Ch 17

Question 1

centrally acting A2 agonists act as

Answer 1

direct acting adrenergic receptor blocker

Question 2

Clonidine is approved for

Answer 2

HTN
severe pain
ADHD

centrally acting a2 agonist

Question 3

Clonidine and HTN

Answer 3

works on the brainstem -> reduces sympathetic outflow to blood vessels and heart

Question 4

Adverse effects of Clonidine

Answer 4

Drowsiness
xerostomia
rebound HTN
abuse
constipation
impotence
gynecomastia
vivid dreams
nightmares
anxiety
depression

Question 5

Rebound HTN with Clonidine symptoms and why

Answer 5

symptoms
nervousness
tachycardia
sweating

occurs in response to clonidine withdrawal
can be avoided by withdrawing slowly over 2-4 days

Question 6

if blood pressure climbs dangerously high, it should be lowered with a combo of _____ for rebound HTN

Answer 6

combo of A and B adrenergic blocking agents

Question 7

clonidine and pregnancy

Answer 7

no

Question 8

abuse potential of clonidine

Answer 8

euphoria
sedation
hallucinations

also can intensify effects of some abused drugs such as benzodiazepines, cocaine and opioids

Question 9

extended release clonidine for ADHD

Answer 9

Kapvay

Question 10

Pt education for Clonidine

Answer 10

take major portion of daily dose at bedtime to minimize daytime sedation

for transdermal patches - apply to hairless, intact skin on upper arm or torso and apply a new patch every 7 days

Patch contains metal - must be removed for MRI

take and record BP daily - call if hypotension develops

Do not discontinue abruptly - can cause tachycardia and other dysrhythmias. Advise to carry an adequate supply when traveling and a copy of prescription

possible CNS depression- avoid driving or hazardous activities if alertness is reduced.

Dry mouth - chew sugarless gum, sucking on hard sugar free candy, sip fluids

potential for rebound hypertension - refill promptly so dont run out. never discontinue on own

Question 11

centrally acting A2 agonist indicated for HTN and ADHD, similar to Clonidine

Answer 11

Guanfacine
sedation and dry mouth,
rebound HTN with abrupt withdrawal

Question 12

oral antihypertensive that lowers BP by acting at sites within CNS (safe in pregnancy)

Answer 12

Methyldopa

Question 13

Methyldopa severe side effects

Answer 13

hemolytic anemia

hepatic necrosis

Question 14

How is Methyldopa an A2 agonist

Answer 14

methyldopa is taken into the brainstem and converted into methylnorepinephrine - a effective A2 agonist

Question 15

Do you have to worry about orthostatic hypotension with Methyldopa or Clonidine

Answer 15

no

Question 16

Labs for Methyldopa

Answer 16

Combs test
Blood counts (Hgb, HCT, red cell count)
before and periodically thereafter
(CBC)

liver Function Test

Question 17

A positive coombs test

Answer 17

if they do not develop hemolytic anemia, they can continue on Methyldopa

if they develop hemolytic anemia -> withdraw Methyldopa (coombs may remain positive for months)

Question 18

a positive coombs test usually occurs (if its going to occur)

Answer 18

between 6-12 months

Question 19

Methyldopa and hepatotoxicity

Answer 19

associated with hepatitis, jaundice and rarely fatal hepatic necrosis.

Question 20

other adverse effects of Methyldopa

Answer 20

xerostomia
sexual dysfunction
orthostatic hypotension
drowsiness
reduced mental acuity
nightmares
depression

Question 21

children and centrally acting A2 agonist

Answer 21

approved for age 6 and older

Question 22

centrally acting A2 agonist pregnant

Answer 22

no for clonidine

methyldopa yes

Question 23

centrally acting A2 agonist and breastfeeding

Answer 23

no for clonidine

Question 24

older adults and centrally acting A2 agonist

Answer 24

BEERS says no for 65 and older

Question 25

High risk pt for clonidine

Answer 25

pt with bradycardia
dose adjustments for pt who take CNS depressants

not for pregnancy

Question 26

centrally acting A2 agonist high risk

Answer 26

methyldopa should not be given with active liver disease or a history of methyldopa-induced liver function

Question 27

principal mechanism of methyldopa

Answer 27

vasodilation