Lecture 42 Flashcards
Direct Acting Agonists
1
Q
Dobutamine
A
- Beta 1 Selective agonist
- Increases contractility and chronotropic (HR) effects): increases CO
- Systolic BP in elevated
- Diastolic BP and mean arterial pressure are unchanged
- NO effects on dopamine receptors
- Given IV, half life = 2 minutes
2
Q
Dobutamine Uses
A
- Short term IV inotropic treatment in those with decompensated CHF and following heart surgery
* *Only use for 48-72 hours due to desensitization with prolonged use**
3
Q
Dobutamine Contraindications/Adverse Effects
A
Contraindication: Hypertrophic subaortic stenosis
Adverse Effects: Angina, palpitations, N/V, hypertension
4
Q
Short Acting Beta 2 Agonists
A
- Albuterol (Proventil, Ventolin)
- Terbutaline (Brethaire)
Use to treat breakthrough symptoms and immediate prevention of exercise-induced bronchospasms
5
Q
Long Acting Beta 2 Agonists
A
- Salmeterol (Serevent) - onset 10-20 minutes
- Formoterol (Foradil) - onset 1-3 minutes
- Advair Diskus (Fluticasone/Salmeterol)
Use to treat moderate - severe, persistent asthma when symptoms aren’t controlled by corticosteroids alone
6
Q
Beta 2 Agonists
A
- Differ on selectivity and onset/durations
- Relax/dilate smooth muscle in lungs, uterus, and vasculature of skeletal muscle
- Stabilize mast cells (inhibit histamine and leukotriene release)
7
Q
Beta 2 Agonist Uses
A
- Acute bronchospasm - in those with asthma and COPD
- Bronchospasm prophylaxis - prevention of exercise-induced bronchospasm
- Inhibition of uterine contraction in premature labor (off label)
8
Q
Metaproterenol
A
- Alupent
- Aerosol inhalation
- Onset - 1-30 minutes, peaks at 1 hour, duration 4 hours
- Treats acute bronchospasm in asthma/COPD
9
Q
Terbutaline
A
- Brethaire
- Administered via tablet or SC
- Used to reverse acute bronchospasm in asthma/COPD
- Inhibits uterine contractions for 48-72 hours as well (off label use)
10
Q
Terbutaline WARNING
A
- Do not use in pregnant women to prevent or prolong preterm labor for more than 48-72 hours
- Can cause serious, maternal heart problems and death
11
Q
Albuterol/Levalbuterol
A
- Albuterol = Proventil, Ventolin
- Levalbuterol = Xopenex, R-isomer of Albuterol (s-isomer has no effect)
- Combination: Duoneb or Combivent (Albuterol + Ipratropium)
12
Q
Albuterol
A
- Inhalation, tablets, solution
- Used to treat acute bronchospasms in asthma
- Also in breakthrough symptoms in asthmatics
13
Q
Levalbuterol
A
-Prevents bronchospasms in those 6 years old and older with reversible, obstructive airway disease
14
Q
Salmeterol
A
- Serevent
- Duration - 12 hours
- Combination: Advair (Salmeterol + Fluticasone) - maintenance inhaler for COPD/asthma
15
Q
Salmeterol Uses
A
- Maintain/prevent astham with concomitant corticosteroids
- Bronchospasm prophylaxis with COPD
- Prevent exercise-induced bronchospasm
16
Q
Clenbuterol
A
- Vet use only
- B2 agonist
- Increases lean body mass and activates lipases through B-receptors
- Considered doping substance by most athletic organizations
17
Q
Formoterol
A
- Foridil
- Selective B2 agonist
- Quicker onset than Salmeterol with similar duration
- Same uses as Salmeterol
18
Q
Salmeterol and Formoterol
A
- NOT indicated for acute asthma attacks or status asthmaticus
* *Don’t take extra doses, use short acting B2 agonists for acute bronchospasms** - NOT substitute for corticosteroids
- “Step Down Therapy” - D/C by reducing the dose by 25-50% every 3 months to the lowest dose possible
19
Q
LABA Black Box
A
- Increase the risk of asthma-related deaths
- Increase risk of asthma-related hospitalization
- Use with concomitant use of long-term asthma control medications (inhaled corticosteroids)
- Don’t use if controlled with corticosteroids
- Pediatric/adolescents who need this drug, preferably prescribe combination with corticosteroid to increase adherence of both
20
Q
Beta 2 Agonist Contraindications
A
- *Possible Beta 1 effects**
- Harmful scale: IV > IM = SC > Oral > Inhalation
1. Hypertension, cardiac arrhythmias, cardiac disease due to possible beta 1 activation
2. Hyperthyroidism - increases number of beta receptors in heart, dose related B1
3. Diabetes Mellitus - Beta agonists increase blood glucose
21
Q
Selective Beta 3 Agonist
A
- Mirabegron (Myrbetriq)
- Bladder relaxation of detrusor muscle
- Increases bladder capacity
- At usual doses: selective for B3
- Adverse reaction: hypertension in 9-11%
- Combine with antimuscarinic drug if symptoms persist
22
Q
Seletive Alpha-1 Agonist
A
- Vasoconstrictors
- Direct or indirect sympathetic effects
- Used as decongestants and to increase BP
