Cialis

Cialis - General Information

Cialis is an orally adminstered drug used to treat male erectile dysfunction (impotence). It is marketed worldwide under the brand name Cialis. It is a phosphodiesterase 5 (PDE5) inhibitor. Cialis's distinguishing pharmacologic feature is its longer half-life (17.5 hours) compared with Viagra and Levitra (4-5 hours). This longer half-life results in a longer duration of action and is, in part, responsible for the Cialis nickname of the "weekend pill." This longer half-life also is the basis of current investigation for tadalafil's use in pulmonary arterial hypertension as a once-daily therapy. [Wikipedia]

Pharmacology of Cialis

Cialis is used to treat male erectile dysfunction (impotence) and pulmonary arterial hypertension (PAH). Part of the physiological process of erection involves the release of nitric oxide (NO) in the corpus cavernosum. This then activates the enzyme guanylate cyclase which results in increased levels of cyclic guanosine monophosphate (cGMP), leading to smooth muscle relaxation in the corpus cavernosum, resulting in increased inflow of blood and an erection. Cialis is a potent and selective inhibitor of cGMP specific phosphodiesterase type 5 (PDE5) which is responsible for degradation of cGMP in the corpus cavernosum. This means that, with tadalafil on board, normal sexual stimulation leads to increased levels of cGMP in the corpus cavernosum which leads to better erections. Without sexual stimulation and no activation of the NO/cGMP system, tadalafil should not cause an erection.

Cialis for patients

CIALIS (See-AL-iss)

(tadalafil) tablets

Read the Patient Information about CIALIS before you start taking it and again each time you get a refill. There may be new information. You may also find it helpful to share this information with your partner. This leaflet does not take the place of talking with your doctor. You and your doctor should talk about CIALIS when you start taking it and at regular checkups. If you do not understand the information, or have questions, talk with your doctor or pharmacist.

What important information should you know about CIALIS?

CIALIS can cause your blood pressure to drop suddenly to an unsafe level if it is taken with certain other medicines. You could get dizzy, faint, or have a heart attack or stroke.

Do not take CIALIS if you:

• take any medicines called "nitrates."

• use recreational drugs called "poppers" like amyl nitrate and butyl nitrate.

• take medicines called alpha blockers, other than Flomax (tamsulosin HCl) 0.4 mg daily.

Tell all your healthcare providers that you take CIALIS. If you need emergency medical care for a heart problem, it will be important for your healthcare provider to know when you last took CIALIS.

After taking a single tablet, some of the active ingredient of CIALIS remains in your body for more than 2 days. The active ingredient can remain longer if you have problems with your kidneys or liver, or you are taking certain other medications.

What is CIALIS?

CIALIS is a prescription medicine taken by mouth for the treatment of erectile dysfunction (ED) in men.

ED is a condition where the penis does not harden and expand when a man is sexually excited, or when he cannot keep an erection. A man who has trouble getting or keeping an erection should see his doctor for help if the condition bothers him. CIALIS may help a man with ED get and keep an erection when he is sexually excited.

CIALIS does not:

• cure ED

• increase a man's sexual desire

• protect a man or his partner from sexually transmitted diseases, including HIV. Speak to your doctor about ways to guard against sexually transmitted diseases.

• serve as a male form of birth control

CIALIS is only for men with ED. CIALIS is not for women or children. CIALIS must be used only under a doctor's care.

How does CIALIS work?

When a man is sexually stimulated, his body's normal physical response is to increase blood flow to his penis. This results in an erection. CIALIS helps increase blood flow to the penis and may help men with ED get and keep an erection satisfactory for sexual activity. Once a man has completed sexual activity, blood flow to his penis decreases, and his erection goes away.

Who can take CIALIS?

Talk to your doctor to decide if CIALIS is right for you.

CIALIS has been shown to be effective in men over the age of 18 years who have erectile dysfunction, including men with diabetes or who have undergone prostatectomy.

Who should not take CIALIS? Do not take CIALIS if you:

• take any medicines called "nitrates" . Nitrates are commonly used to treat angina. Angina is a symptom of heart disease and can cause pain in your chest, jaw, or down your arm. Medicines called nitrates include nitroglycerin that is found in tablets, sprays, ointments, pastes, or patches. Nitrates can also be found in other medicines such as isosorbide dinitrate or isosorbide mononitrate. Some recreational drugs called "poppers" also contain nitrates, such as amyl nitrate and butyl nitrate. Do not use CIALIS if you are using these drugs. Ask your doctor or pharmacist if you are not sure if any of your medicines are nitrates.

