By the Medsmingle Team · Updated 13 November 2026

This is a prescription medicine. Only take it if it has been prescribed for you after a medical assessment, and follow your doctor’s and pharmacist’s instructions.

Sildenafil was the first oral medicine approved for erectile dysfunction (ED), launched as Viagra in 1998. Today it’s available as low-cost generics and remains one of the most widely prescribed ED treatments. Response varies, and ED associated with diabetes or surgery may need specialist treatment.

How sildenafil works

An erection depends on blood flowing into the penis when you’re sexually aroused. Sildenafil belongs to a group called PDE5 inhibitors. It blocks the enzyme PDE5, which normally ends an erection, so blood vessels in the penis relax and fill more easily. It doesn’t cause an erection on its own: you still need sexual stimulation, and it doesn’t increase desire.

How fast it works and how long it lasts

• Usually starts working in 30 to 60 minutes
• Effects last about 4 to 6 hours (this is the window in which an erection is easier, not a 4-hour erection)
• A heavy or high-fat meal can delay it by up to an hour; it works fastest on an empty or light stomach

Typical dosing

For ED, the usual starting dose is 50 mg, taken about 1 hour before sex, no more than once a day. Depending on effect and side effects, a doctor may adjust it to 25 mg or 100 mg (the maximum). Lower starting doses are used for men over 65, those with liver or severe kidney problems, and those taking certain other medicines. Under the brand name Revatio, sildenafil is also prescribed at different doses for pulmonary arterial hypertension.

If it doesn’t seem to work

• If it is not helping, ask your prescriber to review timing, health conditions and the prescribed dose; do not increase it yourself.
• Take it at the right time and allow for sexual stimulation
• Avoid a heavy meal and too much alcohol beforehand
• Talk to your doctor about adjusting the dose or trying another option

Common side effects

• Headache and flushing (the most common)
• Indigestion or heartburn
• Stuffy or runny nose
• Dizziness
• Temporary changes in vision: a blue tinge, blurred vision or light sensitivity
• Back or muscle aches

These are usually mild and fade within a few hours.

Who must avoid it or needs specialist assessment

• Anyone taking nitrates (nitroglycerin, isosorbide mononitrate or dinitrate) or recreational “poppers” (amyl nitrite): the combination can cause a dangerous drop in blood pressure
• Anyone taking riociguat (Adempas) for pulmonary hypertension
• Do not use if your clinician says sexual activity is unsafe. A recent heart attack or stroke requires individual specialist assessment.
• Very low blood pressure, severe liver disease or inherited eye conditions require assessment before treatment; suitability differs between medicines.

Get emergency help (call 911) if you have

• Chest pain, fainting or severe dizziness during or after sex: tell the medical team you took an ED medicine, including the exact medicine and when you last took it
• An erection lasting more than 4 hours (priapism), which can permanently damage the penis
• Sudden loss or decrease of vision in one or both eyes
• Sudden decrease or loss of hearing, with or without ringing or dizziness
• Swelling of the face, lips or throat, or trouble breathing

Important interactions

• Alpha-blockers (tamsulosin, doxazosin): risk of low blood pressure; your doctor will space doses or start low
• Some antibiotics and antifungals (clarithromycin, erythromycin, ketoconazole, itraconazole) and HIV medicines (ritonavir): raise sildenafil levels
• Other ED medicines: don’t combine
• Alcohol: heavy drinking can worsen ED and increase dizziness
• Grapefruit juice in large amounts may raise levels slightly

ED can be an early warning sign

ED often shares causes with heart disease, diabetes and high blood pressure, and it can appear years before heart problems. A proper check-up, including blood pressure, blood sugar and cholesterol, is an important part of treatment. Stopping smoking, regular exercise, losing excess weight and cutting back on alcohol can all improve erections.

Generic vs brand

FDA-approved generic sildenafil contains the same active ingredient as Viagra and must meet the same quality standards. Be wary of unregulated products sold online without a prescription, which may contain the wrong dose or hidden ingredients.

Frequently asked questions

Can I take sildenafil every day?

It’s taken as needed, no more than once in 24 hours. Daily low-dose treatment is usually done with tadalafil instead; see sildenafil vs tadalafil.

Does sildenafil make you last longer?

It isn’t designed to treat premature ejaculation, though some men find it easier to maintain an erection.

