BNF for Children 2011-2012

BNFC 2011–2012 4.9.2 Antimuscarinic drugs used in dystonias 2374.9.2 Antimuscarinic drugsused in dystoniasThe antimuscarinic drugs procyclidine and trihexyphenidylreduce the symptoms of dystonias, includingthose induced by antipsychotic drugs; there is no justificationfor giving them routinely in the absence ofdystonic symptoms. Tardive dyskinesia is not improvedby antimuscarinic drugs and may be made worse.There are no important differences between the antimuscarinicdrugs, but some children tolerate one betterthan another.Procyclidine can be given parenterally and is effectiveemergency treatment for acute drug-induced dystonicreactions.Cautions Antimuscarinics should be used with cautionin cardiovascular disease, hypertension, psychotic disorders,pyrexia, and in those susceptible to angle-closureglaucoma. Antimuscarinics should not be withdrawnabruptly in children taking long-term treatment.Antimuscarinics are liable to abuse. Interactions:Appendix 1 (Antimuscarinics).Skilled tasks Antimuscarinics can affect performanceof skilled tasks (e.g. driving).Contra-indications Antimuscarinics should beavoided in gastro-intestinal obstruction and myastheniagravis.Hepatic and renal impairment Procyclidine andtrihexyphenidyl should be used with caution in childrenwith hepatic or renal impairment.Side-effects Side-effects of antimuscarinics includeconstipation, dry mouth, nausea, vomiting, tachycardia,dizziness, confusion, euphoria, hallucinations, impairedmemory, anxiety, restlessness, urinary retention, blurredvision, and rash. Angle-closure glaucoma occurs veryrarely.PROCYCLIDINE HYDROCHLORIDECautions see notes above; interactions: Appendix 1(antimuscarinics)Contra-indications see notes aboveHepatic impairment see notes aboveRenal impairment see notes abovePregnancy use only if potential benefit outweighs riskBreast-feeding no information availableSide-effects see notes aboveLicensed use not licensed for use in childrenIndication and doseDystonias. By mouthChild 7–12 years 1.25 mg 3 times dailyChild 12–18 years 2.5 mg 3 times dailyAcute dystonia. By intramuscular or intravenous injectionChild under 2 years 0.5–2 mg as a single doseChild 2–10 years 2–5 mg as a single doseChild 10–18 years 5–10 mg (occasionally morethan 10 mg)Note Usually effective in 5–10 minutes but may need 30minutes for reliefProcyclidine (Non-proprietary) ATablets, procyclidine hydrochloride 5 mg, net price28-tab pack = £2.77. Counselling, drivingArpicolin c (Rosemont) ASyrup, sugar-free, procyclidine hydrochloride 2.5 mg/5 mL, net price 150 mL = £4.22; 5 mg/5 mL, 150 mLpack = £7.54. Counselling, drivingKemadrin c (Aspen) ATablets, scored, procyclidine hydrochloride 5 mg, netprice 100-tab pack = £4.72. Counselling, drivingKemadrin c (Auden Mckenzie) AInjection, procyclidine hydrochloride 5 mg/mL, netprice 2-mL amp = £1.49TRIHEXYPHENIDYLHYDROCHLORIDE(Benzhexol hydrochloride)Cautions see notes above; interactions: Appendix 1(antimuscarinics)Contra-indications see notes aboveHepatic impairment see notes aboveRenal impairment see notes abovePregnancy use only if potential benefit outweighs riskBreast-feeding avoidSide-effects see notes aboveLicensed use not licensed for use in childrenIndication and doseDystonia. By mouthChild 3 months–18 years initially 1–2 mg daily in1–2 divided doses, increased every 3–7 days by1 mg daily; adjusted according to response andside-effects; max. 2 mg/kg dailyTrihexyphenidyl (Non-proprietary) ATablets, trihexyphenidyl hydrochloride 2 mg, netprice 84-tab pack = £19.60; 5 mg, 84-tab pack =£16.79, 100-tab pack = £15.60. Counselling, before orafter food, drivingBroflex c (Alliance) ASyrup, pink, black currant, trihexyphenidyl hydrochloride5 mg/5 mL, net price 200 mL = £7.44.Counselling, driving4.9.3 Drugs used in essentialtremor, chorea, tics, andrelated disordersHaloperidol can improve motor tics and symptoms ofTourette syndrome and related choreas (see section4.2.1). Other treatments for Tourette syndrome includepimozide (p. 176) [unlicensed indication] (important:ECG monitoring required) and sulpiride (p. 176) [unlicensedindication].Propranolol or another beta-adrenoceptor blockingdrug (section 2.4) may be useful in treating essential4 Central nervous system