Nifedipine

General

• Type: Calcium Channel Blocker, Dihydropyridine
• Dosage Forms: 10,20; 30,60,90 ER PO
• Common Trade Names: Procardia, Nifediac, Nifedical, Adalat, Afeditab

Adult Dosing

Preterm labor/Tocolysis

• 20mg x1, additional 20mg dose in 90min if ctx persist, followed by 20mg q3-8 hrs prn ctx

Pediatric Dosing

Hypertensive emergency

• 0.25-0.5 mg/kg PO q4-6h
• Max: 10 mg/dose up to 1-2 mg/kg/day

Hypertrophic cardiomyopathy

• 0.6-0.9 mg/kg/day PO divided tid-qid

Special Populations

• Pregnancy Rating: C
• Lactation: Probably safe
• Renal Dosing
  • Adult: no adjustment
  • Pediatric: no adjustment
• Hepatic Dosing
  • Adult: not defined
  • Pediatric: not defined

Contraindications

• Allergy to class/drug
• galactose intolerance (lactose-containing forms)
• hypertensive crisis (IR form)
• HTN (IR form)
• caution if CHF
• caution if aortic stenosis
• caution if hypotension
• caution if renal impairment
• caution if hepatic impairment
• caution if anesthesia or surgery
• caution if concurrent or recent beta blocker use
• caution if GI stricture, severe (XL form)
• caution if GI hypomotility disorder (XL form)
• caution in elderly patients

Adverse Reactions

Serious

• CHF
• pulmonary edema
• MI
• arrhythmias
• hypotension, severe
• cholestasis
• allergic hepatitis
• angioedema
• anaphylaxis
• Stevens-Johnson syndrome
• exfoliative dermatitis
• toxic epidermal necrolysis
• exanthematous pustulosis, acute generalized
• GI obstruction (XL form)
• GI ulcer (XL form)

Common

• peripheral edema
• headache
• dizziness
• flushing
• fatigue/weakness
• nausea
• constipation
• muscle cramps
• nervousness
• palpitations
• dyspnea
• nasal congestion
• hypotension, transient
• eczematous eruptions (chronic use, elderly patients)

Pharmacology

• Half-life: 2h, 7h (ER)
• Metabolism: liver, CYP450: 3A4 substrate
• Excretion: urine 60-80% (<0.1% unchanged), bile/feces 20%
• Mechanism of Action: inhibits calcium ion influx into vascular smooth muscle and myocardium