Is sildenafil safe for the heart?

Suitability depends on your heart health and medicines. A prescriber must assess you; never combine it with nitrates.

Can women take sildenafil?

It isn’t approved for sexual problems in women.

For questions about a prescription or symptoms, speak with your own doctor or pharmacist. For website enquiries, contact our team.

General information only. It isn’t a substitute for advice from your doctor or pharmacist.

Source and further reading

MedlinePlus patient medicine information. This overview does not list every warning or interaction.

By the Medsmingle Team · Updated 13 November 2026

This is a prescription medicine. Only take it if it has been prescribed for you, and follow your doctor’s and pharmacist’s instructions.

Tamsulosin (Flomax) is an alpha-blocker used to ease urinary symptoms of an enlarged prostate (BPH), such as a weak stream and needing to go at night. Doctors sometimes also use it to help pass kidney stones. See enlarged prostate (BPH).

How it works

It relaxes the muscles in the prostate and bladder neck so urine flows more easily. It doesn’t shrink the prostate.

How to take it

• Once a day, about 30 minutes after the same meal each day
• Swallow the capsule whole
• Improvement often starts within days, with full effect in 2 to 4 weeks

Side effects

• Dizziness or light-headedness, especially when standing up or after the first doses: stand up slowly
• Changes in ejaculation or semen volume; discuss persistent or concerning symptoms with your prescriber
• Stuffy nose, headache

Important warnings

• Cataract surgery: tell your eye surgeon you take or have taken tamsulosin, as it can affect the iris during surgery
• Fainting risk is higher with other blood pressure medicines or erectile dysfunction pills; ask your doctor about timing
• A painful erection lasting more than 4 hours (very rare) needs emergency care
• Rare sulfa allergy reactions

See a doctor if

Being unable to urinate needs urgent medical assessment. Also contact a clinician for blood in the urine or worsening symptoms.

Frequently asked questions

Can I take tamsulosin at night?

Follow the timing on your prescription. If you wish to change the meal or time, ask your pharmacist first.

Does tamsulosin affect fertility?

It can reduce semen volume, which may affect conception while taking it; discuss fertility concerns with your prescriber before changing treatment.

For questions about a prescription or symptoms, speak with your own doctor or pharmacist. For website enquiries, contact our team.

This article is for general information only and isn’t a substitute for advice from a doctor or pharmacist.

Source and further reading

MedlinePlus patient medicine information. This overview does not list every warning or interaction.

By the Medsmingle Team · Updated 13 November 2026

This is a prescription medicine. Only take it if it has been prescribed for you, and follow your doctor’s and pharmacist’s instructions.

Finasteride (Propecia 1 mg) is a daily tablet for male pattern hair loss. Along with minoxidil, it’s one of the two treatments with the strongest evidence. See also hair loss treatment for men.

How it works

It blocks the enzyme that turns testosterone into DHT, the hormone that shrinks hair follicles in men with pattern hair loss.

What results to expect

• Most men stop losing more hair, and many see some regrowth, especially at the crown
• Give it at least 6 to 12 months before judging
• Benefits fade over about a year if you stop

Side effects

• Lower libido, erection problems or less ejaculate in a small percentage of men (about 1 to 2% more than placebo in trials). Sexual symptoms may resolve, but persistent symptoms after stopping have also been reported.
• Breast tenderness or enlargement (rare)
• Mood changes, including depression, have been reported. For hair-loss treatment, stop and contact your doctor promptly if depression or suicidal thoughts develop; seek emergency help for immediate danger.

A small number of men report side effects that continue after stopping (sometimes called post-finasteride syndrome); this is still being studied.

Important to know

• Women who are or may become pregnant must not handle crushed or broken tablets, as finasteride can harm a male baby
• It can lower PSA levels; tell your doctor before prostate screening so results are interpreted correctly.
• Don’t donate blood while taking it and for 1 month after

Frequently asked questions

Can women take finasteride for hair loss?

It isn’t approved for women and must not be used in pregnancy. Some doctors prescribe it for women after menopause.

Is it better with minoxidil?

Many dermatologists recommend using both, as they work in different ways.

More in our Hair Loss guide: all our articles and products on this topic in one place.

For questions about a prescription or symptoms, speak with your own doctor or pharmacist. For website enquiries, contact our team.

