Methocarbamol

 Action May cause relaxation of skeletal muscle via general CNS depression. Does not directly relax tense skeletal muscles.

 Indications Adjunctive therapy for relief of painful, acute musculoskeletal conditions; ontrol of neuromuscular manifestations of tetanus.

 Contraindications Renal pathologic disorders (parenteral form).

 Route/Dosage

Skeletal Muscle Relaxation

ADULTS: Initial dose: IV/IM 3 g over £ 3 consecutive days. Repeat course after 48 hr lapse if condition persists. PO 1.5 g qid. MAINTENANCE: PO 1 g qid or 750 mg q 4 hr, or 1.5 g tid. For first 48–72 hr, 6–8 g/day is recommended; then reduce to 4 g/day.

Tetanus

ADULTS: IV 1–2 g; additional 1–2 g may be added to infusion up to 3 g total. Repeat q 6 hr until oral form may be administered. CHILDREN: IV/IV infusion 15 mg/kg initially; then 15 mg/kg q 6 hr.

 Interactions None well documented.

 Lab Test Interferences Screening tests for 5-hydroxy-indoleacetic acid or vanillylmandelic acid: Drug may cause color interference.

 Adverse Reactions

CV: Syncope; hypotension; bradycardia. CNS: Dizziness; lightheadedness; vertigo; headache; drowsiness; fainting; ild muscular incoordination; convulsions in epileptic patients. DERM: Urticaria; pruritus; rash; flushing. EENT: Blurred vision; conjunctivitis with nasal congestion; nystagmus; diplopia; etallic taste. GI: GI upset; nausea. OTHER: Thrombophlebitis; pain or sloughing at injection site; anaphylactic reaction; fever.

 Precautions

Pregnancy: Safety not established. Avoid use, if possible. Lactation: Undetermined. Children: Safety and efficacy in children < 12 yr not established, except for management of tetanus.

 Administration/Storage

• Administer parenteral form for no more than 3 days.
• Wait 48 hr before repeating with additional course if needed.
• For parenteral administration, do not administer SC; drug should be given IV or IM.
• Assess patency of IV site prior to administration; if patency is in doubt, start new IV to avoid extravasation.
• Administer via slow IV push or as infusion.
• Infuse in solution of D5W or saline solution £ 1 vial/250 ml.
• Keep prepared infusion at room temperature.
• For IV administration, place patient in recumbent position; ave patient remain recumbent for 10–15 min after administration to prevent orthostatic hypotension.
• Monitor vital signs and IV flow rate.
• For IM administration, inject deeply and do not exceed 5 ml in each gluteal area. Rotate injection sites.
• For oral administration, administer loading dose followed by maintenance dose.
• May crush tablets if necessary.
• Administer with food to decrease stomach upset.
• Store at room temperature.

 Assessment/Interventions

• Obtain patient history, including drug history and any known allergies. Note epilepsy and renal pathologic conditions.
• Perform physical assessment noting muscle tone, range of motion, pain, CNS function, mentation and vital signs.
• Observe IV site for phlebitis.
• Provide safe environment (eg, keep bed in low position with side rails up, instruct patient to call for assistance when rising).
• Move patient slowly from recumbent to sitting or standing position.
• Keep oxygen and epinephrine available in event of anaphylaxis.
• Monitor for effectiveness of drug and side effects, especially dizziness, drowsiness, rash, pruritus, fever and congestion.
• If patient experiences syncope, place in reverse Trendelenburg's position and monitor vital signs.
• Notify physician if patient does not spontaneously recover.
• Notify physician if extravasation occurs.

 Patient/Family Education

• Instruct patient regarding additional therapy recommended to treat muscle spasm such as activity restrictions or physical therapy.
• Advise patient that drug may cause drowsiness, dizziness and lightheadedness and to use caution while driving or performing other tasks requiring mental alertness.
• Caution patient not to discontinue medication abruptly without consulting physician.
• Inform patient that urine may become different or darker color.
• Instruct patient to report these symptoms to physician: skin rash, itching, fever or nasal congestion.
• Caution patient to avoid sudden changes in position to prevent orthostatic hypotension.
• Instruct patient to avoid intake of alcoholic beverages or other CNS depressants.
• Advise patient not to take otc medications without consulting physician.