GTN 400mcg Spray

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Uses of GTN

• Angina (heart-related chest pain)

Side effects of GTN

Common

• Blurred vision
• Decreased blood pressure
• Dizziness
• Headache
• Increased heart rate
• Lightheadedness
• Paresthesia (tingling or pricking sensation)

How to use GTN

Take this medicine in the dose and duration as advised by your doctor. Swallow it as a whole. Do not chew, crush or break it. GTN may be taken with or without food, but it is better to take it at a fixed time.

How GTN works

GTN is a nitrate. It works by relaxing the blood vessels which decreases the oxygen demand of the heart and reduces its workload, thereby preventing/treating attacks of angina (chest pain).

What if you forget to take GTN?

If you miss a dose of GTN, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular schedule. Do not double the dose.

Quick Tips

GTN may cause dizziness or sleepiness. Do not drive or do anything that requires concentration until you know how it affects you.

Do not consume alcohol while taking GTN as it may cause increased dizziness.

It may cause headaches which usually go away after a few days of continued treatment. Inform your doctor if it persists.

You may develop tolerance to GTN with time, meaning that the same dose may be less effective next time. Follow the prescribed dosing schedule to avoid this.

Stop taking medications (prescribed for erectile dysfunction) like sildenafil or tadalafil while on treatment with GTN as it may cause low blood pressure.

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Indication

Angina pectoris, Acute myocardial infarction, Severe hypertension, Pulmonary edema.

Adult Dose

Oral Stable angina Adult: As SR tab/cap: 2.6-6.4 mg 3-4 times daily, adjust according to response. Max: 26 mg 4 times daily. Sublingual Tablet Angina Pectoris (Acute Relief) 0.5 mg SL q5min up to 3 times; use at first sign of angina Angina Pectoris (Prophylaxis) 1 tablet SL 5-10 minutes before activities likely to provoke angina attacks Sublingual Spray Angina 1-2 spray(s) PRN for angina, may repeat q3-5min, not to exceed 3 sprays in 15 minutes Spray onto or under tongue; do not inhale, expectorate or rinse mouth for 5-10 minutes Seek medical attention if pain persists after 3 doses in 15 minutes Angina, Prophylaxis 1-2 sprays 5-10 minutes before activities likely to cause angina Intravenous Acute myocardial infarction Adult: 10-100 mcg/min, w/ the dose initially at the lower rate, then increase gradually according to response. Induction of hypotension or control of hypertension during surgery Adult: Initially, 5-25 mcg/min, adjust according to response. Usual range: 10-200 mcg/min; doses up to 400 mcg/min may be required in some cases.

Renal Dose

Renal Failure CrCl: 10-50 mL/min: Administer q24-72hr CrCl: <10 mL/min: Administer q72-96hr

Contraindication

Hypersensitivity. Severe hypotension, heart failure, marked anaemia, hypertrophic obstructive cardiomyopathy, cerebral haemorrhage or head trauma, low cardiac output secondary to hypovolaemia, inferior MI with right ventricular involvement, raised intracranial pressure. Concomitant use with phosphodiesterase type-5 inhibitors.

Mode of Action

Glyceryl trinitrate acts on the enzyme nitric oxide stimulating guanylate cyclase in the vascular smooth muscle cells resulting in the relaxation of smooth muscles. It reduces venous return (preload) and facilitates subendocardial blood flow with redistribution into ischaemic areas. It relieves coronary vasospasm and dilates arterioles reducing afterload. It is useful for relief and prevention of anginal attacks.

Precaution

Severe hepatic or renal impairment, hypothyroidism, malnutrition, hypothermia. Cerebrovascular disease, lung disease or cor pulmonale. Pregnancy, lactation, glaucoma, mitral valve prolapse, cardiac tamponade, syncope. Gradual withdrawal in patients who have received prolonged high dose infusions. Avoid prolonged excessive hypotension. Nitrate-free interval is recommended in patients on continuous treatment with nitrates to reduce risk of tolerance. Lactation: not known whether the drug crosses into breast milk, use caution