Anthropometric Measurements as Predictors of Low Birth Weight Among Tanzanian Neonates: A Hospital-Based Study
November 7, 2025
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Brand Name :
Revatio
(United States) [Available] ,Viagra
(United States) [Available]Synonyms :
sildenafil
Class :
Phosphodiesterase-5 Enzyme Inhibitors; PAH, PDE-5 Inhibitors;
Brand Name :
Revatio
(United States) [Available] ,Viagra
(United States) [Available]Synonyms :
sildenafil
Class :
Phosphodiesterase-5 Enzyme Inhibitors; PAH, PDE-5 Inhibitors;
Dosage forms & StrengthsÂ
Tablet (Revatio)Â
20mgÂ
Tablet (Viagra)Â
20mgÂ
25mgÂ
50mgÂ
100mgÂ
Intravenous solutionÂ
0.8mg/mlÂ
Oral suspensionÂ
10 mg/mlÂ
For erectile dysfunction, only Viagra is indicated
50 mg orally an hour before sexual intercourse
Time of administration may also range from 30 minutes to 4 hours before the sexual intercourse
Dose can be increased to 100 mg or decreased to 25 mg based on the efficacy and tolerance
Pulmonary Arterial HypertensionÂ
For PAH, only Revatio is indicated, to delay the clinical worsening and improve clinical worsening
20 mg orally 3 times daily
If required, titrate the dose up to 80 mg 3 times daily
10 mg intravenous bolus 3 times daily
10 mg intravenous dose is predicted bioequivalent to 10 mg oral dose
Oral and intravenous doses should not exceed the recommended regimen
Pulmonary Arterial HypertensionÂ
In the case of severe hepatic impairment like cirrhosis, keep an initial dose of 25 mg (for Viagra)
In the case of severe renal impairment, keep an initial dose of 25 mg (for Viagra)
:
For PAH, only Revatio is indicated, to delay the clinical worsening and improve clinical worsening
20 mg orally 3 times daily
If required, titrate the dose up to 80 mg 3 times daily
10 mg intravenous bolus 3 times daily
10 mg intravenous dose is predicted bioequivalent to 10 mg oral dose
Oral and intravenous doses should not exceed the recommended regimen
Dosage forms & StrengthsÂ
Tablet (Revatio)Â
20mgÂ
Tablet (Viagra)Â
20mgÂ
25mgÂ
50mgÂ
100mgÂ
Intravenous solutionÂ
0.8mg/mlÂ
Oral suspensionÂ
10 mg/mlÂ
Pulmonary Arterial HypertensionÂ
No dose adjustment is required in the case of renal or hepatic impairment:
Revatio is indicated for children of 1-17 years to treat pulmonary arterial hypertension For <20 kg: 10 mg orally 3 times daily For 20-45 kg: 20 mg orally 3 times daily For ≥45 kg: 20 mg orally 3 times daily In pediatrics, maximum dose cannot be identified
Dosage forms & StrengthsÂ
Tablet (Revatio)Â
20mgÂ
Tablet (Viagra)Â
20mgÂ
25mgÂ
50mgÂ
100mgÂ
Intravenous solutionÂ
0.8mg/mlÂ
Oral suspensionÂ
10 mg/mlÂ
Only Viagra is indicated for erectile dysfunction
For ≥65 years: Initially, 25 mg orally an hour before sexual intercourse
Time of administration may also range from 30 minutes to 4 hours before the sexual intercourse
Dose can be increased to 100 mg or decreased to 25 mg based on the efficacy and tolerance
Pulmonary Arterial HypertensionÂ
Revatio is only indicated for PAH to delay clinical worsening and improve exercise ability
20 mg orally 3 times daily
If required, titrate the dose up to 80 mg orally 3 times daily based on tolerance and symptoms
10 mg intravenous bolus 3 times daily
10 mg intravenous dose is predicted
bioequivalent to 10 mg oral dose
Oral and intravenous doses should not exceed the recommended regimen
May increase the vasodilatory effect when combined with Vasodilators
May increase the vasodilatory effect when combined with Vasodilators
nafcillin will decrease the effect of action of sildenafil by affecting enzyme CYP3A4 metabolism.
