A1,
A2,
B,
C1,
C2,
D,
E,
F,
G-H,
I-K,
L,
M,
N,
O,
P1,
P2,
Q-R,
S,
T,
U-V,
W-Z
Catapres Side Effects, and Drug Interactions - Clonidine
Catapres Side Effects, and Drug Interactions - Clonidine
SIDE EFFECTS
Tablet
Most adverse effects are mild and tend to diminish with continued
therapy. The most frequent (which appear to be dose-related) are
dry mouth, occurring in
about 40 to 100 patients; drowsiness,
about 33 in 100; dizziness,
about 16 in 100; constipation
and sedation, each
about 10 in 100.
The following less frequent adverse experiences have also been
reported in patients receiving clonidine hydrochloride, but in many
cases patients were receiving concomitant
medication and a
causal relationship has not been established.
- Gastrointestinal: Nausea and vomiting,
about 5 in 100 patients; anorexia and malaise,
each about 1 in 100; mild transient
abnormalities in liver
function tests, about
1 in 100; rare reports of hepatitis; parotitis, rarely.
- Metabolic: Weight gain, about 1 in 100 patients;
gynecomastia, about 1 in 1000; transient
elevation of blood
glucose or serum
creatine phosphokinase, rarely.
- Central Nervous System: Nervousness and agitation,
about 3 in 100 patients; mental
depression, about
1 in 100; headache,
about 1 in 100; insomnia, about 5 in 1000. Vivid dreams or nightmares,
other behavioral changes, restlessness, anxiety,
visual and auditory
hallucinations and delirium have been reported.
- Cardiovascular: Orthostatic symptoms, about 3 in
100 patients; palpitations and tachycardia,
and bradycardia,
each about 5 in 1000. Raynaud's phenomenon, congestive heart
failure, and electrocardiographic abnormalities i.e., conduction
disturbances and arrhythmias have been reported rarely. Rare cases
of sinus bradycardia
and atrioventricular
block have been reported,
both with and without the use of concomitant
digitalis.
- Dermatological: Rash, about 1 in 100 patients;
pruritus, about 7
in 1000; hives, angioneurotic
edema and urticaria,
about 5 in 1000; alopecia, about 2 in 1000.
- Genitourinary: Decreased sexual
activity, impotence
and loss of libido,
about 3 in 100 patients; nocturia,
about 1 in 100; difficulty in micturition,
about 2 in 1000; urinary
retention, about
1 in 1000.
- Other: Weakness, about 10 in 100 patients; fatigue,
about 4 in 100; discontinuation syndrome,
about 1 in 100; muscle
or joint pain,
about 6 in 1000 and cramps of the lower limbs, about 3 in 1000.
Dryness, burning of the eyes, blurred vision, dryness of the nasal
mucosa, pallor,
weakly positive Coombs' test, increased sensitivity
to alcohol and fever
have been reported.
Epidural Injection
Adverse reactions seen during continuous epidural
clonidine infusion are dose
dependent and typical
for a compound of this
pharmacologic class. The adverse events most frequently reported
in the pivotal controlled clinical trial of continuous epidural
clonidine administration
consisted of hypotension, postural hypotension,
decreased heart rate,
rebound hypertension,
dry mouth, nausea, confusion,
dizziness, somnolence,
and fever. Hypotension is the adverse event that most frequently
requires treatment. The hypotension is usually responsive to intravenous
fluids and if necessary,
parenterally-administered ephedrine. Hypotension was observed more
frequently in women and in lower weight patients, but no
dose-related response
was established.
Implantable epidural
catheters are associated with a risk
of catheter-related infections, including meningitis
and/or epidural abscess.
The risk depends on the
clinical situation
and the type of catheter
used, but catheter
related infections occur in 5%-20% of patients, depending on the
kind of catheter used, catheter
placement technique, quality
of catheter care, and
length of catheter
placement.
The inadvertent intrathecal
administration
of clonidine has not been associated with a significantly increased
risk of adverse events,
but there are inadequate safety and efficacy
data to support the
use of intrathecal clonidine.
Epidural clonidine was compared to placebo
in a two-week double-blind study of 85 terminal
cancer patients with
intractable pain
receiving epidural morphine. The adverse events in TABLE 1 were
reported in two or more patients and may be related to administration
of either epidural
clonidine HCl or morphine.
TABLE 1 - Incidence of Adverse Events in the Two-Week
Trial
| Adverse Events |
Clonidine |
Placebo |
| N = 38 |
N = 47 |
| n (%) |
n (%) |
|
Total number
of patients who experienced at least one adverse event.
