Is Viagra less effective than Stendra? No: if anything, the reverse. Stendra is the US brand name of avanafil, the medicine registered in Australia as Spedra, and when the trials are pooled, avanafil 100 mg works less well than sildenafil 50 mg, the medicine in Viagra, with a similar rate of side effects (Chen et al., 2015). Where avanafil differs is timing: it is taken closer to sex.
What is Stendra called in Australia?
Spedra. Avanafil is "marketed in the US under the brand name STENDRA" (Kedia et al., 2013). In Australia, Spedra 50, 100 and 200 mg tablets have been on the Australian Register of Therapeutic Goods since 6 April 2016, sponsored by A. Menarini Australia (ARTG — Spedra), and healthdirect lists avanafil (Spedra) among the erectile dysfunction (ED) medicines available here (healthdirect — ED medicines). Like Viagra, it needs a prescription (Spedra CMI).
Does avanafil work better than sildenafil?
Not in the pooled evidence. A network analysis of 82 trials with 47,626 men compared starting doses: sildenafil 50 mg had the greatest effect, while avanafil 100 mg had "similar overall adverse events" but "a markedly lower global efficacy" (Chen et al., 2015). Australian Prescriber's 2019 review of avanafil read that analysis the same way: "avanafil appears to have lower efficacy relative to sildenafil. However, avanafil has a lower frequency of adverse effects, depending on the dose", though the confidence intervals overlap (Australian Prescriber, 2019).
Did any trial find avanafil better?
One did, with drug-company employees among its authors. In a trial in India of 220 men, avanafil 100 mg did better than sildenafil 50 mg on an erection score at 8 and 12 weeks and acted sooner; two of its authors worked for Zydus Healthcare (Kumar et al., 2022). In 160 men treated after prostate cancer surgery, avanafil 200 mg and sildenafil 100 mg gave similar sexual-function scores over six months, but erection hardness scored higher on sildenafil, and side effects affected 5% of men on avanafil against 20% on sildenafil (Della Camera et al., 2020). One industry-linked trial favours avanafil; the pooled evidence does not.
So where does avanafil differ?
In timing, not strength. Spedra is taken "approximately 15 to 30 minutes before anticipated sexual activity" (Spedra CMI). Viagra is taken about one hour before sex (Viagra CMI) and usually starts working within 30 minutes to one hour (healthdirect — Sildenafil). No Spedra label states how long its effect lasts. Each is one dose a day at most, and neither may be combined with nitrates (Spedra CMI; Viagra CMI). Doses, food, grapefruit and side effects are set side by side in does Spedra work better than Viagra?
The short answer
Viagra is not less effective than Stendra. Stendra is avanafil under its US name, Spedra in Australia, and pooled trials rate it below sildenafil for effect, with similar or fewer side effects depending on the dose; its advantage is that it is taken closer to sex. Which ED medicine suits whom is answered in which erectile dysfunction drug is best?, and what to know before taking any of them is in our guide to ED tablets.
