How Does Cialis Together Work in the Body
Chemical Composition, Mechanism of Action & Metabolic Effects Explained
Key Takeaways: How Cialis Together Works
- Active Ingredient: Tadalafil 10mg, a selective PDE5 inhibitor
- Primary Action: Inhibits phosphodiesterase type 5 (PDE5) enzyme, raising cGMP levels
- Physiological Result: Relaxes penile arteries, increasing blood flow during sexual stimulation
- Onset & Duration: Works in as little as 30 minutes; effects last up to 36 hours
- Requires Arousal: Only effective with natural sexual stimulation (nitric oxide release)
- Not a daily pill: Taken as needed before sexual activity (max one per day)
Cialis Together (tadalafil) works by enhancing the body’s natural erectile response. It selectively blocks the PDE5 enzyme in penile tissues, allowing blood vessels to relax and fill with blood when you’re sexually aroused.
Important Medical Advice
If you experience an erection lasting more than 4 hours (priapism), sudden vision loss, or chest pain during sex, seek immediate medical help. Do not take Cialis Together with nitrates (e.g., GTN) or recreational poppers – this can cause a dangerous drop in blood pressure.
Chemical Composition & Molecular Structure of Cialis Together
Cialis Together tablets contain tadalafil as the active pharmaceutical ingredient, formulated for rapid absorption and selective PDE5 inhibition.
Chemical Structure Details (from PIL)
(6R,12aR)-6-(1,3-benzodioxol-5-yl)-2-methyl-2,3,6,7,12,12a-hexahydropyrazino[1',2':1,6]pyrido[3,4-b]indole-1,4-dione
Tadalafil’s unique ring structure gives it high selectivity for PDE5 and a long half‑life.
C22H19N3O4
Molar mass: 389.4 g/mol (tadalafil base). Each tablet contains 10 mg tadalafil.
Lactose monohydrate, croscarmellose sodium, hydroxypropylcellulose, etc.
Film coat: lactose, hypromellose, triacetin, titanium dioxide, iron oxide yellow, talc.
Key Pharmaceutical Properties
| Property | Value | Clinical Relevance |
|---|---|---|
| Solubility | Practically insoluble in water; slightly soluble in ethanol | Absorption enhanced by formulation; food has minimal effect |
| Protein Binding | 94% bound to plasma proteins | High binding affects distribution and drug interactions |
| Selectivity | PDE5 > PDE6, PDE11 (some affinity) | Explains rare muscle aches (PDE11) and visual disturbances at high doses |
🗒️ Pharmaceutical Insight: Tadalafil’s molecular structure differs from sildenafil, giving it a longer half‑life (17.5 hours) and duration up to 36 hours. The methylenedioxyphenyl group contributes to its high selectivity.
Mechanism of Action: How Cialis Together Creates an Erection
Cialis Together enhances the natural erection pathway by preserving cyclic GMP (cGMP) in penile tissue.
The Normal Erection Pathway
- Sexual stimulation triggers nitric oxide (NO) release from nerves in the penis.
- NO activates guanylate cyclase, an enzyme that produces cGMP from GTP.
- cGMP causes smooth muscle relaxation in penile arteries and corpora cavernosa.
- Blood flow increases, leading to an erection.
- PDE5 normally breaks down cGMP, returning the penis to flaccid state.
Where Cialis Together Intervenes
| Step | Without Cialis Together | With Cialis Together |
|---|---|---|
| NO release | Occurs only with arousal | Unaffected (still requires arousal) |
| cGMP production | Normal | Normal |
| PDE5 activity | Actively breaks down cGMP | PDE5 inhibited → cGMP accumulates |
| Blood flow & erection | Limited by cGMP breakdown | Enhanced and prolonged |
🗒️ Physiological Insight: Cialis Together does not cause an erection on its own – it amplifies the body’s natural response. Without sexual arousal (and nitric oxide), the medication has no effect.
Enzyme Inhibition: Targeting Phosphodiesterase Type 5
Tadalafil is a potent and selective inhibitor of PDE5, the enzyme responsible for degrading cGMP in the corpus cavernosum.
Inhibition Characteristics
Competitive, reversible
Binds to the catalytic site of PDE5, blocking cGMP access.
~ 1 nM
Extremely high affinity, effective at low doses.
PDE5 : PDE6 ≈ 700‑fold
Much higher selectivity than sildenafil, fewer visual side effects.
Selectivity Profile
| PDE enzyme | Tissue location | Relative inhibition | Clinical note |
|---|---|---|---|
| PDE5 | Penis, lung, vessels | Primary target | Erectile dysfunction, pulmonary hypertension |
| PDE6 | Retina | >700‑fold less | Very rare blue tinge (mainly at supra‑therapeutic doses) |
| PDE11 | Skeletal muscle, prostate | ~10‑fold less | May explain back pain / myalgia in some users |
🗒️ Biochemical Insight: Tadalafil’s high selectivity for PDE5 over PDE6 means visual disturbances are much less common than with sildenafil. The longer binding half‑life contributes to its 36‑hour efficacy window.
Metabolic Effects & Duration in the Body
Once absorbed, tadalafil is metabolised in the liver and slowly eliminated, explaining its prolonged action.
