When Viagra Doesn’t Work: A Tokyo Guide to ICI Therapy (Intracavernosal Injection)
Erectile dysfunction affects millions of men worldwide, and for many, oral medications such as sildenafil (Viagra) or tadalafil (Cialis) provide a reliable solution. But a significant number of men find that PDE5 inhibitors — the class of drugs these medications belong to — do not produce a satisfactory erection, either due to underlying vascular conditions, diabetes, prostate surgery, or other causes. If that describes your experience, you are not alone, and there are effective next-step treatments available in Tokyo.
This guide explains intracavernosal injection (ICI) therapy: what it is, how it works, what results look like in practice, how much it costs, and who is a suitable candidate — all in plain English, tailored for expatriates and international visitors seeking care in Japan.
What you’ll learn in this article:
- What ICI therapy (Trimix/Bimix self-injection) is and how it differs from oral ED medication
- Why oral PDE5 inhibitors fail for some men — and what to do next
- What a realistic ICI treatment programme looks like, step by step
- Cost ranges for ICI therapy in Tokyo
- Who is a good candidate and who should approach with caution
Have a question about this treatment?
Message us on LINE or WhatsApp — our English-speaking team usually replies the same day.
What Is ICI Therapy and Why Is It Used?
Intracavernosal injection (ICI) therapy involves injecting a small amount of vasoactive medication directly into the side of the penis — specifically into the corpus cavernosum, the spongy tissue that fills with blood during an erection. By acting locally on the blood vessels and smooth muscle tissue, the medication can produce a firm erection regardless of whether the normal nerve or hormonal signals are functioning properly.
The most commonly used formulations are known as Trimix (a combination of alprostadil, phentolamine, and papaverine) and Bimix (papaverine with phentolamine). These compounds work by relaxing smooth muscle and dilating blood vessels in the penile tissue, allowing blood to flow in and produce an erection. The injection is performed by the patient himself at home, using a very fine needle, after receiving thorough training from a physician.
ICI therapy is not considered a first-line treatment — it is typically recommended when oral PDE5 inhibitors (sildenafil, tadalafil, vardenafil) have been tried at adequate doses and have not produced satisfactory results.
Why Do Oral ED Medications Fail for Some Men?
PDE5 inhibitors work by enhancing the body’s natural response to sexual stimulation. They require an intact nitric oxide signalling pathway — meaning the nerves and blood vessels need to be at least partially functional. For men whose ED stems from severe arterial disease, radical prostatectomy (surgical prostate removal), spinal cord injury, or poorly controlled diabetes with nerve damage, this pathway may be significantly compromised.
Studies suggest that oral PDE5 inhibitors fail to produce an adequate response in approximately 30–35% of men with ED, with non-response rates rising above 50% in men who have undergone nerve-sparing radical prostatectomy (Montorsi et al., 2005). In these cases, ICI therapy bypasses the need for intact nerve signalling entirely, acting directly on the target tissue.
Other reasons oral medications may be unsatisfactory include drug interactions, cardiovascular contraindications, or simply inadequate rigidity at the prescribed dose.
ICI vs. Oral Therapy: A Comparison
| Feature | Oral PDE5 Inhibitors (Viagra/Cialis) | ICI Therapy (Trimix/Bimix) |
|---|---|---|
| Route of administration | Oral (tablet) | Self-injection into penile tissue |
| Requires sexual stimulation | Yes | No (erection occurs with or without arousal) |
| Onset of action | 30–60 minutes | 5–20 minutes |
| Efficacy in PDE5 non-responders | Limited | High (up to 80–90% success in selected patients) |
| Suitable after prostatectomy | Partially (nerve-dependent) | Yes (nerve-independent mechanism) |
| Systemic side effects | Headache, flushing, nasal congestion | Minimal systemic effects; localised risks (see below) |
| Patient training required | No | Yes — in-clinic injection training session |
| Prescription required in Japan | Yes | Yes |
What to Expect: Before, During and After ICI Therapy
Initial Consultation and Prescribing
The process begins with a thorough medical consultation. The physician will review your ED history, current medications, cardiovascular status, and prior response to oral therapy. Blood tests and a brief physical assessment may be requested before a prescription is issued.
At BIOTOPE CLINIC in Shirokanedai, Dr. Karibe’s men’s health consultations are conducted in English, which is particularly important for this type of sensitive discussion. The initial consultation fee is ¥3,300, and a surgical or specialist consultation with Dr. Karibe is ¥2,200.
In-Clinic Training Session
Before self-injecting at home, patients receive hands-on instruction from clinical staff. You will learn the correct injection site (typically the lateral aspect of the penile shaft, avoiding the urethra and dorsal vessels), the proper technique for drawing up the medication, and how to recognise and respond to the main side effect of concern — prolonged erection (priapism).
The starting dose is always conservative, and dose titration is performed under medical supervision over subsequent visits until the optimal response is achieved.