|
37 (97.4) |
38 (80.5) |
|
Hypotension
|
17 (44.8) |
5 (10.6) |
|
Postural Hypotension
|
12 (31.6) |
0 (0) |
|
Dry Mouth
|
5 (13.2) |
4 (8.5) |
|
Nausea
|
5 (13.2) |
10 (21.3) |
|
Somnolence
|
5 (13.2) |
10 (21.3) |
|
Dizziness
|
5 (13.2) |
2 (4.3) |
|
Confusion
|
5 (13.2) |
5 (10.6) |
|
Vomiting
|
4 (10.5) |
7 (14.9) |
|
Nausea/ Vomiting
|
3 (7.9) |
1 (2.1) |
|
Sweating
|
2 (5.3) |
0 (0) |
|
Chest Pain
|
2 (5.3) |
0 (0) |
|
Hallucination
|
2 (5.3) |
1 (2.1) |
|
Tinnitus
|
2 (5.3) |
0 (0) |
|
Constipation
|
1 (2.6) |
2 (4.3) |
|
Tachycardia
|
1 (2.6) |
2 (4.3) |
|
Hypoventilation
|
1 (2.6) |
2 (4.3) |
An open label
long-term extension
of the trial was performed. Thirty-two subjects received epidural
clonidine and morphine
for up to 94 weeks with a median
dosing period of 10 weeks.
The following adverse events (and percent incidence) were reported:
hypotension/postural hypotension
(47%); nausea (13%); anxiety/confusion (38%); somnolence
(25%); urinary tract
infection (22%); constipation,
dyspnea, fever,
infection (6% each);
asthenia, hyperaesthesia,
pain, skin ulcer,
and vomiting (5% each).
Eighteen percent of
subjects discontinued this study as a result of catheter-related
problems (infections, accidental dislodging, etc.), and one subject
developed meningitis,
possibly as a result of a catheter-related infection. In
this study, rebound
hypertension was not assessed, and ECG
and laboratory data
were not systemically sought.
The following adverse reactions have also been reported with the
use of any dosage form
of clonidine. In many cases
patients were receiving concomitant medication
and a causal relationship has not been established:
- Body as a Whole: Weakness, 10%; fatigue,
4%; headache and withdrawl
syndrome, each 1%. Also reported were pallor,
a weakly positive Coomb's
test, and increased sensitivity
to alcohol.
- Cardiovascular: Palpitations and tachycardia,
and bradycardia, each 0.5%. Syncope, Raynaud's phenomenon, congestive
heart failure, and electrocardiographic
abnormalities (i.e., sinus
node arrest, functional
bradycardia, high degree
AV block) have been reported rarely. Rare case of sinus
bradycardia and
atrioventricular
block have been reported,
both with and without the use of concomitant
digitalis.
- Central Nervous System: Nervousness and agitation,
3%; mental depression, 1%; insomnia,
0.5%. Cerebrovascular accidents, other behavioral changes, vivid
dreams or nightmares, restlessness, and delirium
have been reported rarely.
- Dermatological: Rash, 1%; pruritus,
0.7%; hives, angioneurotic
edema and urticaria,
0.5%; alopecia, 0.2%.
- Gastrointestinal: Anorexia and malaise,
each 1%; mild transient abnormalities in liver
function tests, 1%;
hepatitis, parotitis,
ileus and pseudoobstruction, and abdominal
pain, rarely.
- Genitourinary: Decreased sexual
activity, impotence,
and libido, 3%; nocturia,
about 1%; difficulty in maicturition, about 0.2%; urinary retention,
about 0.1%.
- Hematologic: Theombocytopenia, rarely.
- Metabolic: Weight gain, 0.1%; gynecomastia,
1%; transient elevation
of glucose or serum
phosphatase, rarely.
- Musculoskeletal: Muscle or joint
pain, about 0.6%; leg
cramps, 0.3%.
- Oro-otolaryngeal: Dryness of the nasal
mucosa was rarely reported.
- Ophthalmological: Dryness of the eyes, burning
of the eyes and blurred vision
were rarely reported.
DRUG INTERACTIONS
Tablet
If a patient receiving
clonidine hydrochloride
is also taking tricyclic antidepressants, the effect
of clonidine may be reduced, thus necessitating an increase in dosage.
Clonidine hydrochloride
may enhance the CNS-depressive effects of alcohol,
barbiturates or
other sedatives. Amitriptyline in combination with clonidine enhances
the manifestation
of corneal lesions in rats (See DOSAGE
AND ADMINISTRATION - Tablet: Toxicology.)
Epidural Injection
Clonidine may potentiate
the CNS-depressive effect
of alcohol, barbiturates
or other sedating drugs. Narcotic analgesics may potentiate
the hypotensive effects of clonidine. Tricyclic antidepressants
may antagonize the hypotensive effects of clonidine. The effects
of tricyclic antidepressants on clonidine's analgesic actions are
not known.
Beta blockers may exacerbate the hypertensive
response seen with
clonidine withdrawl. Also, due to the potential
for additive effects
such as bradycardia and
AV block, caution is warranted in patients receiving clonidine with
agents known to affect
sinus node
function or AV nodal
conduction (e.g.,
digitalis, calcium channel
blockers, and beta-blockers.)
There is one reported case
of a patient with acute
delirium associated
with the simultaneous use of fluphenazine and oral
clonidine. Symptoms resolved when clonidine was withdrawn and recurred
when the patient was
rechallenged with clonidine.
Epidural clonidine may prolong the duration
of pharmacologic effects of epidural
local anesthetics, including
both sensory and motor
blockade.
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