This contains pholcodine which can sometimes cause constipation.
Decongestants (Lemsip, Night Nurse, Boots Cold and Flu Relief, Nurofen Cold and Flu, Benylin Day and Night)

    Decongestants can increase blood pressure or hyperactivity so should not be taken if you have high blood pressure or heart disease. Anything with an anti-histamine (eg Night Nurse) can cause drowsiness so don't drink alcohol, nor drive.
 

    Don't take aspirin on an empty stomach as it can irritate and damage the stomach lining. Aspirin can interfere with anti-coagulants and anti-inflammatory drugs so inform your pharmacist of medication you are taking. It can also trigger allergic or asthmatic reactions.
    Aspirin should never be taken by children under 12 as research has shown it may lead to a rare condition called Reyes Syndrome, a disorder that affects the liver and brain, For this reason, don't take aspirin if you're breasfeeding – it could be transferred via the breast milk.
Ibuprofen

    Always make sure you eat before taking ibuprofen as diarrhœa is common if you take it on an empty stomach.
Paracetamol

    Overdosing on paracetamol is very dangerous and can cause liver toxicity which can kill. Don't drink – alcohol stops medication working properly and strains the liver.
 

If taken short term, sleeping pills are unlikely to cause problems. However, some people may experience a dry mouth, nausea and even nervousness within four to six hours. If you take sleeping pills long term, there may be an underlying reason why you're not sleeping, so go to see your GP. Sleeping pills can interact with anti-depressants, making them stronger.
 

    These contain a non-sedating anti-histamine called loratidine. Very rarely, this can cause dry mouth, blurring of vision, constipation and impotence.
    Non sedating anti-histamines shouldn't be taken with some anti-fungal medication and certain antibiotics as they could stop these drugs working properly.
 

    These prevent the release of acid into the stomabh but they can affect the absorbtion of other medication and minerals. They decrease the absorbtion of irom and vitimin supplements.
Antacids (Rennies, Boots Indigestion Tablets, or Gaviscon, contain aluminium hydroxide, calcium carbonate, magnesium salts or sodium) – to neutralise the stomach acid.

These neutralise stomach acid, but some contain calcium carbonates which can cause constipation. And magnesium salts sometimes give you diarrhœa.
 

    These may cause diarrhœa, rashes and headaches. The main thing to remember is don't take with Valium (diazepam), epileptic and heart drugs, warfarin and the antibiotic ketoconazole. They can either stop these drugs working or increase their strength.
    GP Dr Tanvir Jamil of Burnham, Berkshire, says: "These drugs have changed peoples lives and if you can tolerate them it will make a real difference. If you get headaches within two or three days, go back to your GP. It's just a question of finding one that's right for you".
 

    Side effects can take weeks and include constipation, flatulence, headache, nausea, indigestion, abdominal pain, diarrhœa, insomnia, rash, light sensitivity, dizziness, muscle cramps, nerve pains and anæmia
    Dr Jamil says: "Many side effects occur for a few weeks and calm down. If you can bear with it, give it a few weeks and see how it goes. If the side effects interfere with your lifestyle go back to your GP. Sometimes you have to try a few different types before you get one that suits you.
 

    If you experience side-effects, don't come off the medication without medical advice. r Jamil says: "If you've been taking anti-depressants for longer than a month, you may have withdrawal symptoms if you come off them. Talk it through with your GP." Anti-depressants can cause stomach ache and nausea within 24 hours but it may take two to three weeks for other side-effects to develop. These include sweating, tremors, dry mouth, insomnia, lower sex drive and fever.
 

    Any side-effects will come on within 24 hours. You may suffer tremors, palpitations, headaches, tremors and skin problems. Rarely they can cause muscle cramps, spasms of the bronchial tubes in the lungs and low potassium levels. If they are mild, see how you feel for a few days and if the problem resolves itself. If they are severe, call you doctor immediately.
 

    These widen blood vessels, increasing blood flow to the heart. Any side-effects will usually come on within a couple of days and you may find you get headaches, rash, fatigue, nausea and dizziness. Rare side-effects include: abdominal pain, indigestion, muscle cramps, mood changes, impotence and visual disturbances. Dr Jamil says: "Occasionally your doctor will switch you from amlodipine to adalat. They are similar drugs but if you change types you may see side-effects reduce. Often it's a question of getting used to it.
 