This article is for general information only and isn’t a substitute for advice from a doctor or pharmacist.

Source and further reading

MedlinePlus patient medicine information. This overview does not list every warning or interaction.

By the Medsmingle Team · Updated 13 November 2026

This is a prescription medicine. Only take it if it has been prescribed for you, and follow your doctor’s and pharmacist’s instructions.

Amoxicillin and Augmentin are related penicillin antibiotics. Augmentin is amoxicillin combined with clavulanic acid, which stops some bacteria from breaking the antibiotic down.

The difference

• Amoxicillin treats many common infections: strep throat, ear infections, some sinus and chest infections, and some urinary infections.
• Augmentin covers extra bacteria that resist amoxicillin alone, so it’s often used for bites, more stubborn sinus or ear infections and some skin infections.

Your doctor chooses based on the likely bacteria. A broader antibiotic isn’t automatically better; using the narrowest effective one helps prevent resistance.

Side effects

• Diarrhea, nausea or upset stomach, more common with Augmentin
• Yeast infections (thrush)
• Rash

Taking Augmentin with food reduces stomach upset.

Penicillin allergy: get urgent help

Stop and call 911 for swelling of the face or throat, trouble breathing, or hives with dizziness. Tell your doctor about any previous reaction to penicillin. Many people labeled allergic aren’t, and an allergist can test this.

Call your doctor if you have

• Severe or watery diarrhea, especially with blood or cramps, during or after the course (possible C. diff infection)
• A blistering or peeling rash
• Yellow skin or eyes
• No improvement after 2 to 3 days

Tips

• Finish the course as prescribed unless your doctor tells you otherwise
• Never share antibiotics or use leftovers
• Antibiotics do not treat colds or flu

Frequently asked questions

Is Augmentin stronger than amoxicillin?

It works against more types of bacteria, but that doesn’t make it the better choice for every infection.

Can I drink alcohol with amoxicillin?

Ask your pharmacist about your prescription and health conditions. Alcohol may worsen side effects or make you feel more unwell.

For questions about a prescription or symptoms, speak with your own doctor or pharmacist. For website enquiries, contact our team.

This article is for general information only and isn’t a substitute for advice from a doctor or pharmacist.

Source and further reading

MedlinePlus patient medicine information. This overview does not list every warning or interaction.

By the Medsmingle Team · Updated 13 November 2026

This is a prescription medicine. Only take it if it has been prescribed for you, and follow your doctor’s and pharmacist’s instructions.

Prednisone is a corticosteroid that calms inflammation and the immune system. It’s used for asthma flare-ups, severe allergies, arthritis, skin conditions and many other illnesses, with treatment duration depending on the condition.

How to take it

• Take it in the morning with food to reduce stomach upset and trouble sleeping
• Follow the schedule exactly, especially if the dose steps down

Common short-course side effects

• Increased appetite
• Trouble sleeping, restlessness
• Mood changes: irritability, feeling “wired” or low
• Higher blood sugar, which matters if you have diabetes
• Stomach upset, heartburn

With longer use

Weeks to months of prednisone can cause weight gain, raised blood pressure, thinning bones, cataracts, easy bruising and a higher risk of infection. Your doctor will balance benefits and risks and may recommend calcium, vitamin D or bone protection.

Don’t stop suddenly after long use

The need for a taper depends on the dose, duration, repeated courses and your medical history. Follow the prescribed stopping plan, even for a short course; do not decide on a taper yourself.

Call your doctor if you have

• Signs of infection: fever, chills, sore throat
• Very high blood sugar readings, extreme thirst
• Black or bloody stools, or vomiting blood
• Severe mood changes or confusion
• Vision changes

Interactions

NSAIDs such as ibuprofen raise the risk of stomach bleeding. Tell your doctor about diabetes medicines, blood thinners and live vaccines.

Frequently asked questions

How quickly does prednisone work?

Often within hours to a day or two for inflammation and breathing problems.

Can I drink alcohol on prednisone?

It’s best to limit alcohol, which adds to stomach irritation.

For questions about a prescription or symptoms, speak with your own doctor or pharmacist. For website enquiries, contact our team.

This article is for general information only and isn’t a substitute for advice from a doctor or pharmacist.

Source and further reading

MedlinePlus patient medicine information. This overview does not list every warning or interaction.