McKenna's Drug Handbook for Nursing & Midwifery, 7e

59 Muscle relaxants baclofen dantrolene sodium mebeverine hydrochloride orphenadrine (See Chapter 60, ANTIPARKINSONian DRUGS ) ropinirole (See Chapter 60, ANTIPARKINSONian DRUGS )

severity or frequency of muscle spasm or reduced muscle tone should appear within 4–8 hours. If response is inadequate, second test dose of 75mcg/1.5mL is given 24 hours after first. If response is still inadequate, final test dose of 100 mcg/2 mL is given 24 hours later. Individuals unresponsive to 100-mcg dose should not be considered candidates for implantable pump. Maintenance therapy— Initial dose is titrated based on screening dose that elicited an adequate response.This effective dose is doubled and administered over 24 hours. However, if screening dose efficacy was maintained for 12 hours or longer, dose is not doubled. After first 24 hours, dose is increased slowly as needed and tolerated by 10–30% daily. During prolonged maintenance therapy, daily dose may be increased by 10–40% if needed; if person experiences adverse effects, dosage may be decreased by 10–20%. Maintenance dosages have ranged from 12 to 1500 mcg daily; however, experience with dosages over 1000 mcg daily is limited. Most individuals need 300 to 800mcg daily. Adjust-a-dose: For individuals with impaired renal function, oral and intrathecal dose must be decreased. Action Hyperpolarises muscle fibres to reduce impulse transmission. Appears to reduce transmission of impulses from spinal cord to skeletal muscle. Route Onset Peak Duration PO Hrs–wks 2–3 hrs Unknown Intrathecal 0.5–1 hr 4 hrs 4–8 hrs Adverse reactions CNS: drowsiness, dizziness, headache, weak­ ness,fatigue, hypotonia, confusion, insomnia, dysarthria, seizures.

Combination products None.

baclofen Clofen, Lioresal, Lioresal Intrathecal, Pacifen, Stelax Pregnancy risk category B3 Use in sport: Permitted Available forms Intrathecal injection: 0.5 mg/mL, 10 mg/5 mL, 10 mg/20 mL Tablets: 10 mg, 25 mg Indications & dosages ➤ Spasticity in multiple sclerosis, spinal cord injury— Adults: Initially, 5mg PO t.i.d. for 3 days, then 10 mg t.i.d. for 3 days, 15 mg t.i.d. for 3 days, 20 mg t.i.d. for 3 days. Dosage increased based on response, up to maximum of 80 mg daily. ➤ Management of severe spasticity in individuals who do not respond to or cannot tolerate oral baclofen therapy— Adults: Screening phase— After test dose to check responsiveness, drug is given by implantable infusion pump. Test dose is 1 mL of a 50-mcg/mL dilution administered into intrathecal space by barbotage over 1 minute or more. Significantly decreased

Reactions may be common , uncommon, life-threatening , or commonandlife-threatening.