Download Commonly prescribed medication

Benztropine
Addition to the List
Note: Commonly prescribed medication.
Literature question
Is benztropine effective and safe?
Literature search
Medline: Benztropine AND efficacy AND limit to (meta-analysis)
Cochrane: Benztropine AND efficacy
Soares-Weiser K, Mobsy C, and Holliday E. “Anticholinergic medication for neuroleptic-induced tardive
dyskinesia (Review).” The Cochrane Library (2012).
Implications for practice. Based on the currently available data, this systematic review can provide no reliable
conclusions about the use of anticholinergics (benzhexol, benztropine, biperiden, orphenadrine, procyclidine,
scopolamine or trihexylphenidyl) for the treatment of neuroleptic-induced TD. In addition, there is no evidence to
support the suggestion that the withdrawal of these medications may benefit people with TD. In the absence of
evidence one way or another, the clinician must balance the possible benefits against the potential adverse effects of
the treatment.
Katzenschlager R, Sampaio C, Costa J, and Lees A. “Anticholinergics for symptomatic management of
Parkinson’s disease (Review).” The Cochrane Library (2009).
Main results. Trial duration was between five and 20 weeks and drugs investigated were benzhexol (mean doses: 8
to 20 mg/d), orphenadrine (mean dose not reported), benztropine (mean dose not reported), bornaprine (8 to 8.25
mg/d), benapryzine (200 mg/d), and methixine (45 mg/d). Only one study involved two anticholinergic drugs.
Outcome measures varied widely across studies and in many cases, the scales applied were the authors´ own and
were not defined in detail. Incomplete reporting of methodology and results was frequent. The heterogeneous study
designs as well as incomplete reporting precluded combined statistical analysis. Five studies used both tremor and
other parkinsonian features as outcome measures. Outcome measures in these five studies were too different for a
combined analysis and results varied widely, from a significant improvement in tremor only to significant
improvement in other features but not in tremor. All studies except one (dealing with methixine) found a significant
improvement from baseline on the anticholinergic drug in at least one outcome measure. The difference between
placebo and active drug was reported in four studies and was found to be significant in all cases. No study failed to
show superiority of the anticholinergic over placebo. The occurrence of neuropsychiatric and cognitive adverse
events was reported in all but three studies (in 35 patients on active drug versus 13 on placebo). The most frequently
reported reason for drop-outs from studies was in patients on placebo due to withdrawal from pre-trial
anticholinergic treatment.
Powney MJ, Adams CE, and Jones H. “Haloperidol for psychosis-induced aggression or agitation (rapid
tranquillisation) (Review).” The Cochrane Library (2012).
Adverse events In terms of movement disorders and the emergence of ataxia (1 RCT, n = 66, RR 0.44 CI 0.04 to
4.65), dystonia (1 RCT, n = 66, RR 3.54 CI 0.42 to 30.03), speech disorder (1 RCT,n = 66, RR 1.77 CI 0.35 to 9.01),
rigidity (1 RCT, n = 66, RR 6.22 CI 0.33 to 115.91), tremor (1 RCT, n = 66, RR 1.77 CI 0.17 to 18.60) and the need
for benztropine (1 RCT, n = 66, RR 1.99 CI 0.68 to 5.83). One study (n = 60) reported that significantly more
participants experienced EPS in the haloperidol group compared with the lorazepam group (RR 15.00 CI 2.11 to
106.49, Analysis 13.7).
Walshe M, Smith M, and Pennington L. “Interventions for drooling in children with cerebral palsy
(Review).” The Cochrane Library (2012).
Pharmaceutical Interventions. Both studies on pharmaceutical interventions (Camp-Bruno 1989; Mier 2000)
compared intervention versus placebo. They differed in the medications given and outcome measures used. CampBruno 1989 examined reduction in salivary flow and found a statistically significant difference in salivary flow
between participants (age range 4-44 years) on placebo and those taking benztropine (p<.001) immediately after
intervention. Both studies examined the frequency and severity of drooling albeit using different outcome measures.
Camp-Bruno 1989 defined a ’responder’ as those participants who obtained a mean TDS rating of less than 3. They
also defined ’responsivity’ as a decrease of one baseline SD or greater. Mier 2000 defined an improvement of 4
points or greater in their 9 point scale as a standard for significant ’clinical improvement’. On the Teacher Drool
Scale, Camp-Bruno 1989 found a statistically significant difference between both placebo and intervention in the
frequency and severity of drooling immediately after intervention (p_0.001).Mier 2000 using an adaptation of
Thomas-Stonell and Greenberg Scale also found a statistically significant difference between the placebo and
intervention immediately after intervention (p<0.001). It is unknown how long the effects of these medications
lasted in terms of reducing the quantity of saliva produced and reducing the frequency and severity of drooling.
The adverse effects of benztropine reported were behavior changes such as irritability and listlessness. Medical side
effects reported were insomnia, vomiting, dilated pupils, disorientation, facial flushing, ’glassy eyes’ , stomachache,
and dry mouth. Three children of the 27 (11%) children in Camp-Bruno 1989 were excluded because of adverse
reactions to benztropine. Eight of the 39 (20.5%) children inMier 2000 study dropped out because of the adverse
side effects to glycopyrrolate. As with the trials on BoNT-A, it is difficult to determine whether all adverse effects
reported were directly related to the medication.