• take medicines called "alpha blockers", other than Flomax® 0.4 mg daily. Alpha blockers are sometimes prescribed for prostate problems or high blood pressure. If CIALIS is taken with alpha blockers other than Flomax 0.4 mg daily, your blood pressure could suddenly drop to an unsafe level. You could get dizzy and faint.

• you have been told by your healthcare provider to not have sexual activity because of health problems. Sexual activity can put an extra strain on your heart, especially if your heart is already weak from a heart attack or heart disease.

• are allergic to CIALIS or any of its ingredients. The active ingredient in CIALIS is called tadalafil. See the end of this leaflet for a complete list of ingredients.

What should you discuss with your doctor before taking CIALIS?

Before taking CIALIS, tell your doctor about all your medical problems, including if you:

• have heart problems such as angina, heart failure, irregular heartbeats, or have had a heart attack. Ask your doctor if it is safe for you to have sexual activity.

• have low blood pressure or have high blood pressure that is not controlled

• have had a stroke

• have liver problems

• have kidney problems or require dialysis

• have retinitis pigmentosa, a rare genetic (runs in families) eye disease

• have stomach ulcers

• have a bleeding problem

• have a deformed penis shape or Peyronie's disease

• have had an erection that lasted more than 4 hours

• have blood cell problems such as sickle cell anemia, multiple myeloma, or leukemia

Can other medications affect CIALIS?

Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements. CIALIS and other medicines may affect each other. Always check with your doctor before starting or stopping any medicines. Especially tell your doctor if you take any of the following:

• medicines called nitrates

• medicines called alpha blockers. These include Hytrin® (terazosin), Flomax® (tamsulosin), Cardura® (doxazosin), Minipress® (prazosin) or Uroxatral® (alfuzosin).

• ritonavir (Norvir®) or indinavir (Crixivan)

• ketoconazole or itraconazole (such as Nizoral® or Sporanox®)

• erythromycin

• other medicines or treatments for ED

How should you take CIALIS?

Take CIALIS exactly as your doctor prescribes. CIALIS comes in different doses (5 mg, 10 mg, and 20 mg). For most men, the recommended starting dose is 10 mg. CIALIS should be taken no more than once a day. Some men can only take a low dose of CIALIS because of medical conditions or medicines they take. Your doctor will prescribe the dose that is right for you.

• If you have kidney problems, your doctor may start you on a lower dose of CIALIS.

• If you have kidney or liver problems or you are taking certain medications, your doctor may limit your highest dose of CIALIS to 10 mg and may also limit you to one tablet in 48 hours (2 days) or one tablet in 72 hours (3 days). Take one CIALIS tablet before sexual activity. In some patients, the ability to have sexual activity was improved at 30 minutes after taking CIALIS when compared to a sugar pill. The ability to have sexual activity was improved up to 36 hours after taking CIALIS when compared to a sugar pill. You and your doctor should consider this in deciding when you should take CIALIS prior to sexual activity. Some form of sexual stimulation is needed for an erection to happen with CIALIS. CIALIS may be taken with or without meals.

Do not change your dose of CIALIS without talking to your doctor. Your doctor may lower your dose or raise your dose, depending on how your body reacts to CIALIS.

Do not drink alcohol to excess when taking CIALIS (for example, 5 glasses of wine or 5 shots of whiskey). When taken in excess, alcohol can increase your chances of getting a headache or getting dizzy, increasing your heart rate, or lowering your blood pressure.

If you take too much CIALIS, call your doctor or emergency room right away.

What are the possible side effects of CIALIS?

The most common side effects with CIALIS are headache, indigestion, back pain, muscle aches, flushing, and stuffy or runny nose. These side effects usually go away after a few hours. Patients who get back pain and muscle aches usually get it 12 to 24 hours after taking CIALIS. Back pain and muscle aches usually go away by themselves within 48 hours. Call your doctor if you get a side effect that bothers you or one that will not go away.

CIALIS may uncommonly cause:

•an erection that won't go away (priapism) - If you get an erection that lasts more than 4 hours, get medical help right away. Priapism must be treated as soon as possible or lasting damage can happen to your penis including the inability to have erections.

•vision changes - such as seeing a blue tinge to objects or having difficulty telling the difference between the colors blue and green. These are not all the side effects of CIALIS. For more information, ask your doctor or pharmacist.

