Liqrev (sildenafil) suspension is used for pulmonary arterial hypertension (PAH) to improve adult patients' ability to exercise and to delay clinical worsening. Liqrev works by relaxing the muscles in blood vessels so they become wider this lowers blood pressure in the lungs, and it also increases the amount of blood pumped by the heart (cardiac output).

Liqrev is a phosphodiesterase-5 (PDE-5) inhibitor that has its effect by blocking the enzyme PDE-5. Liqrev is available as an oral suspension that is taken three times a day.

Liqrev, received FDA approval on April 28, 2023.

Take this medicine exactly as it was prescribed for you. Follow all directions on your prescription label and read all medication guides or instruction sheets.

Shake the bottle for at least 10 seconds before you measure your dose.

Measure your prescribed dose using an oral dosing syringe. Your dose may be changed by your healthcare provider. Do NOT change your dose or stop taking this medicine without talking to your healthcare provider.

Take your prescribed dose by mouth. Liqrev is usually taken three times a day. 

Usual Adult Liqrev Dose for Pulmonary Hypertension

•  20 mg orally three times a day

Use: Treatment of PAH (WHO Group I) in adults to improve exercise ability and delay clinical worsening.

Liqrev is available as 10 mg/mL oral suspension. 

Do not take Liqrev if you take nitrate medicines either regularly or occasionally, as this can increase your risk of having serious and sudden low blood pressure. Nitrates medicine may include nitroglycerin, isosorbide dinitrate, isosorbide mononitrate, and some recreational drugs such as "poppers".

Some medicines can cause unwanted or dangerous effects when used with sildenafil. Tell your doctor about all your current medicines, especially riociguat (Adempas).

Stop using Liqrev and get emergency medical help if you have sudden vision loss.

Before taking this medicine

You should not use Liqrev if you are allergic to sildenafil, or:

• if you take other medicines to treat pulmonary arterial hypertension, such as riociguat (Adempas).

Do not take sildenafil if you are also using a nitrate drug for chest pain or heart problems. This includes nitroglycerin, isosorbide dinitrate, and isosorbide mononitrate. Nitrates are also found in some recreational drugs such as amyl nitrate or nitrite ("poppers"). Taking sildenafil with nitrate medicine can cause a sudden and serious decrease in blood pressure.

To make sure Liqrev is safe for you, tell your doctor if you have ever had:

• heart problems (chest pain, a heart rhythm disorder, heart attack)
• high or low blood pressure
• blood circulation problems
• retinitis pigmentosa (an inherited condition of the eye)
• blindness in one or both eyes
• bleeding problems
• a stomach ulcer
• pulmonary veno-occlusive disease (PVOD)
• have ever had hearing problems such as ringing in the ears, dizziness, or loss of hearing
• liver or kidney disease
• a blood cell disorder such as sickle cell anemia, multiple myeloma, or leukemia
• a physical deformity of the penis (such as Peyronie's disease).

Sildenafil can decrease blood flow to the optic nerve of the eye, causing sudden vision loss. This has occurred in a small number of people taking sildenafil, most of whom also had heart disease, diabetes, high blood pressure, high cholesterol, or certain pre-existing eye problems, and in those who smoked or were over 50 years old. It is not clear whether this medicine is the actual cause of vision loss.

It is especially important to tell your healthcare provider if you take:

• nitrates or guanylate cyclase stimulators. See “Who should not use Liqrev?”
• medicines to treat high blood pressure
• medicines for erectile dysfunction (impotence). Liqrev contains sildenafil, which is the same medicine found in another medicine called Viagra® which is used for the treatment of erectile dysfunction. Do not take Viagra or other PDE-5 inhibitors including  avanafil (Stendra), tadalafil (Cialis) or vardenafil (Levitra) during treatment with Liqrev.

It is not known if sildenafil is safe and effective in children younger than 1 year of age.

Pregnancy

Tell your doctor if you are pregnant. It is not known whether sildenafil will harm an unborn baby. However, having pulmonary arterial hypertension (PAH) during pregnancy may cause complications such as heart failure, stroke, or medical problems in both mother and baby. The benefit of treating PAH with Liqrev may outweigh any risks to the baby.

Breastfeeding

It may not be safe to breastfeed while using this medicine. Ask your doctor about any risks.

If you miss a dose, take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Drinking alcohol with this medicine can cause side effects.

Grapefruit may interact with this medicine and lead to unwanted side effects. Avoid the use of grapefruit products.

Avoid using any other medicines to treat impotence, such as alprostadil or yohimbine, without first talking to your doctor.

Get emergency medical help if you have signs of an allergic reaction to this medicine: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Stop taking Liqrev and get emergency medical help if you have:

• heart attack symptoms - chest pain or pressure, pain spreading to your jaw or shoulder, nausea, sweating;
• vision changes or sudden vision loss; or
• erection is painful or lasts longer than 4 hours (prolonged erection can damage the penis).

Call your doctor at once if you have:

• severe shortness of breath, cough with foamy mucus;
• ringing in your ears, or sudden hearing loss;
• irregular heartbeat;
• swelling in your hands, ankles, or feet;
• a seizure; or (convulsions); or
• a light-headed feeling, like you might pass out.

Common Liqrev side effects may include:

• flushing (warmth, redness, or tingly feeling);
• headache, dizziness;
• abnormal vision (blurred vision, changes in color vision)
• runny or stuffy nose, nosebleeds;
• sleep problems (insomnia);
• muscle pain, back pain; or upset stomach.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Do not take Liqrev with similar medications such as avanafil (Stendra), tadalafil (Cialis) or vardenafil (Levitra). Tell your doctor about all other medications you use.

Tell your doctor about all your other medicines, especially:

• drugs to treat high blood pressure or a prostate disorder;
• antifungal medicine - ketoconazole or itraconazole; or
• medicine to treat HIV/AIDS - ritonavir and others.

This list is not complete. Other drugs may interact with sildenafil, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.