Laronidase

INTRODUCTION

Indications

Mucopolysaccharidosis I (MPS I; specifically Hurler and Hurler-Scheie form or Scheie form) with moderate to severe symptoms.

Action

Replaces the naturally occurring enzyme α-L-iduronidase which is deficient in MPS I. Without replacement, the glucosaminoglycans dermatan and heparan accumulate in tissues. Therapeutic Effects: Decreased cellular, tissue, and organ damage due to MPS accumulation resulting in improved pulmonary function and walking capacity.

Adverse Reactions/Side Effects

Resp: respiratory tract infections. Derm: rash. Local: injection site reactions. Misc: ALLERGIC REACTIONS, INCLUDING ANAPHYLAXIS, infusion-related reactions.

PHYSICAL THERAPY IMPLICATIONS

Examination and Evaluation

• Monitor signs of allergic reactions and anaphylaxis, including pulmonary symptoms (tightness in the throat and chest, wheezing, cough, dyspnea) or skin reactions (rash, pruritus, urticaria). Be especially alert for allergy-like responses that occur during and after administration (infusion-related reactions). Notify physician immediately if these reactions occur.

• Assess ambulation on level surfaces and during stair climbing. Document any changes in functional ability to help determine if drug therapy is effective in maintaining or improving motor function.

• Assess for signs of respiratory tract infections such as fever, cough, sputum production, shortness of breath, difficulty breathing, and fatigue. Notify physician if these signs occur.

• Monitor IV infusion site for pain, swelling, and irritation. Report prolonged or excessive infusion-site reactions to the physician.

Interventions

• Implement therapeutic exercises (resistive training, coordination exercises, gait training) to complement the effects of drug therapy and help achieve optimal function.

Pharmacokinetics

Absorption: IV administration results in complete bioavailability.

Distribution: Unknown.

Metabolism and Excretion: Unknown.

Half-life: 1.5–3.6 hr.

Contraindications/Precautions

Contraindicated in: None known.

Use Cautiously in: Pregnancy (use only if clearly needed); Lactation (safety not established).

Interactions

Drug-Drug: None known.

Route/Dosage

IV (Adults and Children): 0.58 mg/kg once weekly, pretreat with antipyretics and/or antihistamines.

Availability

Solution for injection: 2.9 mg/5 mL-vial.