What must you never take with Viagra or Cialis?

Nitrates, in any form, and amyl nitrite ("poppers"). Nitrates are angina and heart medicines — glyceryl trinitrate (nitroglycerin), isosorbide mononitrate and dinitrate, nicorandil and sodium nitroprusside — as tablets, patches, sprays or injections (Viagra consumer medicine information). With sildenafil they can cause "a sudden drop in your blood pressure that is hard to treat" (healthdirect), and the ban covers every ED tablet of this class, tadalafil included (healthdirect). It also covers riociguat, a medicine for high blood pressure in the lungs (sildenafil label). With tadalafil the interaction outlasts a day: in a study it was still present after 24 hours and gone by 48 (tadalafil label). The detail: can nitrates be taken with Viagra? and what happens when nitroglycerin meets sildenafil.

Beyond nitrates the labels name a short list, taken class by class below. The Viagra leaflet warns that with some of them you "may need different amounts of your medicine", so give the GP who prescribes your ED tablet the full list of what you take, including vitamins, supplements and anything bought without a prescription. The lists in full: what drugs interact with Viagra?, which medications should not be taken with sildenafil, taking Viagra alongside other medicines and Cialis interactions with medicines and supplements.

Can you take Viagra with antibiotics like amoxicillin?

It depends on the antibiotic, and amoxicillin is not one the labels name. Neither the Australian Viagra leaflet nor the sildenafil and tadalafil labels list amoxicillin. The ones they do name slow CYP3A4, the enzyme that breaks both medicines down: erythromycin raised sildenafil exposure by 182% in a study, and clarithromycin is expected to raise tadalafil levels, while azithromycin had no effect on sildenafil. With such a medicine, a 25 mg sildenafil starting dose should be considered (sildenafil and tadalafil labels). The most-asked pairing: can you take amoxicillin with Viagra?; the class: Viagra with antibiotics.

Antifungals and HIV medicines raise the level more. Ketoconazole and itraconazole are stronger inhibitors of the same enzyme. The HIV medicine ritonavir raised sildenafil exposure elevenfold: the pair is not advised, and sildenafil should never exceed 25 mg in 48 hours alongside it; ketoconazole doubled to quadrupled tadalafil exposure, depending on the dose (sildenafil and tadalafil labels).

Can you take Viagra or Cialis with blood thinners like Xarelto?

The labels found no interaction with warfarin or aspirin, and neither names Xarelto. Sildenafil had no significant interaction with warfarin, and neither medicine added to aspirin's effect on bleeding time or tadalafil to warfarin's effect on clotting (sildenafil and tadalafil labels). Xarelto is rivaroxaban, an anticoagulant (Xarelto consumer medicine information). What the sildenafil label does flag is bleeding problems: with no safety data in bleeding disorders or an active stomach ulcer, it is used there only after weighing benefit and risk. The drawn questions: can Xarelto be taken with Viagra or Cialis?, Viagra while on warfarin or another blood thinner and is aspirin OK with Viagra?

Is Cialis a blood thinner? No. Tadalafil is a PDE5 inhibitor, like sildenafil; blood thinners are anticoagulants such as warfarin, apixaban and rivaroxaban, and antiplatelet medicines such as aspirin and clopidogrel (healthdirect). Whether aspirin helps erections is a separate question: can aspirin help erectile dysfunction?

Can you take Viagra with amlodipine and other blood-pressure medicines?

Usually, with care: the two lower blood pressure together. healthdirect lists blood pressure medicines among sildenafil's interactions. In the label's study, sildenafil added to amlodipine lowered lying-down blood pressure by a further 8/7 mmHg — about what sildenafil does on its own — and across the main blood-pressure classes, side effects were no different from placebo. Tadalafil had no clinically significant interaction with amlodipine, enalapril, metoprolol, a thiazide or the sartans tested, though starting it daily may call for a change in the blood-pressure dose (sildenafil and tadalafil labels). See can Viagra be taken with amlodipine?, Viagra with high blood pressure medication and which ED medicines suit men with high blood pressure. The names give the class away: ACE inhibitors often end in "-pril", sartans in "-sartan", many calcium channel blockers in "-pine" and beta-blockers in "-lol" (healthdirect).

If your blood pressure is already low, sildenafil is not for you: the label rules it out below 90/50 mmHg, and the Australian leaflet if blood pressure "is unusually high or low or is not effectively treated" — can you take Viagra with low blood pressure?

Can you take Viagra with tamsulosin or alfuzosin?

Yes, with care — alpha-blockers, used for high blood pressure or prostate problems, are the blood-pressure medicines the labels single out. With sildenafil they may cause symptomatic low blood pressure "in a few susceptible individuals", mostly within 4 hours, so be stable on the alpha-blocker first and consider a 25 mg starting dose; with doxazosin, some men had dizziness on standing, but no fainting was reported. Tadalafil is not recommended with doxazosin; with alfuzosin or tamsulosin these effects were not seen in a few healthy volunteers, but any alpha-blocker calls for caution and the lowest starting dose, notably in older men (sildenafil and tadalafil labels). The two drawn questions: can alfuzosin and sildenafil be taken together? and Viagra with tamsulosin (Flomax).