How should CIALIS be stored?

• Store CIALIS at room temperature between 59 and 86 F (15 and 30 C).

• Keep CIALIS and all medicines out of the reach of children.

General Information about CIALIS:

Medicines are sometimes prescribed for conditions other than those described in patient information leaflets. Do not use CIALIS for a condition for which it was not prescribed. Do not give CIALIS to other people, even if they have the same symptoms that you have. It may harm them.

This leaflet summarizes the most important information about CIALIS. If you would like more information, talk with your healthcare provider. You can ask your doctor or pharmacist for information about CIALIS that is written for health professionals.

For more information you can also visit www.cialis.com, or call 1-877-242-5441.

What are the ingredients of CIALIS?

Active Ingredient: tadalafil

Inactive Ingredients: croscarmellose sodium, hydroxypropyl cellulose, hypromellose, iron oxide, lactose monohydrate, magnesium stearate, microcrystalline cellulose, sodium lauryl sulfate, talc, titanium dioxide, and triacetin.

Norvir® (ritonavir) and Hytrin® (terazosin) are registered trademarks of Abbott Laboratories Crixivan® (indinavir sulfate) is a registered trademark of Merck & Co., Inc. Nizoral® (ketoconazole) and Sporanox® (itraconazole) are registered trademarks of Janssen Pharmaceutica, Inc. Flomax® (tamsulosin) is a registered trademark of Boehringer Ingelheim Pharmaceuticals, Inc. Cardura® (doxazosin) and Minipress® (prazosin) are registered trademarks of Pfizer, Inc. Uroxatral® (alfuzosin) is a registered trademark of Sanofi-Synthelabo