CYP3A strong enhancers of the small intestine may reduce the bioavailability of sildenafil
amyl nitrite: they may increase the vasodilatory effect when combined with Phosphodiesterase 5 Inhibitors
may enhance the hypotensive effect of Alpha1-Blockers
bunazosin (Not available in the United States)
may enhance the hypotensive effect of Alpha1-Blockers
may enhance the hypotensive effect of Alpha1-Blockers
may enhance the hypotensive effect of Alpha1-Blockers
may enhance the hypotensive effect of Alpha1-Blockers
may enhance the hypotensive effect
may enhance the hypotensive effect
may enhance the hypotensive effect
may enhance the hypotensive effect
may enhance the hypotensive effect
may increase the vasodilatory effect
may increase the vasodilatory effect
may increase the vasodilatory effect
may increase the vasodilatory effect
may increase the vasodilatory effect
may increase the vasodilatory effect
may increase the vasodilatory effect
may increase the vasodilatory effect
sildenafil: they may diminish the serum concentration of CYP3A4 Inducers
sildenafil: they may diminish the serum concentration of CYP3A4 Inducers
sildenafil: they may diminish the serum concentration of CYP3A4 Inducers
sildenafil: they may diminish the serum concentration of CYP3A4 Inducers
sildenafil: they may diminish the serum concentration of CYP3A4 Inducers
Phosphodiesterase 5 Inhibitors: they may increase the hypotensive effect when combined with blood viscosity reducing agents
Phosphodiesterase 5 Inhibitors: they may increase the hypotensive effect when combined with blood viscosity reducing agents
may have an increased hypotensive effect when combined with anti-hypertensive agents
the effect of sildenafil is decreased by lorlatinib, by altering intestinal or hepatic CYP3A4 enzyme metabolism
idelalisib increases the effect or level of sildenafil by altering the intestinal/hepatic CYP3A4 metabolism
CYP3A4 inhibitors increase the concentration of sildenafil in serum
may enhance the serum concentration of CYP3A4 inhibitors
may enhance the effect of vasodilators
may enhance the effect of vasodilators
may enhance the effect of vasodilators
may enhance the effect of vasodilators
may enhance the effect of vasodilators
may increase the hypotensive effect of Blood Pressure Lowering Agents
may increase the hypotensive effect of Blood Pressure Lowering Agents
when nicorandil is combined or used concurrently with phosphodiesterase 5 inhibitors, it can lead to a decrease in blood pressure, which is called the synergic effect
Actions and Spectrum:Â
sildenafil is a medication that is primarily used to treat erectile dysfunction (ED) in men. It works by relaxing the blood vessels in the penis, allowing for increased blood flow and improved ability to achieve and maintain an erection.Â
Aside from treating ED, sildenafil can also be used to treat pulmonary arterial hypertension (PAH), a condition characterized by high blood pressure in the arteries that supply the lungs. In PAH, sildenafil helps to relax the blood vessels in the lungs, allowing for improved blood flow and reduced blood pressure.Â
The spectrum of sildenafil is relatively narrow, as it primarily acts on the blood vessels in the penis and lungs. However, it may also have some effects on other parts of the body, such as the heart and blood vessels in other areas.Â
Frequency definedÂ
>10%Â
Headache Â
Flushing Â
Headache Â
Flushing Â
Dyspepsia Â
Abnormal vision Â
1-10%Â
Dyspepsia Â
Nasal congestionÂ
Back painÂ
Dizziness Â
Nausea Â
Abnormal visionÂ
MyalgiaÂ
Rash Â
<1%Â
Flushing Â
Epistaxis Â
Diarrhea Â
Insomnia Â
MyalgiaÂ
Dyspnea exacerbates Â
Erythema Â
Pyrexia Â
Rhinitis Â
Gastritis Â
Sinusitis Â
Paresthesia
There is no blackbox warning for the drugÂ
Contraindication/Caution:Â
Contraindications:Â
Caution:Â
Pregnancy consideration:Â Â
Not recommended to be used in pregnant womenÂ
Breastfeeding warnings:Â Â
It is excreted in breastmilk, hence not recommended to be used in lactating womenÂ
Pregnancy category:Â
Pharmacology:Â
