Category:

• Miscellaneous

Description:

• Antihypertensive; (preferentially dilates arterioles)

Indications:

• Hypertension

Contraindications:

• Coronary artery disease

• Valvular rheumatic heart disease

Precautions:

• Pregnancy category C

• Advanced renal disease, children, pulmonary hypertension

Adverse Reactions (Side Effects):

• CNS: anxiety, dizziness, headache, peripheral neuritis, psychotic reactions, tremor

• CV: angina, edema, flushing, hypotension, palpitations, reflex tachycardia

• EENT: nasal congestion

• GI: anorexia, constipation, diarrhea, hepatitis, paralytic ileus, nausea, vomiting

• GU: urination difficulty

• HEME: agranulocytosis, anemia, eosinophilia, leukopenia

• SKIN: pruritis, rash, urticaria

• MISC: lupus-like syndrome, arthralgia, muscle cramps

Dosage:

Administered orally (tablet), intramuscularly, and intravenously

• Adult:   

  • PO 10mg 4 times daily, increase by 10-25 mg/dose every 2-5 days as needed to max of 300 mg/day

  • IM/IV 10-20mg every 4-6 hours, may increase to 40 mg/dose

• Child:   

  • PO 0.75-1 mg/kg/day divided 2-4 times daily, increase over 3-4 weeks to 7.5 mg/kg/day divided 2-4 times daily if necessary, do not exceed 200 mg/day

  • IM/IV 0.1-0.2 mg/kg/dose every 4-6 hours, do not exceed 20 mg/dose

Special Considerations:

• May cause black stools

•  Take with meals

•  Lupus-like syndrome more common in “slow acetylators” and folling higher doses for prolonged periods

•  Patient to notify clinician of any unexplained prolonged general tiredness, or fever, muscle or joint aching, or chest pain