DrugindexOnline^{2nd edition}

Pronouncation: (A-mill NYE-trite)
Class: Vasodilator, Nitrate

Trade Names:
Amyl Nitrite
- Inhalant 0.3 mL

Mechanism of Action

Pharmacology

Nonspecific relaxation of smooth muscle.

Pharmacokinetics

Absorption

Rapidly absorbed through pulmonary alveoli.

Metabolism

Probably by hydrolytic denitration.

Elimination

Approximately 33% is excreted in the urine.

Onset

0.5 min

Duration

3 to 5 min.

Indications and Usage

Rapid relief of angina pectoris.

Contraindications

Cerebral hemorrhage, glaucoma, recent head trauma, pregnancy.

Dosage and Administration

Adult

Inhalation 0.3 mL as needed; 2 to 6 inhalations from 1 capsule are usually sufficient. May be repeated in 3 to 5 min.

General Advice

• Crush capsule between fingers while holding capsule away from patient's face.
• With patient in seated or lying position, hold crushed capsule under patient's nose and have patient inhale vapors until angina symptoms relieved (2 to 6 inhalations).
• When being administered by someone other than patient, use caution to avoid having patient inhale excessive amounts of drug.

Storage/Stability

Store capsules in refrigerator (36° to 46°F). Protect from light and sources of ignition.

Drug Interactions

Alcohol

Severe hypotension and CV collapse may occur.

Aspirin

Increased nitrate concentration and actions may occur.

Calcium channel blockers

Symptomatic orthostatic hypotension may occur.

Phosphodiesterase type 5 inhibitors (eg, sildenafil, tadalafil, vardenafil)

Because the hypotensive effects of nitrates may be potentiated, concomitant use of any form of organic nitrates is contraindicated in patients receiving phosphodiesterase type 5 inhibitors.

Laboratory Test Interactions

May cause false report of reduced serum cholesterol with Zlatkis-Zak color reaction.

Adverse Reactions

Cardiovascular

Hypotension, syncope, tachycardia.

CNS

Dizziness, headache, restlessness, weakness.

Dermatologic

Flushing.

GI

Nausea, vomiting.

Hematologic

Methemoglobinemia.

Miscellaneous

Cold sweat, involuntary passing of urine and feces, pallor.

Precautions

Pregnancy

Category C .

Lactation

Undetermined.

Children

Safety and efficacy not established.

Angina

May aggravate angina caused by hypertrophic cardiomyopathy.

Drug abuse

May be abused for sexual stimulation or for effects of dizziness, euphoria, and light-headedness.

Flammable

Amyl nitrite is very flammable; do not use where it may become ignited.

Methemoglobinemia

High doses may produce methemoglobinemia, especially in patients with methemoglobin reductase deficiency.

Orthostatic hypotension

May occur even with small doses, particularly if patient is standing immobile; alcohol accentuates this reaction.

Tolerance

May develop with repeated use for prolonged periods of time; minimize tolerance by beginning with smallest effective dose and alternating with another coronary vasodilator.

Overdosage

Symptoms

Violent flushing of the face accompanied by a feeling of imminent bursting of the head and very excessive heart action, a feeling of suffocation, and muscular weakness.

Patient Information

• Advise patient to review patient information leaflet carefully before starting therapy and to read and check for new information each time the medication is refilled.
• Review with patient and family the signs and symptoms of angina (eg, acute onset of pressure-like chest pain that may radiate down the left arm and/or into the neck or jaw, often associated with sweating and shortness of breath or difficulty breathing).
• Instruct patient in proper use of medication: while sitting or lying down, crush glass capsule between fingers while holding capsule away from face; hold crushed capsule under nose and inhale vapors until symptoms of angina are relieved; discard capsule following use.
• Advise patient that medication may be repeated in 3 to 5 min if angina symptoms persist or recur. Instruct patient or caregiver to call 911 if angina symptoms worsen or persist after 2 doses of amyl nitrite.
• Advise patient to notify health care provider if angina symptoms increase in frequency or severity, or if there is a sudden increase in the frequency of use of amyl nitrite.
• Caution patient that medication may cause dizziness, light-headedness, or fainting, especially if used while standing, or following consumption of alcohol.
• Caution patient to avoid sudden position changes to prevent orthostatic hypotension.
• Instruct patient to notify health care provider if any of the following occur after using amyl nitrite: frequent episodes of dizziness or light-headedness, fainting, intolerable headache, episodes of sweating, nausea and/or vomiting, any unusual or unexplained feeling or sensation.
• Caution patient that amyl nitrite is very flammable and to avoid use where it may become ignited.
• Caution patient that this medication must not be taken during pregnancy or when pregnancy is possible. Advise patient to use reliable form of birth control while taking this drug.
• Advise use of acetaminophen for relief of headache.
• Show patient how to crush capsule. Remind patient not to remove cloth-like covering.
• Show patient how to keep record of usage, including frequency, dosage, and level of pain relief.
• Explain potential for abuse.
• Instruct patient to avoid intake of alcoholic beverages or other CNS depressants and aspirin.