Cialis Interactions

Effects of Other Drugs on Tadalafil
Cytochrome P450 Inhibitors:
Tadalafil is a substrate of and predominantly metabolized by CYP3A4. Studies have shown that drugs that inhibit CYP3A4 can increase tadalafil exposure.
Ketoconazole (400 mg daily), a selective and potent inhibitor of CYP3A4, increased tadalafil 20-mg single-dose exposure (AUC) by 312% and Cmax by 22%, relative to the values for tadalafil 20 mg alone. Ketoconazole (200 mg daily) increased tadalafil 10-mg single-dose exposure (AUC) by 107% and Cmax by 15%, relative to the values for tadalafil 10 mg alone.
HIV Protease inhibitor: Ritonavir (200 mg twice daily), an inhibitor of CYP3A4, CYP2C9, CYP2C19, and CYP2D6, increased tadalafil 20-mg single-dose exposure (AUC) by 124% with no change in Cmax, relative to the values for tadalafil 20 mg alone. Although specific interactions have not been studied, other HIV protease inhibitors would likely increase tadalafil exposure.
Based upon these results, in patients taking concomitant potent CYP3A4 inhibitors, the dose of Tadalafil should not exceed 10 mg, and Tadalafil should not be taken more frequently than once in every 72 hours.
Other cytochrome P450 inhibitors: Although specific interactions have not been studied, other CYP3A4 inhibitors, such as erythromycin, itraconazole, and grapefruit juice, would likely increase tadalafil exposure.
Cytochrome P450 Inducers:
Studies have shown that drugs that induce CYP3A4 can decrease tadalafil exposure.
Rifampin: Rifampin (600 mg daily), a CYP3A4 inducer, reduced tadalafil 10-mg single-dose exposure (AUC) by 88% and Cmax by 46%, relative to the values for tadalafil 10 mg alone. Although specific interactions have not been studied, other CYP3A4 inducers, such as carbamazepine, phenytoin, and phenobarbitol, would likely decrease tadalafil exposure. No dose adjustment is warranted.
Gastrointestinal Drugs:
H2 antagonists: An increase in gastric pH resulting from administration of nizatidine had no significant effect on tadalafil pharmacokinetics.
Antacids: Simultaneous administration of an antacid (magnesium hydroxide/aluminum hydroxide) and tadalafil reduced the apparent rate of absorption of tadalafil without altering exposure (AUC) to tadalafil.
Effects of Tadalafil on Other Drugs:
Drugs Metabolized by Cytochrome P450
Tadalafil is not expected to cause clinically significant inhibition or induction of the clearance of drugs metabolized by cytochrome P450 (CYP) isoforms. Studies have shown that tadalafil does not inhibit or induce P450 isoforms CYP1A2, CYP3A4, CYP2C9, CYP2C19, CYP2D6, and CYP2E1.
CYP1A2 substrate: Tadalafil had no clinically significant effect on the pharmacokinetics of theophylline. When tadalafil was administered to subjects taking theophylline, a small augmentation (3 beats per minute) of the increase in heart rate associated with theophylline was observed.
CYP3A4 substrates: Tadalafil had no clinically significant effect on exposure (AUC) to midazolam or lovastatin.
CYP2C9 substrate: Tadalafil had no clinically significant effect on exposure (AUC) to S-warfarin or R-warfarin, nor did tadalafil affect changes in prothrombin time induced by warfarin.
Alcohol
Alcohol and PDE5 inhibitors, including tadalafil, are mild systemic vasodilators. The interaction of tadalafil with alcohol was evaluated in 3 clinical pharmacology studies. In 2 of these, alcohol was administered at a dose of 0.7 g/kg, which is equivalent to approximately 6 ounces of 80-proof vodka in an 80-kg male, and tadalafil was administered at a dose of 10 mg in 1 study and 20 mg in another. In both these studies, all patients imbibed the entire alcohol dose within 10 minutes of starting. In one of these two studies, blood alcohol levels of 0.08% were confirmed. In these two studies, more patients had clinically significant decreases in blood pressure on the combination of tadalafil and alcohol as compared to alcohol alone. Some subjects reported postural dizziness, and orthostatic hypotension was observed in some subjects. When tadalafil 20 mg was administered with a lower dose of alcohol (0.6 g/kg, which is equivalent to approximately 4 ounces of 80-proof vodka, administered in less than 10 minutes), orthostatic hypotension was not observed, dizziness occurred with similar frequency to alcohol alone, and the hypotensive effects of alcohol were not potentiated. Tadalafil did not affect alcohol plasma concentrations and alcohol did not affect tadalafil plasma concentrations. Both alcohol and Tadalafil, a PDE5 inhibitor, act as mild vasodilators. When mild vasodilators are taken in combination, blood-pressure-lowering effects of each individual compound may be increased. Substantial consumption of alcohol (e.g., 5 units or greater) in combination with Tadalafil can increase the potential for orthostatic signs and symptoms, including increase in heart rate, decrease in standing blood pressure, dizziness, and headache.
Anti-Hypertensives
PDE5 inhibitors, including tadalafil, are mild systemic vasodilators. Clinical pharmacology studies were conducted to assess the effect of tadalafil on the potentiation of the blood-pressure-lowering effects of selected anti-hypertensive medications.
Alpha Blockers
Doxazosin: When tadalafil 20 mg was administered to healthy subjects taking doxazosin (8 mg daily), an alpha[1]-adrenergic blocker, there was significant augmentation of the blood-pressure-lowering effect of doxazosin.
Tamsulosin: In a clinical pharmacology study, when a single dose of tadalafil 20 mg was administered to healthy subjects taking 0.4 mg once-daily tamsulosin, a selective alpha[1A]-adrenergic blocker, no significant decreases in blood pressure were observed. Therefore, based upon significant augmentation of the blood-pressure-lowering effect of doxazosin, an alpha[1]-adrenergic blocker, and no significant effect seen with 0.4 mg once-daily tamsulosin, a selective alpha[1A]-adrenergic blocker, administration of Tadalafil to patients taking any alpha-adrenergic blocker other than 0.4 mg once-daily tamsulosin is contraindicated.
Other Anti-Hypertensive Agents
Amlodipine: A study was conducted to assess the interaction of amlodipine (5 mg daily) and tadalafil 10 mg. There was no effect of tadalafil on amlodipine blood levels and no effect of amlodipine on tadalafil blood levels. The mean reduction in supine systolic/diastolic blood pressure due to tadalafil 10 mg in subjects taking amlodipine was 3/2 mm Hg, compared to placebo. In a similar study using tadalafil 20 mg, there were no clinically significant differences between tadalafil and placebo in subjects taking amlodipine.
Metoprolol: A study was conducted to assess the interaction of sustained-release metoprolol (25 to 200 mg daily) and tadalafil 10 mg. Following dosing, the mean reduction in supine systolic/diastolic blood pressure due to tadalafil 10 mg in subjects taking metoprolol was 5/3 mm Hg, compared to placebo.
Bendrofluazide: A study was conducted to assess the interaction of bendrofluazide (2.5 mg daily) and tadalafil 10 mg. Following dosing, the mean reduction in supine systolic/diastolic blood pressure due to tadalafil 10 mg in subjects taking bendrofluazide was 6/4 mm Hg, compared to placebo.
Enalapril: A study was conducted to assess the interaction of enalapril (10 to 20 mg daily) and tadalafil 10 mg. Following dosing, the mean reduction in supine systolic/diastolic blood pressure due to tadalafil 10 mg in subjects taking enalapril was 4/1 mm Hg, compared to placebo.
Angiotensin II receptor blocker (and other anti-hypertensives): A study was conducted to assess the interaction of angiotensin II receptor blockers and tadalafil 20 mg. Subjects in the study were taking any marketed angiotensin II receptor blocker, either alone, as a component of a combination product, or as part of a multiple anti-hypertensive regimen. Following dosing, ambulatory measurements of blood pressure revealed differences between tadalafil and placebo of 8/4 mm Hg in systolic/diastolic blood pressure.
Aspirin
Tadalafil did not potentiate the increase in bleeding time caused by aspirin.