sildenafil is a phosphodiesterase type 5 (PDE5) inhibitor, which means it works by blocking the action of the PDE5 enzyme. PDE5 is responsible for breaking down cyclic guanosine monophosphate (cGMP), a molecule that helps to relax the smooth muscles in the blood vessels, including those in the penis and lungs. Â
When sildenafil is taken, it inhibits the PDE5 enzyme, allowing for increased levels of cGMP in the blood vessels. This leads to relaxation of the smooth muscles and increased blood flow to the penis, which helps to improve erectile function. In the lungs, increased cGMP levels result in relaxation of the blood vessels and reduced blood pressure, which helps to treat pulmonary arterial hypertension (PAH). Â
sildenafil is rapidly absorbed into the bloodstream after oral administration and reaches peak plasma concentrations within 30-120 minutes. It is metabolized in the liver and excreted mainly in the feces, with a small amount excreted in the urine. The half-life of sildenafil is approximately 4 hours, which means that it is eliminated from the body relatively quicklyÂ
Pharmacodynamics:Â
The pharmacodynamics of sildenafil refers to how the drug works in the body and its effects on various physiological processes.Â
As a PDE5 inhibitor, sildenafil increases the levels of cyclic guanosine monophosphate (cGMP) in the blood vessels, which leads to smooth muscle relaxation and increased blood flow. In the penis, this results in improved erectile function, while in the lungs, it helps to reduce pulmonary arterial hypertension (PAH) by relaxing the blood vessels and lowering blood pressure.Â
In addition to its effects on cGMP, sildenafil may also have some effects on other pathways in the body. For example, it may increase the release of nitric oxide, a signaling molecule that plays a role in regulating blood vessel function. It may also affect other PDE enzymes, such as PDE3, which are involved in regulating heart and cardiovascular function.Â
Pharmacokinetics:Â
AbsorptionÂ
The bioavailability is 40%Â
DistributionÂ
The peak plasma time is 30-120 minÂ
MetabolismÂ
Drug is metabolized in the liver by CYP3A4 and CYP2C9Â
Metabolite formed is N-desmethyl Â
Elimination and ExcretionÂ
The half-life is 3-4 hour for parent drug and for active metabolite is 10-70 minutesÂ
The drug is excreted 80% in feces and 13% in urine
Administration:Â
sildenafil is typically administered orally in the form of tablets or capsules. The dose and frequency of administration depend on the condition being treated and individual factors such as age and health status.Â
For the treatment of erectile dysfunction, the recommended starting dose of sildenafil is usually 50 mg taken approximately 1 hour before sexual activity. The dose may be adjusted based on the individual’s response and tolerability, up to a maximum dose of 100 mg per day. sildenafil should not be taken more than once per day.Â
For the treatment of pulmonary arterial hypertension (PAH), the recommended dose of sildenafil is typically 20 mg three times per day, with a maximum dose of 80 mg per day.Â
sildenafil should be taken on an empty stomach, as food can delay the absorption and reduce the effectiveness of the drug. It should be swallowed whole with a full glass of water.Â
It is important to follow the dosing instructions provided by a healthcare provider and not to exceed the recommended dose. Taking too much sildenafil can increase the risk of side effects, including headache, flushing, and low blood pressure.Â
sildenafil should not be taken with nitrates, as this combination can cause a dangerous drop in blood pressure. It should also not be taken with certain medications, such as alpha-blockers and certain antifungal medications, without the guidance of a healthcare provider.Â
Patient information leafletÂ
Generic Name: sildenafilÂ
Pronounced: sil-DEN-a-filÂ
Why do we use sildenafil?Â
sildenafil is primarily used to treat two main conditions:Â
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