23
Q
Phenylephrine
A
- Neosynephrine
- Similar to epinephrine structurally
- Alpha 1 agonist, potent vasoconstrictor
- Tablet, liquid, sprays
- Mainly used in combination with antihistamine, dextromethorphan, or APAP
- Metabolized by MAO in liver/intestine
- Used for nasal congestion from cold and allergies
Recent studies found that, when taken orally, doses as high as 40 mg were no more beneficial than a placebo
24
Q
Midodrine
A
- Proamatine
- Alpha 1 agonist
- Oral
- Used for severe postural hypotension (titrate)
- Avoid near bedtime, can cause supine hypertension
- Contraindication: heart disease, renal disease, urinary retention
- Black box: increased supine BP
- *Use in those who can’t tolerate fludrocortisone or to treat intermittent symptoms if non-drug measures fail (water and sodium)**
25
Q
Alpha 1 Agonist Contraindications
A
- Severe cardiac disease and arrhythmias
- During labor
- Hypertension
- Hyperthyroidism, especially if they have an indirect action that could release NE onto the heart
26
Q
Selective Alpha 2 Agonists
A
- Anti-hypertensive effect - CNS activation on locus ceruleus/nucleus tractus solitarius
- Central in origin: can’t cross BBB, can’t lower BP
- Suppresses sympathetic NS activity, PNS predominates
- Useful to treat anxiety, insomnia, pain, and opioid withdrawal (Clonidine patients ideally have all of this)
- Rebound: rapid withdrawal can produce nervousness and anxiety and increase the BP
27
Q
Clonidine
A
- Catapres
- Epidural, oral, patch
- Side effect = sedation
28
Q
Clonidine Uses
A
- Treat hypertension
- Withdrawal from opioids, ethanol, and nicotine side effects: decrease sympathetic outflow
- Treatment of severe pain in cancer patients; epidural produces analgesia (Duraclon - injection)
- Treat ADHD, especially in those with sleep disturbances
- Treat symptoms of anxiety if mainly SNS in nature
29
Q
Clonidine ADHD Treatment
A
- Clonidine ER (Kapvay) and Guanfacine (Intuniv)
- Good alternatives for kids who can’t tolerate stimulants
- May be added on to stimulant therapy as well
- FDA approved to be monotherapy or add-on
- Withdrawal symptom: rebound hypertension
30
Q
Guanfacine
A
- Intuniv
- More selective than Clonidine for alpha-2
- Less frequency and severe rebound
- Use to treat hypertension (moderate to severe)
31
Q
Guanabenz
A
- Wytensin
- Treats moderate to severe hypertension
32
Q
Dexmedetomidine
A
- Precedex
- Alpha 2 agonist
- May produce sedation and decrease anxiety
- Half life 2.5 hours, used for 2-30 days and no incidence of rebound tachycardia/hypertension reported upon withdrawal (unlike clonidine)
33
Q
Precedex Uses
A
- Sedation of intubated and ventilated ICU patients
- Sedation of non-intubated patients prior and during surgical procedures
* *Inhibits SNS and allows less opioids to be needed, doesn’t produce respiratory depression**
34
Q
Methyldopa
A
- Aldomet
- Oral and parenteral
- Therapy for moderate to severe hypertension
- Converted to alpha-methylNE
- Stimulates CNS alpha-2 receptors
- BOX WARNING - When used to HCT, not for initial hypertension therapy, need to titrate patients specifically
35
Q
Brimonidine
A
- Alphagan
- Ophthalmic solution
- Treats increased IOP in open angle glaucoma or ocular hypertension
- Decreases aqueous humor production and increases outflow via uveoscleral pathway (alpha 2 and prostaglandins open it)
- 1000x more selective for alpha 2 than 1 (1 causes mydriasis which could further increase IOP)
36
Q
Combigan
A
Combination of Brimonidine + Timolol
37
Q
Apraclonidine
A
- Iopidine
- Alpha 2 agonist
- Ophthalmic solution
- Less CV side effects
- Similar uses as brimonidine, shorter duration
38
Q
Tizanidine
A
- Zanaflex
- alpha 2 agonist
- Decreases spasticity causes by MS or spinal injury
- Corticospinal motor neurons transmit via glutamate in motor neurons of spinal cord, presynaptic alpha-2 receptors on these neurons inhibit the glutamate release
39
Q
Tramadol
A
- Ultram
- Oral analgesic
- Affinity for mu receptor: 30%, blocks NE receptors: 70%
- Increases NE in synapse which activates alpha 2 presynaptic receptors
- Inhibits calcium uptake into the neuron and decreases glutamate release, decreases transmission of pain pathway
40
Q
Tramadol Contraindications
A
- Abrupt D/C - rebound hypertension, anxiety, nervousness
- Don’t use in those with heart or stroke disease, hypotensive effects may decrease perfusion and worsen ischemic conditions
41
Q
Tramadol Adverse Effects
A
- Sedation
- Headache
- Fatigue
- Confusion
- N/V
- Ejaculation dysfunction
- Hypotension
