But it can't be sniffed in that form (as a powder), it has to be heated and vaporised for effective absorption. The vapour is absorbed more rapidly directly into mucous membranes, making a faster hit.
- Sildenafil may interact with other medications, increasing risks.
- Significant interactions include nitrates and alpha-blockers.
- Patients should disclose all medications to their doctor.
- Combining with certain drugs can cause dangerous drops in blood pressure.
- Regular liver function monitoring may be necessary.
- Some herbal supplements also have interaction potential.
- Avoiding certain foods and medications reduces risks.
- Proper management improves treatment efficacy.
But this isn't as convenient as sniffing a finely ground powder and would not be a convenient way to distribute legal pharmaceuticals (imagine the police attention if you had to heat a spoon full of fluticasone to relieve your blocked nose).
- The discovery of sildenafil began with research on heart drugs.
- It was found to cause vasodilation as a side effect.
- Pfizer refined the drug for erectile dysfunction.
- It became a blockbuster drug upon FDA approval.
- Sildenafil has helped millions worldwide.
- It has changed perceptions about male sexual health.
- Ongoing research explores new formulations.
- Awareness campaigns promote safe usage.
So, in short, convenience of manufacture and delivery frequently lead to the ideal form of a drug being a salt and not the pure active ingredient. So from my understanding, Amines are easier to purify with their salt form, and the salt form are more soluble than Amines, is it right? $\endgroup$ChemicalFool– ChemicalFool2017-10-30 20:26:35 +00:00Commented Oct 30, 2017 at 20:26 2$\begingroup$ Another beautiful feature about crystals is that a simple visual inspection will often be enough to determine that the reaction proceeded as intended. $\endgroup$Jan– Jan2017-10-31 06:24:43 +00:00Commented Oct 31, 2017 at 6:24 1$\begingroup$ The stability of the free base may be lower than the salt form $\endgroup$Waylander– Waylander2017-10-31 10:24:22 +00:00Commented Oct 31, 2017 at 10:24 Sildenafil Citrate is one and the same thing (at least in pharmaceutical marketing) as Sildenafil 1-[4-ethoxy-3-(6,7-dihydro-1-methyl-7-oxo-3-propyl-1H-pyrazolo[4,3-d]pyrimidin-5-yl)-phenylsulfonyl]-4-methylpiperazine citrate. In pharmaceutical products there are several considerations that influence salt selection. Many synthetic substances to be used in solid dosage form are too limited in solubility to be therapeutically effective. [1] Salts are most frequently employed for altering aqueous solubility; however, selected salt forms also influence a range of other properties such as melting point, chemical stability, hygroscopicity, solution pH, dissolution rate, crystal form and mechanical properties. Different salt forms may have different stability characteristics. Generally speaking, different salt forms of the same drug rarely differ pharmacologically, unless the dose is sufficiently high such as to render the counterion toxic or pharmacologically active.
What other drugs will affect sildenafil?
The illegal drug cocaine is an interesting case. It is easy to maufacture it as a salt and it is commonly available as the hydrochloride. The hydrochloride dissolves in nasal linings giving a high. But some prefer a faster, more intense (and also, unfortunately, more addictive) high obtained by using the vaporised freebased amine. This is easy to make by reacting the hydrochloride with household baking powder. Rather, the onset and intensity of the drug plasma concentration is that which may be considerably different between different salt forms, as well as between a salt and its free acid or free base.
| Product | Dosage | Quantity + Bonus | Price | |
|---|---|---|---|---|
| Kamagra Oral Jelly | 100mg | 90 + 8 Sachets | 303.56€ 289.10€ | |
| Viagra Generic | 100mg | 20 Pills | 45.58€ 43.41€ | |
| Viagra Generic | 200mg | 30 + 2 Pills | 83.07€ 79.11€ | |
| Viagra Generic | 25mg | 120 + 6 Pills | 125.56€ 119.58€ | |
| Viagra Generic | 200mg | 90 + 6 Pills | 170.79€ 162.66€ | |
| Kamagra | 100mg | 32 Pills | 121.24€ 115.47€ | |
| Kamagra | 100mg | 180 + 6 Pills | 436.79€ 415.99€ | |
| Viagra Generic | 50mg | 270 + 8 Pills | 198.48€ 189.03€ | |
| Viagra Generic | 100mg | 360 + 10 Pills | 330.21€ 314.49€ | |
| Viagra Generic | 50mg | 360 + 10 Pills | 225.33€ 214.60€ | |
| Viagra Generic | 150mg | 120 + 8 Pills | 177.58€ 169.12€ | |
| Kamagra Polo | 100mg | 60 + 4 Pills | 189.39€ 180.37€ | |
| Kamagra | 100mg | 20 Pills | 86.09€ 81.99€ |
If the improvement in bioavailability of the drug is significant, certain pharmacological responses may be elicited as a result. Salt stability can be related to factors such as melting point, solubility, hygroscopicity, and microenvironmental pH. [2] Pharmaceutical salts frequently exist as hydrates, which create difficulties during formulation development, particularly in wet granulation. It often becomes difficult to monitor and control the anhydrate/hydrate form during the wet mixing, fluid bed drying and aqueous film coating processes.