Ongoing Home Use
Once trained and at a calibrated dose, most men are able to self-administer the injection at home prior to sexual activity. The medication is typically prepared as a compounded formulation (mixed by a pharmacy under physician prescription). Injections are generally recommended no more frequently than once every 24 hours and no more than three times per week.
Dr. Karibe’s Note
Many of our international patients are relieved to find that the injection itself is far less daunting in practice than it sounds. The needle used is extremely fine — similar to an insulin needle — and most men report minimal discomfort after the first one or two administrations. The most important thing at the training stage is understanding the warning signs of prolonged erection, which is a medical situation that requires prompt attention if an erection persists beyond four hours. We ensure every patient leaves the clinic with clear, written guidance in English on what to do in that event.
Expected Results and Efficacy
Clinical reports indicate that ICI therapy produces a satisfactory erection in approximately 80–90% of men who have not responded to oral PDE5 inhibitors, including those with post-prostatectomy ED and severe vasculogenic (vascular-origin) dysfunction (Hatzimouratidis et al., 2016). The erection typically begins within 5–20 minutes of injection and lasts for a duration that is dose-dependent — usually 30–60 minutes when correctly calibrated.
Importantly, results are highly dependent on correct dosing. Underdosing produces an inadequate erection; overdosing raises the risk of priapism. This is why supervised dose titration during the early phase of treatment is clinically essential, not optional.
Long-term satisfaction rates in studies tend to be somewhat lower than initial efficacy rates, primarily due to the practical demands of self-injection. Patient education and ongoing physician support significantly improve adherence.
Common Misconceptions About ICI Therapy
Misconception 1: “ICI is a last resort only for very severe cases”
While ICI therapy is indeed a second- or third-line treatment in clinical guidelines, it should not be perceived as an extreme measure reserved only for the most severe ED. For men with specific causes of ED — such as post-surgical nerve disruption or significant arterial disease — ICI may actually be the most appropriate and effective option, even earlier in the treatment pathway. A physician’s recommendation for ICI does not imply that the condition is untreatable by other means; it means that ICI is particularly well-matched to the underlying cause.
Misconception 2: “Once you start injections, you become dependent on them permanently”
This is a common concern but not entirely accurate. Some men use ICI therapy as a bridge — for example, in the months following prostatectomy — while natural erectile function gradually recovers. Clinical reports suggest that regular penile oxygenation through ICI-induced erections may, in some post-surgical cases, support tissue health and improve the chances of recovering spontaneous function over time. Whether ICI is temporary or long-term depends entirely on the individual’s underlying condition and response to treatment.
Cost of ICI Therapy in Tokyo
ICI therapy costs in Tokyo vary depending on the clinic, the formulation prescribed, the number of training sessions required, and the frequency of follow-up. The following is a general guide for English-speaking patients considering treatment at BIOTOPE CLINIC.
- Initial consultation: ¥3,300 (general) or ¥2,200 (specialist consultation with Dr. Karibe)
- ED medication (oral PDE5 inhibitors, if prescribed): Sildenafil and tadalafil are available by prescription; pricing varies by dosage and quantity
- ICI formulation (Trimix/Bimix): Compounded medication costs vary depending on the prescription volume and pharmacy. Discuss specifics during your consultation.
- Training and follow-up visits: Priced individually; your consultation will include a clear breakdown
- Pre-treatment blood work (where indicated): ¥11,000
For men who may also benefit from complementary approaches — such as nutritional IV therapy or NMN supplementation as part of a broader men’s health programme — these are available at BIOTOPE CLINIC and can be discussed alongside ED treatment during a consultation with Dr. Karibe.
For an accurate quote, we recommend booking a consultation.
Have a question about this treatment?
Message us on LINE or WhatsApp — our English-speaking team usually replies the same day.
Who Is a Good Candidate for ICI Therapy?
Suitable Candidates
- Men with ED who have not responded to oral PDE5 inhibitors at adequate doses
- Men with post-radical prostatectomy ED (with or without nerve sparing)
- Men with severe vasculogenic ED (arterial insufficiency or venous leakage)
- Men with ED related to spinal cord injury or neurological conditions
- Men who cannot take oral PDE5 inhibitors due to cardiovascular medication interactions (e.g., nitrate medications)
- Men who are comfortable with self-injection and committed to a structured training and follow-up programme
Who Should Approach with Caution or Avoid ICI
- Men with bleeding disorders or on anticoagulant therapy (requires medical review)
- Men with a history of priapism (prolonged erection) or sickle cell disease
- Men with significant penile anatomical abnormalities (Peyronie’s disease — requires individual assessment)
- Men who are unwilling or unable to self-inject or attend training sessions
- Men with severe needle phobia or dexterity limitations
In Dr. Karibe’s clinical experience at BIOTOPE CLINIC, candidacy assessment is always individualised. A thorough consultation will determine whether ICI therapy is appropriate, whether a combination approach with oral therapy is preferable, or whether other men’s health interventions should be considered first.