Can you take Viagra with dapoxetine (Priligy)?

The Australian product information says no. Dapoxetine (Priligy), a prescription medicine for premature ejaculation (TGA), "should not be used in men with erectile dysfunction (ED) who are using PDE5 inhibitors" — the class of Viagra and Cialis — because the pair may lower blood pressure on standing; the combination's safety and effectiveness "have not been established". Priligy can itself make you faint and "is not intended for continuous daily use" (Priligy product and consumer medicine information). The three drawn questions: can sildenafil and dapoxetine be taken together?, Viagra and Priligy at the same time and dapoxetine with sildenafil every day. Lasting longer is its own guide: how to last longer in bed.

Can you take Viagra with antidepressants or anxiety medicines?

The sildenafil label found that common antidepressants do not change its levels: SSRIs and tricyclic antidepressants had no effect on how the body handles it. Sertraline (Zoloft) is an SSRI (Zoloft consumer medicine information) — can you take Viagra with sertraline? Venlafaxine and alprazolam (Xanax) are not named in the sildenafil or tadalafil labels; what is known is in sildenafil and venlafaxine together, can Xanax and Viagra be taken together? and Xanax with Cialis.

The antidepressant can also be the cause. The Zoloft leaflet lists impaired sexual function in men among its side effects, sometimes continuing after stopping. How sildenafil sits alongside an antidepressant: Viagra with antidepressants and anxiety medication; whether sertraline can cause lasting problems: can Zoloft cause permanent ED?

Can you drink alcohol, coffee or grapefruit juice with Viagra or Cialis?

Alcohol: carefully, and not much before sex. The Viagra leaflet says alcohol "can temporarily impair the ability to get an erection" and not to drink large amounts before sex; in the label's study, sildenafil did not add to alcohol's effect on blood pressure at a mean peak blood alcohol of 80 mg/dL. Cialis can be taken with or without alcohol, but with large amounts some men feel dizzy (Cialis consumer medicine information). See can you drink alcohol with Viagra? and drinking while taking Cialis or tadalafil.

Grapefruit juice raises the level; caffeine is not named. Grapefruit juice "may give rise to modest increases in plasma levels of sildenafil" (sildenafil label), and the Cialis leaflet lists it too: does grapefruit juice boost Viagra? Neither label mentions caffeine or energy drinks: coffee and caffeine with sildenafil and can you mix energy drinks with Viagra?

Can you take painkillers with Viagra or Cialis?

Of the everyday painkillers only aspirin appears in the labels, and neither medicine added to its effect on bleeding. Ibuprofen, paracetamol and tramadol are not among the interacting medicines in the sildenafil or tadalafil labels or the Australian leaflets. Headache is a common side effect of ED medicines (healthdirect), which is why the question comes up: can ibuprofen be taken with Cialis?, ibuprofen and Viagra, Tylenol (paracetamol) with Viagra or Cialis and tramadol with Viagra. Whether regular ibuprofen affects erections is another matter: can ibuprofen cause or help ED?

Can you take two ED medicines together, or more than one tablet?

No. Sildenafil with another PDE5 inhibitor or any other erectile dysfunction treatment has not been studied, "therefore the use of such combinations is not recommended" (sildenafil label); the tadalafil label and the vardenafil leaflet say the same. That answers can you mix Viagra and Cialis?, Viagra and Levitra together and Viagra with Trimix. It covers doubling up too: no more than one sildenafil tablet in 24 hours (healthdirect), and if too much has been taken, phone the Poisons Information Centre on 13 11 26 (Viagra consumer medicine information) — is it safe to take more than one Viagra?

What about statins, metformin, finasteride, testosterone and supplements?

One question is about detection, not interaction: does Viagra show up in drug tests?

Can you take Viagra after a heart attack, with atrial fibrillation or with glaucoma?

Not within six months of a heart attack or stroke, says the Australian Viagra leaflet, nor if heart or blood-vessel problems make sex inadvisable. Tadalafil is ruled out in uncontrolled heart-rhythm problems, and atrial fibrillation is among the heart side effects reported with sildenafil (sildenafil and tadalafil labels); if you also take a blood thinner, see above. Details: Viagra after a heart attack or with heart medicines and Viagra with atrial fibrillation.

Glaucoma is not among the reasons not to take sildenafil — the eye conditions that are include vision loss from NAION and inherited retinal disease such as retinitis pigmentosa — though it does appear among the eye side effects reported with it (sildenafil label): can Viagra be taken with glaucoma?

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