- Sildenafil works by inhibiting phosphodiesterase type 5 enzyme.
- This inhibition increases cGMP levels in the body.
- Elevated cGMP leads to smooth muscle relaxation.
- It promotes vasodilation in the corpus cavernosum.
- This process facilitates an erection during sexual activity.
- The drug’s pharmacokinetics allow for rapid absorption.
- Food intake can influence absorption rate.
- It is effective in men of various ages.
This factor has led to the deselection of a particular salt form in further development process many times. A number of pivotal issues with respect to salt selection for basic sildenafil citrate tablets for female drugs take into consideration the molecular and bulk properties of the material and the impact of the material as a salt form to the pharmacokinetics of the molecule. [4] If a salt has the tendency to form many polymorphs, then, unless production of the desired form can be easily controlled, it should be rejected in favour of one that exhibits less polymorphic behaviour. The decision of whether to develop a salt form or a free form of a drug must also include the cost and feasibility of making the desired form.
- Sildenafil citrate is sometimes used off-label for other conditions.
- Off-label uses include altitude sickness and Raynaud’s phenomenon.
- Research continues into additional therapeutic effects.
- The drug’s development was led by Pfizer.
- It is often used in combination with other ED treatments.
- Patients should avoid grapefruit juice, which can affect drug levels.
- Some formulations include chewable or dissolvable tablets.
- Ongoing studies investigate its cardiovascular benefits.
The feasibility and ease of crystallization of a salt form could be an important factor in the salt selection decision. Since the crystallization process serves the important purpose of purifying a drug substance, a salt form with a higher degree of crystallinity will be preferred from the chemical processing perspective. A less-crystalline salt form may not readily provide the desired chemical purity and could require extensive effort and cost to develop a robust crystallization process. In some cases, however, the most bioavailable form is developed, and appropriate manufacturing and storage conditions are implemented to minimize degradation and conversion to another form.
Other Uses for Sildenafil
∙ Hamilton, J.P. ∙ Sklar, G.N. Sildenafil citrate in the transplant recipient with erectile dysfunction Rostaing, L. ∙ Tran Van, T. ∙ Alder, J.L.
Patient resources
Increased glomerular filtration rate in kidney transplant recipients who take sildenafil Transient renal effects of sildenafil in male kidney transplant recipients ↑ Masse molaire calculée d’après « Atomic weights of the elements 2007 », sur ↑ (en) Matthew J Taylor, Lisa Rudkin, Philippa Bullemor-Day et Jade Lubin, « Strategies for managing sexual dysfunction induced by antidepressant medication », Cochrane Database of Systematic Reviews, vol. ↑ Richard E. Moon, Stefanie D. Martina, Dionne F. Peacher et Jennifer F.
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Potter, « Swimming-Induced Pulmonary Edema », Circulation, vol. (2004) « Is Viagra a viable conservation tool? Response to Hoover » Environmental Conservation 31(1):4-6. & von Hippel, W. (2002) « Sex, drugs, and animal parts: Will Viagra save threatened species? The decision to investigate salt forms should be driven by the intended use and properties of the drug, such as the pKa, which will influence the selection of counterions used to make salts and the tendency of the salt form to disproportionate as well as other important factors such as economic viability etc [2] Adeyeye, Moji Christianah; Brittain Harry, G. (2008). Preformulation in Solid Dosage Form Development (Vol. New York, NY 10017: Informa Healthcare USA, Inc. Expert Opinion on Drug Delivery, 10(9), 1239-1257. Sildenafil oral tablet is available as a brand-name drug and as a generic drug. Sildenafil comes in three forms: an oral tablet, an oral suspension (liquid), and an injection that’s only given by a doctor. Sildenafil oral tablet is used to treat erectile dysfunction (ED).