Cialis Contraindications

Nitrates - Administration of Tadalafil to patients who are using any form of organic nitrate, either regularly and/or intermittently, is contraindicated. In clinical pharmacology studies, tadalafil was shown to potentiate the hypotensive effect of nitrates. This is thought to result from the combined effects of nitrates and tadalafil on the nitric oxide/cGMP pathway.
Alpha Blockers - Administration of Tadalafil to patients taking any alpha-adrenergic antagonist other than 0.4 mg once-daily tamsulosin is contraindicated. In a drug-drug interaction study, when tadalafil 20 mg was administered to healthy subjects taking doxazosin (8 mg daily), there was a significant augmentation of the blood-pressure-lowering effect of doxazosin.
Hypersensitivity - Tadalafil is contraindicated for patients with a known hypersensitivity to tadalafil or any component of the tablet.

Additional information about Cialis

Cialis Indication: Used for the treatment of erectile dysfunction
Mechanism Of Action: Cialis inhibits the cGMP specific phosphodiesterase type 5 (PDE5) which is responsible for degradation of cGMP in the corpus cavernosum located around the penis. Penile erection during sexual stimulation is caused by increased penile blood flow resulting from the relaxation of penile arteries and corpus cavernosal smooth muscle. This response is mediated by the release of nitric oxide (NO) from nerve terminals and endothelial cells, which stimulates the synthesis of cGMP in smooth muscle cells. Cyclic GMP causes smooth muscle relaxation and increased blood flow into the corpus cavernosum. The inhibition of phosphodiesterase type 5 (PDE5) by tadalafil enhances erectile function by increasing the amount of cGMP.
Drug Interactions: Not Available
Food Interactions: Not Available
Generic Name: Tadalafil
Synonyms: CIA; ICOS 351; Tadanafil
Drug Category: Vasoconstrictor Agents; Phosphodiesterase Inhibitors
Drug Type: Small Molecule; Approved; Investigational

Other Brand Names containing Tadalafil: Cialis; Cialis/Tadalafil Hcl; Cialis/Taladafil;
Absorption: After single oral-dose administration, the maximum observed plasma concentration (Cmax) of tadalafil is achieved between 30 minutes and 6 hours (median time of 2 hours). Absolute bioavailability of tadalafil following oral dosing has not been determined.
Toxicity (Overdose): Oral, Rat LD₅₀ = 2000 mg/kg, no deaths or toxicity.
Protein Binding: 94%
Biotransformation: Tadalafil is predominantly metabolized by CYP3A4 to a catechol metabolite. The catechol metabolite undergoes extensive methylation and glucuronidation to form the methylcatechol and methylcatechol glucuronide conjugate, respectively. In vitro data suggests the metabolites are not expected to be pharmacologically active at observed metabolite concentrations.
Half Life: 17.5 hours
Dosage Forms of Cialis: Tablet Oral
Chemical IUPAC Name: (6R-trans)-6-(1,3-benzodioxol-5-yl)-2,3,6,7,12,12a-hexahydro-2-methyl-pyrazino[1',2':1,6]pyrido[3,4-b]indole-1,4-dione
Chemical Formula: C22H19N3O4
Tadalafil on Wikipedia: https://en.wikipedia.org/wiki/Tadalafil
Organisms Affected: Humans and other mammals