Cialis (Tadalafil) Withdrawal and Discontinuation Syndrome: What to Expect When You Stop

Does stopping Cialis cause withdrawal?

The Cialis prescribing information describes no withdrawal syndrome, and its dosing sections give starting doses and dose adjustments rather than a schedule for stopping [1]. The tadalafil trials on this page report outcomes during treatment [2][3][4].

Tadalafil is a PDE5 inhibitor. During sexual stimulation, nitric oxide raises cyclic GMP in penile smooth muscle, relaxing it and increasing blood flow, and tadalafil slows the breakdown of that cyclic GMP; the drug has no effect without sexual stimulation [1]. The benefit the label describes is on-treatment and time-limited: improved erectile function compared with placebo for up to 36 hours after a dose [1].

What the trials measured

Erectile function. In five 12-week trials, 1,112 men with mild to severe ED were randomized to placebo or tadalafil 2.5, 5, 10 or 20 mg as needed [2]. With 20 mg, the erectile function domain of the International Index of Erectile Function improved by a mean 7.9 points, 75% of intercourse attempts were successful, and 81% reported improved erections versus 35% on placebo [2].

Urinary symptoms. In a 12-week trial, 161 men took tadalafil 5 mg once daily and 164 took placebo. Total International Prostate Symptom Score fell 5.6 points with tadalafil versus 3.6 with placebo; improvement was apparent after one week and significant by week four [3]. Peak urine flow and post-void residual volume did not improve significantly [3].

These are on-treatment results, not measurements of symptoms after stopping. As tadalafil clears, the ED or BPH symptoms it was treating may return.

How long tadalafil stays in the body

Tadalafil has a mean terminal half-life of 17.5 hours in healthy subjects, with oral clearance of about 2.5 L/h and excretion of about 61% in feces and 36% in urine as metabolites [1]. Blood levels therefore fall by roughly half every 17 to 18 hours after the last dose.

With once-daily dosing, steady state is reached within 5 days, and exposure at steady state is about 1.6-fold that of a single dose [1].

Is there a taper schedule for stopping Cialis?

The label gives none. Its dosing sections cover the starting dose and how to move it up or down during treatment, not how to come off [1].

The label does include one time limit. When Cialis is used with finasteride to start BPH treatment, use is recommended for up to 26 weeks, because the incremental benefit of Cialis falls between week 4 and week 26 and the benefit beyond 26 weeks is unknown [1]. That is a limit on combined treatment, not a step-down schedule.

Nitrates after the last dose

Nitrates must not be combined with Cialis. Any form of organic nitrate, used regularly or intermittently, is contraindicated with Cialis, as are guanylate cyclase stimulators such as riociguat [1]. In a crossover study, 150 men took tadalafil 20 mg or placebo daily for 7 days and then received sublingual nitroglycerin 0.4 mg at set times; standing systolic blood pressure fell below 85 mm Hg in more men on tadalafil at 4, 8 and 24 hours (P<0.05), with no difference at 48, 72 and 96 hours [7].

For a life-threatening situation in which a nitrate is medically necessary, the label says at least 48 hours should have elapsed after the last Cialis dose before nitrate administration is considered, and then only under close medical supervision with hemodynamic monitoring [1]. That is an emergency provision, not a spacing rule for routine nitrate use.

Side effects reported during Cialis treatment

These are effects reported during treatment, not withdrawal effects. In the as-needed ED trials, headache was reported by 5% of men on placebo versus 15% on tadalafil 20 mg, dyspepsia by 1% versus 10%, back pain by 3% versus 6%, myalgia by 1% versus 3%, nasal congestion by 1% versus 3% and flushing by 1% versus 3% [1]. Discontinuation for adverse events was 3.1% on tadalafil 10 or 20 mg versus 1.4% on placebo; for once-daily ED dosing it was 4.1% versus 2.8%, and in the BPH and ED/BPH studies 3.6% versus 1.6% [1].

Back pain and myalgia during treatment generally began 12 to 24 hours after a dose and typically resolved within 48 hours [1]. The label's warnings about sudden vision loss and sudden hearing loss also concern events reported during treatment, not withdrawal [1].

Pulmonary arterial hypertension is a different product

Adcirca is a separate tadalafil product, 20 mg tablets, approved for pulmonary arterial hypertension [5]. Both Adcirca and Cialis come as 20 mg tablets [9][5]. The Cialis label says combinations with other PDE5 inhibitors or other ED treatments have not been studied [1]. This page covers Cialis for ED and BPH.