Where to Get ICI Therapy in Tokyo (English Consultations)
Within our clinic group, English-speaking consultations are handled at BIOTOPE CLINIC in Shirokanedai (Minato-ku, Tokyo) by Dr. Jun Karibe. Our sister clinic, Kojimachi Dermatology & Plastic Surgery Clinic in Ichigaya, handles Japanese-language insurance dermatology. Bookings and enquiries in English: LINE or WhatsApp.
BIOTOPE CLINIC’s men’s health service covers the full spectrum of ED care in English — from oral PDE5 inhibitor prescriptions through to ICI therapy training, dose titration, and ongoing management. All consultations are private and conducted with complete confidentiality.
Frequently Asked Questions
- Q. Is ICI therapy legal and available in Japan?
- Yes. Intracavernosal injection therapy can be prescribed by licensed physicians in Japan as a compounded medication formulation for patients who do not respond to oral ED treatments. It is not available over the counter and requires a prescription from a qualified doctor following a proper medical evaluation.
- Q. Does the injection hurt?
- Most men find the injection less painful than expected. The needle used is very fine — comparable to those used for insulin injections in diabetes management. Mild discomfort or a brief stinging sensation at the injection site is possible, but significant pain is uncommon with correct technique. Clinical training helps patients learn to administer the injection safely and with minimal discomfort.
- Q. What is priapism and what should I do if it happens?
- Priapism is a prolonged erection lasting more than four hours that is not related to sexual stimulation. It is the most serious potential side effect of ICI therapy and requires prompt medical attention, as prolonged ischaemic priapism can cause permanent tissue damage. Patients are given clear emergency guidance before beginning home self-injection, and dose titration under medical supervision is specifically designed to minimise this risk.
- Q. Can ICI therapy be used alongside oral ED medication?
- In some cases, a combination approach is appropriate, but this must be determined by a physician. Using ICI alongside oral PDE5 inhibitors without medical guidance significantly increases the risk of priapism. Any combination strategy should be supervised and dose-adjusted professionally.
- Q. How quickly can I start treatment after a first consultation?
- This depends on individual circumstances, including whether pre-treatment blood tests are required. In straightforward cases where the medical history is clear and no additional testing is needed, treatment initiation and a training session may be arranged within a short timeframe. Your consulting physician will outline the expected timeline during the initial appointment.
Have a question about this treatment?
Message us on LINE or WhatsApp — our English-speaking team usually replies the same day.
Summary
Intracavernosal injection (ICI) therapy is a well-established, clinically proven option for men with erectile dysfunction who do not respond adequately to oral PDE5 inhibitors such as sildenafil or tadalafil. By delivering vasoactive medication directly to the penile tissue, ICI bypasses the nerve-dependent pathway that oral medications rely upon — making it particularly valuable for men with post-surgical, neurological, or severe vascular causes of ED.
Clinical evidence suggests efficacy rates of up to 80–90% in selected non-responders to oral therapy. As with any medical treatment, outcomes are individual and depend on correct candidacy assessment, supervised dose titration, and proper patient training. ICI is not without risks — principally priapism — but with physician-supervised training and clear emergency guidance, most men are able to manage the treatment safely and effectively at home.
If you have questions about ICI therapy or erectile dysfunction treatment in Tokyo, English-speaking consultations are handled at BIOTOPE CLINIC in Shirokanedai (Minato-ku, Tokyo) by Dr. Jun Karibe. Our sister clinic, Kojimachi Dermatology & Plastic Surgery Clinic in Ichigaya (Chiyoda-ku), handles Japanese-language insurance dermatology. English enquiries: LINE or WhatsApp.
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Book a Consultation or Treatment
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References
- Montorsi F, Salonia A, Zanoni M, et al. Current status of local penile therapy. International Journal of Impotence Research. 2002;14(Suppl 1):S70–S81.
- Hatzimouratidis K, Salonia A, Adaikan G, et al. Pharmacotherapy for erectile dysfunction: Recommendations from the Fourth International Consultation for Sexual Medicine. Journal of Sexual Medicine. 2016;13(4):465–488.
- Perimenis P, Markou S, Gyftopoulos K, et al. Efficacy of apomorphine and intracavernosal injections in the treatment of erectile dysfunction in patients refractory to sildenafil. European Urology. 2004;46(2):247–252.
- Bella AJ, Brant WO, Lue TF, et al. Non-arteritic anterior ischemic optic neuropathy (NAION) and phosphodiesterase type-5 inhibitors. Canadian Urological Association Journal. 2006;1(2):123–125.
- Shamloul R, Ghanem H. Erectile dysfunction. The Lancet. 2013;381(9861):153–165.
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