| Parameter | Value | Description | Notes |
|---|---|---|---|
| Absorption | Rapid | Peak plasma levels in 30-120 mins | After oral administration |
| Bioavailability | 40% | Percentage of dose reaching systemic circulation | Subject to food effects |
| Half-life | 4 hours | Time for plasma concentration to reduce by half | --- |
| Metabolism | Liver (CYP3A4 enzymes) | Mainly via CYP3A4 and CYP2C9 | |
| Excretion | Feces and urine | 80% via feces, 13% via urine |
It’s also used to treat pulmonary arterial hypertension (PAH). It comes in the form of a tablet and suspension (liquid).
Adverse effects
↑ (en) von Hippel, W., von Hippel, F.A., Chan, N. & Cheng, C. (2005) « Exploring the use of Viagra in place of animal and plant potency products in traditional Chinese medicine » Environmental Conservation 32(3):235-238. New England Journal of Medicine 353:2148–2157. Safety, tolerability and pharmacokinetics of an intravenous bolus of sildenafil in patients with pulmonary arterial hypertension.
Interactions that increase your risk for side effects
British Journal of Clinical Pharmacology 71:289–292. The data I found seems sildenafil 130mg to show no difference between Sildenafil and Sildenafil citrate. But if they are the same things, why Pfizer use Sildenafil citrate instead of Sildenafil as their product Viagra? 1$\begingroup$ Amines are generally used as their salts. $\endgroup$Mithoron– Mithoron2017-10-30 15:14:28 +00:00Commented Oct 30, 2017 at 15:14 1$\begingroup$ Different topic, but the answer to this question might be relevant.
Clinical monitoring
$\endgroup$paracetamol– paracetamol2017-10-30 15:35:44 +00:00Commented Oct 30, 2017 at 15:35 1$\begingroup$ Also chemistry.stackexchange.com/questions/9499/… $\endgroup$Mithoron– Mithoron2017-10-30 16:19:28 +00:00Commented Oct 30, 2017 at 16:19 1$\begingroup$ Also be aware that several companies and medical sites will frequently refer to their active ingredient without the counterion e.g. for Nimbex, you'll see cisatracurium rather than cisatracurium besylate. Hence why colloquially, Viagra 's API is referred to as sildenafil. $\endgroup$Beerhunter– Beerhunter2017-10-31 07:53:41 +00:00Commented Oct 31, 2017 at 7:53 In many pharmaceuticals (and many recreational drugs) the choice of form is determined by the convenience of the manufacturing and delivery Many drugs (not just sildenafil) are manufactured as salts or simple derivatives of the active molecule. For example, the anti-inflammatory steroid fluticasone is usually delivered as the propionate or furoate esters and the recreational drug cocaine is usually delivered as the hydrochloride salt. It also comes in an intravenous (IV) form, which is only given by a doctor.
| Parameter | Frequency | Purpose | Notes |
|---|---|---|---|
| Blood Pressure | Before and after dosage | Check for hypotension | Especially in high-risk groups |
| Visual Function | Periodic | Monitor for retinal issues | Baseline and follow-up |
| Liver Function Tests | As needed | Detect hepatotoxicity | For long-term users |
Sildenafil oral tablet is available as the brand-name drugs Viagra and Revatio. It’s also available as a generic drug.
Monographie du produit
In all this cases the active ingredient is exactly the same in the body. But there are two factors that matter as well as the active ingredient. One is how easy it is to obtain a convenient form that is pure and easy to make. Amines, for example, are much less prone to produce nice crystals than their salts (sildenafil and cocaine are amines). Since the industry needs to have a good route to a verifiably pure compound and since crystallisation is a good way to obtain pure compounds, they often experiment with different salts to find one that gives a satisfactory end result.
Statistical Analysis
This is convenient for the manufacturer and makes no difference to the active ingredient which is determined by the pH of the biological environment. The second reason is the ease of delivery of the drug. The physical form and chemistry of the substance or salt do matter for the bioavailability. If the drug is taken as a pill, it has to be well absorbed in the digestive system (which means it should, usually, dissolve quickly in the stomach). Salts are more likely to be rapidly soluble than simple amines (though this depends on the form as much as the fact they are a salt though the form is more controllable if you have nice crystals to start with in manufacturing). Generic drugs usually cost less than the brand-name version.