    It's possible you'll have a tummy upset if you're on antibiotics as the medication kills friendly bacteria in the gut. This will happen within a few days. Long term use makes people prone to fungal infections. Some evidence suggests that killing friendly gut bacteria may weaken immunity.
    Dr Jamil says: "There's a great deal of choice when it comes to antibiotics. You can always find the right one that won't give you side-effects. If you have a rash, contact your doctor as this could be an allergy. Your GP will usually switch you to another type."
 

If you have side-effects it will usually happen in a couple of days. Dr Jamil says: "The first sign is upper abdominal pain. You'll have bad stomach ache and black stools which is digested blood. If this happens, come off the medication straight away and see your GP as this indicates internal bleeding." Prolonged use of NSAIDS can cause stomach ulcers. If you develop a skin rash, tell your doctor. They may also cause impaired kidney function, drowsiness, constipation, dizziness and nausea.
    There are new drugs out now called selective COX II inhibitors which cause very little stomach bleeding and are suitable for people who have had ulcers in the past or who have acidity. Dr Jamil recommends asking your doctor if these are appropriate for you. Don't take NSAIDS if you have stomach or abdominal ulcers, impaired kidney function. Avoid if you take aspirin or suffer an anti-inflammatory induced allergy such as asthma or skin rashes. Interacts with blood thinning drugs, diuretics and quinolones.
 

    Aspirin and warfarin drugs can cause gastric irritation, internal bleeding as well as asthmatic and allergic reactions. Warfarin (which is rat poison) is a blood thinning agent.
    It can cause diarrhœa, hair loss and skin rashes. These side-effects can happen in a few days. If they do, contact your doctor.
    Dr Jamil says: "Take care shaving if you are on blood thinners. If you do cut yourself, it could take five to 10 minutes to stop bleeding." Do not take if you have Hæmophilia, liver or kidney impairment, stomach ulcers, within 24 hours of surgery, while pregnant or breastfeeding because of the risk of Hæmorrhage.
    Warfarin or heparin drugs shouldn't be taken with certain anti-inflammatories, antibiotics, steriods and drugs affecting liver enzymes.
 

    Dr Jamil says: "Different pills suit different women, that's why there are so many available. Side-effects of the pill will take a few weeks as each pill is low dose. Don't stop taking the pill immediately as you may get pregnant. Have a chat with your doctor. There are lots of pills you can try."
    Side-effects include breast enlargement. fluid retention, cramps, depression, loss of libido, headaches and nausea.
    You must remember to use additional contraceptive precautions while you are taking antibiotics and for a full week after. If you're not absorbing the pill, you could get pregnant.
    Pills containing gestodene or desogestrelare not advised for women with increased risk of blood clots such as those with varicose veins or angina. Tell your doctor if you have hypertension, diabetes, multiple sclerosis or you smoke.
    Progesterone-only pills can occasionally cause acne and ovarian cancer.
 

    A three month course of oral antibiotics is needed. However, irritation of the gut lining, diarrhœa and stomach ulcers are a risk factor.
    They may also cause skin irritation or allergies. Dr Jamil says: "Tummy upsets will come on within 24 hours and you may feel the other side-effects in a few days.
    Some are easier on the stomach than others but as it varies from person to person – you may just have to try different types. Luckily there are lots of antibiotics for acne.
Vitamin A. Roaccutane, a strong vitimin A based treatment is very effective for severe acne which is unresponsive to antibiotics.

    You may experience skin dryness, nausea, headaches, drowsiness, sweating, menstrual irregularities and seizures, depression and mood swings.
 

• The above is an abbreviated guide listing the most common side effects. Always consult you doctor or pharmacist before taking medication.
  For further details (in UK) speak to your pharmacist or visit www.drugdigest.org.
  www.healthsquare.com.
  www.rxlist.com,
  or contact the Mental Health Foundation on 020 7535 7400 or visit www.mentalhealth.org.uk