, oxazepam, temazepam (L-O-T)
Why do the 2-keto benzodiazepines have such long half-lives (some of the LONGEST)? What are some specific agents?
1) They have multiple active metabolites that can keep working in the body from 30 to 200 hours (in patients who are slow metabolizers)
2) Chlordiazepoxide, diazepam, prazepam
What is the TCA that is the most serotonergic AND has the highest seizure risk?
Clomipramine (Used in OCD)
What is the most noradrenergic TCA?
Desipramine
What is the therapeutic plasma range for TCAs?
50-150 ng/mL
What is the gap between stopping an MAO-I and starting another anti-depressant? What is the exception?
2 week gap / 5 weeks for fluoxetine
Aside from food restrictions and avoiding SSRIs/clomipramine, what are serious drug-drug interactions to avoid with MAOIs?
Meperidine, anesthetics (lidocaine is OK), asthma medication or OTC drugs containing dextromethorphan, sympathomimetics (epinephrine, amphetamines, cocaine).
What drugs will increase clozapine levels (5)?
Cimetidine, SSRIs, TCAs, valproic acid, erythromycin
What drugs will decrease clozapine levels (2)?
Phenytoin, carbamazepine
Therapeutic range for valproic acid
50 – 100 ng/mL / At 125 ng/ML side effects may occur (including thrombocytopenia)