Metabolic Pathway
Primary metabolism
Liver enzyme: CYP3A4
Process: oxidation to catechol metabolites
Metabolites: mostly inactive
Half‑life
Mean: 17.5 hours
Duration: up to 36 hours
Excretion
Mainly faeces (61%) as metabolites
Urine: 36%
Timeline of Effects (10mg dose)
- 0.5 – 2 hours: Absorption, peak plasma concentration
- 2 – 12 hours: Maximal PDE5 inhibition, optimal responsiveness
- 12 – 36 hours: Declining but still effective levels
- 36 – 72 hours: Gradual elimination, negligible effect beyond 48h
🗒️ Clinical Correlation: The long half‑life gives men flexibility – they can achieve erections up to 36 hours after taking Cialis Together. However, food (especially high‑fat) does not significantly delay absorption, unlike sildenafil.
Absorption, Distribution & Elimination
Detailed pharmacokinetics from the product literature and clinical studies.
Pharmacokinetic Profile
Absorption
Oral bioavailability: Not fully determined; rapidly absorbed
Tmax: median 2h (range 0.5‑6h)
Food effect: minimal (rate slightly reduced, extent unaffected)
Distribution
Volume of distribution: 63 L
Protein binding: 94% (albumin, α1‑acid glycoprotein)
Elimination
Clearance: 2.5 L/h
Half‑life: 17.5h in healthy subjects
Special Populations
| Population | Effect on tadalafil | Dosing advice |
|---|---|---|
| Elderly (≥65) | Lower clearance (AUC ↑25%) | No adjustment needed, but caution |
| Mild‑moderate hepatic impairment | Exposure similar to healthy | Use as directed; severe impairment not studied |
| Severe renal impairment | AUC ↑100% | Maximum dose 5mg (but Cialis Together 10mg not recommended) |
| CYP3A4 inhibitors (ketoconazole) | AUC ↑300% | Limit dose to 10mg every 72h |
Clinical Efficacy for Erectile Dysfunction
Cialis Together (tadalafil 10mg) is proven effective for men with ED, including those with underlying conditions.
Efficacy Data (from PIL & studies)
| ED type / population | Success rate (10mg) | Notes |
|---|---|---|
| General ED population | ~80% improved erections | On‑demand dosing |
| Diabetes‑related ED | 60‑70% | Requires intact NO pathway |
| Post‑prostatectomy (nerve‑sparing) | ~50% | Depends on nerve preservation |
Optimal Use Based on Mechanism
- Take at least 30 minutes before sexual activity (works for up to 36h).
- Sexual stimulation is essential – tadalafil does not cause automatic erections.
- Do not use more than one tablet per day.
- Alcohol excess may temporarily impair erection – limit intake.
- Avoid grapefruit juice (inhibits CYP3A4, raises tadalafil levels).
🗒️ Prescribing Insight: Because Cialis Together lasts so long, couples can engage in sex without strict timing. However, men with cardiac risk factors should be cleared for sexual activity first.
Cialis Together Mechanism FAQs
How does Cialis Together work differently from Viagra?
Both are PDE5 inhibitors, but tadalafil (Cialis Together) has a longer half‑life (17.5h) providing up to 36 hours of effectiveness, while sildenafil lasts 4‑6 hours. Tadalafil also has higher selectivity for PDE5, causing fewer visual side effects.
Why do I need sexual stimulation for Cialis Together to work?
The drug only blocks PDE5; it does not create nitric oxide. Sexual arousal releases nitric oxide, which kick‑starts cGMP production. Without this natural trigger, there’s no cGMP to preserve, so no erection occurs.
Can Cialis Together cause back pain or muscle aches?
Yes, this is an uncommon side effect. It may be related to weak inhibition of PDE11 in skeletal muscle. The pain is usually mild to moderate and goes away on its own.
Is Cialis Together safe for men with high blood pressure?
It can be used if blood pressure is well controlled. However, tadalafil has mild vasodilator effects and may lower BP slightly. Avoid if you take nitrates or certain alpha‑blockers without doctor supervision.
What happens if I take Cialis Together every day?
Cialis Together is designed for ‘as‑needed’ use (max once daily). For daily use, a lower‑dose formulation (2.5mg or 5mg) is available, but Cialis Together 10mg is not intended for continuous daily dosing.
Need Treatment for Erectile Dysfunction?
If you're experiencing erection problems and want to know if Cialis Together is suitable, complete a confidential online consultation with a UK‑registered doctor.
Secure Prescription & Next‑Day Delivery
MHRA‑compliant | GPhC‑registered pharmacy | Discreet packaging | UK‑registered doctors
Start Cialis Together ConsultationRelated Cialis Together Guides
Medical Content Manager
Nabeel is a co-founder, and medical content manager of Chemist Doctor. He works closely with our medical team to ensure the information is accurate and up-to-date.
Medical Doctor
Dr. Feroz is a GMC-registered doctor and a medical reviewer at Chemist Doctor. He oversees acute condition and urgent care guidance.
Medical Director
Usman is a co-founder, and medical director of Chemist Doctor. He leads the organisation's strategic vision, bridging clinical and operational priorities.
Review Date: 14 February 2025
Next Review: 14 August 2025
Published on: 14 February 2025
Last Updated: 14 February 2025